Background: This study aimed to assess the pathogenicity of newly identified tuberous sclerosis Complex 1 (TSC1) and TSC2 variants, contributing definitive evidence for the diagnosis of TSC. Methods: A total of 103 TSC patients underwent TSC genetic testing using standardized protocols, and genetic testing was extended to their respective families. Analysis of genetic testing results considered clinical phenotype and gene pathogenicity based on the 2012 revision of the International Society of TSC. Results: Among participants, 12 exhibited previously unreported variants of TSC1 or TSC2 gene absent in relevant databases. All 12 clinically diagnosed TSC patients presented typical phenotypes, such as brain lesions and skin changes. Notably, there were 2 variants of TSC1 gene and 10 variants of TSC2 gene, encompassing 8 frameshift variants, 2 nonsense variants, and 2 missense variants. Conclusions: This study broadens the spectrum of variants of TSC1 and TSC2 genes, reaffirming the clinical diagnosis of patients through genetic testing.

Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder caused by pathogenic variants of TSC1 or TSC2 genes, leading to dysregulation of the mammalian target of rapamycin (mTOR) pathway. This dysregulation results in the formation of organ-specific tumors and neurological manifestations such as seizures, intellectual disability, and developmental delays. These characteristic clinical features are crucial for diagnosis, and genetic testing is playing an increasingly significant role. Long-term disease monitoring and appropriate interventions by multidisciplinary experts, including the use of mTOR inhibitors and promising therapeutic agents based on disease pathomechanisms, are essential for effective TSC management and improved clinical outcomes.

The tuberous sclerosis complex (TSC1/TSC2/TBC1D7) primarily functions to inhibit the mechanistic target of rapamycin complex 1 (mTORC1), a crucial regulator of cell growth. Mutations in TSC1 or TSC2 cause tuberous sclerosis complex (TSC), a rare autosomal dominant genetic disorder marked by benign tumors in multiple organs that rarely progress to malignancy. Traditionally, TSC proteins are considered tumor suppressive due to their inhibition of mTORC1 and other mechanisms. However, more recent studies have shown that TSC proteins can also promote tumorigenesis in certain cancer types. In this review, we explore the composition and function of the TSC protein complex, the roles of its individual components in cancer biology, and potential future therapeutic targeting strategies.

In restricted regions of the rodent brain, neurogenesis persists throughout life, hinting that perhaps similar phenomena may exist in humans. Neural stem cells (NSCs) that reside within the ventricular-subventricular zone (V-SVZ) continually produce functional cells, including neurons that integrate into the olfactory bulb circuitry. The ability to achieve this feat is based on genetically encoded transcriptional programs that are controlled by environmentally regulated post-transcriptional signaling pathways. One such pathway that molds V-SVZ neurogenesis is the mTOR pathway. This pathway integrates nutrient sufficiency with growth factor signaling to control distinct steps of neurogenesis. Alterations in mTOR pathway signaling occur in numerous neurodevelopmental disorders. Here, we provide a narrative review for the role of the mTOR pathway in this process and discuss the use of this region to study the mTOR pathway in both health and disease.

Tuberous Sclerosis Complex (TSC) is a debilitating developmental disorder characterized by a variety of clinical manifestations. While benign tumors in the heart, lungs, kidney, and brain are all hallmarks of the disease, the most severe symptoms of TSC are often neurological, including seizures, autism, psychiatric disorders, and intellectual disabilities. TSC is caused by loss of function mutations in the TSC1 or TSC2 genes and consequent dysregulation of signaling via mechanistic Target of Rapamycin Complex 1 (mTORC1). While TSC neurological phenotypes are well-documented, it is not yet known how early in neural development TSC1/2-mutant cells diverge from the typical developmental trajectory. Another outstanding question is the contribution of homozygous-mutant cells to disease phenotypes and whether phenotypes are also present in the heterozygous-mutant populations that comprise the vast majority of cells in patients. Using TSC patient-derived isogenic induced pluripotent stem cells (iPSCs) with defined genetic changes, we observed aberrant early neurodevelopment in vitro, including misexpression of key proteins associated with lineage commitment and premature electrical activity. These alterations in differentiation were coincident with hundreds of differentially methylated DNA regions, including loci associated with key genes in neurodevelopment. Collectively, these data suggest that mutation or loss of TSC2 affects gene regulation and expression at earlier timepoints than previously appreciated, with implications for whether and how prenatal treatment should be pursued.

Subependymal giant cell astrocytomas (SEGAs) are one of the predominant features of the tuberous sclerosis complex (TSC). Before the use of mTOR inhibitors (mTORi; everolimus and sirolimus) in TSC, many patients had to undergo surgical operations (both preemptively and emergently). However, with mTORis gaining increased use, the role of medical and surgical therapy in SEGA is unclear.

The authors have based this review on publications listed in PubMed that delve into the role of surgery and mTORi in the treatment of SEGAs.

There is no sizable head-to-head comparison of surgery and medical therapy in treating SEGA. Factors that reduce the ability to do these types of studies are the lack of uniform diagnosis of SEGA, provider preference for treatment, and variability in each treatment group (dosing of mTORis and various surgical providers). However, with the safety of mTORi, the authors recommend starting mTORi therapy for any growth in a nodule on serial scans and relying on surgery only for failed mTORi therapy.

Tuberous sclerosis complex (TSC) is an autosomal dominant inherited disease characterized by systemic hamartomas, neuropsychiatric symptoms known as TAND (TSC-associated neuropsychiatric disorders), and vitiligo. These symptoms are attributed to the constant activation of mechanistic target of rapamycin complex 1 (mTORC1) caused by genetic mutations in the causative genes TSC1 or TSC2. The elucidation of the pathogenesis of this disease and advances in diagnostic technologies have led to dramatic changes in the diagnosis and treatment of TSC. Diagnostic criteria have been created at a global level, and mTORC1 inhibitors have emerged as therapeutic agents for this disease. Previously, the treatment strategy was limited to symptomatic treatments such as surgery. Inhibitors of mTORC1 are effective against all symptoms of TSC, but they also have systemic side effects. Therefore, the need for a cross-disciplinary, collaborative medical care system has increased, resulting in the establishment of a practice structure known as the "TSC Board." Furthermore, to reduce the side effects of systemic administration of mTORC1 inhibitors, a topical formulation of mTORC1 inhibitor was developed in Japan for the treatment of skin lesions caused by TSC. This report summarizes the pathogenesis and current status of TSC and the contribution of the Neurocutaneous Syndrome Policy Research Group to the policies of the Ministry of Health, Labor, and Welfare with respect to this rare, intractable disease.

Perivascular epithelioid cell neoplasms (PEComas) and epithelioid angiomyolipomas (EAMLs) are two different denominations for the same "mesenchymal tumor composed of histologically and immunohistochemically distinctive perivascular epithelioid cells". Hepatic PEComa/EAML is a very rare neoplasm, and only 29 case reports of hepatic PEComa and 25 of hepatic EAML have been reported in the current literature. A clear female predominance with a mean age at diagnosis of 42.5 years old can be observed by literature review. Ultrasound (US) examination was the first-line diagnostic technique in most of the cases of hepatic PEComa, but it was documented in very few cases of hepatic EAML. A great variability in the ultrasonographic B-mode, color Doppler and contrast-enhanced ultrasonography (CEUS) features of hepatic PEComa/EAML emerges. Computed tomography and magnetic resonance were the most common used techniques to confirm the nature of the hepatic lesion, even if the anatomo-pathological examination was the only technique to display a certainty diagnosis and to differentiate hepatic PEComa/EAML from benign and malignant hepatic lesions. The great majority of hepatic PEComas/EAMLs are surgically treated without any adjuvant therapy.

Tuberous sclerosis complex (TSC) is a multisystemic genetic disorder with clinical variability. As the needs of children with TSC may differ, parenting demands may similarly differ. Characterizing parenting stress, or emotional maladaptation from parenting duties, can enable health care providers to assist parents of children with TSC.

Multiple methods were used to survey 269 parents of children (aged zero to 12 years) with TSC. The Parenting Stress Index (PSI) measured parenting stress, and children's TSC clinical, seizure, and neuropsychiatric features were obtained. A qualitative free response item asked parents to describe significant parenting stressors for a child with TSC.

Half of the participants achieved a clinically relevant PSI composite score with a high representation of the PSI subdomain, Parent-Child Dysfunction. Parents reported higher stress for children with certain skin and ocular TSC features, intractable epilepsy with or without status epilepticus, developmental delay or intellectual disability, TSC-associated neuropsychiatric disorders, and parent race and income. These variables accounted for 46% of PSI variability. Thematic analyses identified stressors consistent with survey findings and other novel constructs like uncertainty and a lack of personal or health care support.

These results could be used to improve parenting stress by counseling on the dermatologic and ophthalmologic TSC findings, anticipatory guidance on seizure symptoms, maximizing early childhood intervention or related therapies, and providing psychosocial assessment to all parents with a low threshold for referral to a mental health specialist. These considerations may ameliorate parenting stress and ultimately improve quality of life for families and patients with TSC.

Nutrient-dependent mTORC1 regulation upon amino acid deprivation is mediated by the KICSTOR complex, comprising SZT2, KPTN, ITFG2, and KICS2, recruiting GATOR1 to lysosomes. Previously, pathogenic SZT2 and KPTN variants have been associated with autosomal recessive intellectual disability and epileptic encephalopathy. We identified bi-allelic KICS2 variants in eleven affected individuals presenting with intellectual disability and epilepsy. These variants partly affected KICS2 stability, compromised KICSTOR complex formation, and demonstrated a deleterious impact on nutrient-dependent mTORC1 regulation of 4EBP1 and S6K. Phosphoproteome analyses extended these findings to show that KICS2 variants changed the mTORC1 proteome, affecting proteins that function in translation, splicing, and ciliogenesis. Depletion of Kics2 in zebrafish resulted in ciliary dysfunction consistent with a role of mTORC1 in cilia biology. These in vitro and in vivo functional studies confirmed the pathogenicity of identified KICS2 variants. Our genetic and experimental data provide evidence that variants in KICS2 are a factor involved in intellectual disability due to its dysfunction impacting mTORC1 regulation and cilia biology.

Tuberous sclerosis complex is a genetic disorder caused by mutations in the TSC1 or TSC2 genes, affecting multiple systems. These genes produce proteins that regulate mTORC1 activity, essential for cell function and metabolism. While mTOR inhibitors have advanced treatment, maintaining long-term therapeutic success is still challenging. For over 20 years, significant progress has linked TSC1 or TSC2 gene mutations in stem cells to tuberous sclerosis complex symptoms.

A comprehensive review was conducted using databases like Web of Science, Google Scholar, PubMed, and Science Direct, with search terms such as "tuberous sclerosis complex," "TSC1," "TSC2," "stem cell," "proliferation," and "differentiation." Relevant literature was thoroughly analyzed and summarized to present an updated analysis of the TSC1-TSC2 complex's role in stem cell fate determination and its implications for tuberous sclerosis complex.

The TSC1-TSC2 complex plays a crucial role in various stem cells, such as neural, germline, nephron progenitor, intestinal, hematopoietic, and mesenchymal stem/stromal cells, primarily through the mTOR signaling pathway.

This review aims shed light on the role of the TSC1-TSC2 complex in stem cell fate, its impact on health and disease, and potential new treatments for tuberous sclerosis complex.

Although cancer is rare in children and adolescents, it remains a leading cause of death within this age range, and genetic predisposition is the main known risk factor. Since the discovery of retinoblastoma-predisposing RB1 pathogenic germline variants in 1985, several additional high-penetrance cancer predisposition genes (CPGs) have been identified. Although few clinically recognizable genetic conditions display moderate cancer phenotypes, burden testing has revealed low-to-moderate penetrance CPGs. In addition to germline pathogenic variants in CPGs, postzygotic somatic mosaic CPG pathogenic variants acquired during embryonic development are increasingly recognized as factors that predispose children and adolescents to malignancies. Genome-wide association studies of various childhood and adolescent cancer types have identified some common low-risk cancer susceptibility alleles. Although the clinical utility of polygenic risk scores is currently limited in children and adolescents, polygenic risk scores developed for adults can predict subsequent cancer risks in childhood and adolescent cancer survivors. In this Review, I describe our current knowledge of genetic predisposition to childhood and adolescent cancers. Survival rates in children and adolescents with cancer and CPGs are often poor, necessitating better integration of genomic testing into clinical care to improve cancer prevention, surveillance and therapies.

The TSC complex formed by TSC1 and TSC2 is the most important upstream negative regulator of mTORC1. Genetic variations in either TSC1 or TSC2 cause tuberous sclerosis complex (TSC) disease which is a rare autosomal dominant disorder resulting in impairment of multiple organ systems. In this study, besides a reported variation, c.2509_2512del (p.Asn837Valfs*11, p.N837fs) in TSC1, we found a de novo TSC2 variation c.1113delG (p.Gln371Hisfs*18, p.Q371fs), which these two mutation influence the formation of TSC complex. We found that the decrease of TSC complex with the appearance of the decreased miR-199b-3p expression. At the same time, the reduction of miR-199b-3p increased the expression of mTOR and the activation of mTORC1 and mTORC2, the additional miR-199b-3p caused the decrease the expression of mTOR and the activation of mTORC1 and mTORC2. In brief, our results may illustrate a novel mechanism of TSC caused by variations in either TSC1 or TSC2, and a new mTOR expression regulator, miR-199b-3p.

Epilepsy and intellectual disability are common in tuberous sclerosis complex (TSC). Although early life seizures and intellectual disability are known to be correlated in TSC, the differential effects of age at seizure onset and accumulated seizure burden on development remain unclear.

Daily seizure diaries, serial neurodevelopmental testing, and brain magnetic resonance imaging were analyzed for 129 TSC patients followed from 0 to 36 months. We used machine learning to identify subgroups of patients based on neurodevelopmental test scores at 36 months of age and assessed the stability of those subgroups at 12 months. We tested the ability of candidate biomarkers to predict 36-month neurodevelopmental subgroup using univariable and multivariable logistic regression. Candidate biomarkers included age at seizure onset, accumulated seizure burden, tuber volume, sex, and earlier neurodevelopmental test scores.

Patients clustered into two neurodevelopmental subgroups at 36 months of age, higher and lower scoring. Subgroup was mostly (75%) the same at 12 months. Significant univariable effects on subgroup were seen only for accumulated seizure burden (largest effect), earlier test scores, and tuber volume. Neither age at seizure onset nor sex significantly distinguished 36-month subgroups, although for girls but not boys there was a significant effect of age at seizure onset. In the multivariable model, accumulated seizure burden and earlier test scores together predicted 36-month neurodevelopmental group with 82% accuracy and an area under the curve of .86.

These results untangle the contributions of age at seizure onset and accumulated seizure burden to neurodevelopmental outcomes in young children with TSC. Accumulated seizure burden, rather than the age at seizure onset, most accurately predicts neurodevelopmental outcome at 36 months of age. These results emphasize the need to manage seizures aggressively during the first 3 years of life for patients with TSC, not only to promote seizure control but to optimize cognitive function.

Pathogenic mutations in the genes associated with tuberous sclerosis complex (TSC)/mTOR pathway are linked to histologically diverse renal cell neoplasms, including eosinophilic solid and cystic renal cell carcinoma (ESC RCC), low grade oncocytic tumor (LOT), eosinophilic vacuolated tumor (EVT), and xanthomatous giant cell renal cell carcinoma (XGC RCC). Here, we validate a TSC2 immunohistochemistry (IHC) assay by comparison to genomic data in these neoplasms. Automated TSC2 IHC was performed on formalin-fixed paraffin embedded (FFPE) tissues from 38 genetically-confirmed TSC/mTOR-associated renal tumors (6 ESCs, 16 EVTs, 13 LOTs, 2 XGC and 1 clear cell RCC) and visually scored in a semi-dichotomous fashion compared to internal control tissue. The positive predictive value (PPV) of TSC2 protein loss for underlying pathogenic mutation in TSC2 was 92% (11/12), while the negative predictive value (NPV) of intact TSC2 by IHC for lack of underlying pathogenic mutation in TSC2 was 81% (21/26). Intact TSC2 by IHC was 95% (21/22) specific for absence of underlying pathogenic TSC2 mutation. All the cases lacking TSC2 mutation with intact TSC2 protein had an underlying mutation in TSC1, MTOR or PIK3CA. Loss of TSC2 was 77% (10/13) sensitive for underlying TSC2 truncation mutations and 33% (1/3) sensitive for underlying TSC2 missense mutations. Overall, 73% (8/11) tumors with TSC2 IHC loss and underlying pathogenic alterations in TSC2 showed heterogeneous protein loss, with rare interspersed positively staining tumor cells. These data support TSC2 IHC as a potentially useful assay for the diagnostic workup of renal tumors suspected to belong to the TSC/mTOR-associated subgroups.

The genetic landscape of corticotroph tumours of the pituitary gland has dramatically changed over the last 10 years. Somatic changes in the USP8 gene account for the most common genetic defect in corticotrophinomas, especially in females, while variants in TP53 or ATRX are associated with a subset of aggressive tumours. Germline defects have also been identified in patients with Cushing's disease: some are well-established (MEN1, CDKN1B, DICER1), while others are rare and could represent coincidences. In this review, we summarise the current knowledge on the genetic drivers of corticotroph tumorigenesis, their molecular consequences, and their impact on the clinical presentation and prognosis.

Tuberous sclerosis complex (TSC) is an autosomal dominant neurodevelopmental disorder and multisystem disease caused by pathogenic DNA alterations in the TSC1 and TSC2 tumor suppressor genes. A molecular genetic diagnosis of TSC confirms the clinical diagnosis, facilitating the implementation of appropriate care and surveillance. TSC1 and TSC2 encode the core components of the TSC1/2 complex (TSC1/2), a negative regulator of the mechanistic target of rapamycin (MTOR) complex 1 (TORC1). Functional analysis of the effects of TSC1 and TSC2 variants on TORC1 activity can help establish variant pathogenicity. We searched for pathogenic alterations to TSC1 and TSC2 in DNA isolated from 116 individuals with a definite clinical diagnosis of TSC. Missense variants and in-frame deletions were functionally assessed. Pathogenic DNA alterations were identified in 106 cases (91%); 18 (17%) in TSC1 and 88 (83%) in TSC2. Of these, 35 were novel. Disruption of TSC1/2 activity was demonstrated for seven TSC2 variants. Molecular diagnostics confirms the clinical diagnosis of TSC in a large proportion of cases. Functional assessment can help establish variant pathogenicity and is a useful adjunct to DNA analysis.

The mammalian target of Rapamycin complex 1 (mTORC1) is a serine/threonine kinase that couples nutrient and growth factor signaling to the cellular control of metabolism and plays a fundamental role in aberrant proliferation in cancer. mTORC1 has previously been considered an "on/off" switch, capable of phosphorylating the entire pool of its substrates when activated. However, recent studies have indicated that mTORC1 may be active toward its canonical substrates, eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1) and S6 kinase (S6K), involved in mRNA translation and protein synthesis, and inactive toward TFEB and TFE3, transcription factors involved in the regulation of lysosome biogenesis, in several pathological contexts. Among these conditions are Birt-Hogg-Dubé syndrome (BHD) and, recently, tuberous sclerosis complex (TSC). Furthermore, increased TFEB and TFE3 nuclear localization in these syndromes, and in translocation renal cell carcinomas (tRCC), drives mTORC1 activity toward the canonical substrates, through the transcriptional activation of the Rag GTPases, thereby positioning TFEB and TFE3 upstream of mTORC1 activity toward 4EBP1 and S6K. The expanding importance of TFEB and TFE3 in the pathogenesis of these renal diseases warrants a novel clinical grouping that we term "TFEopathies." Currently, there are no therapeutic options directly targeting TFEB and TFE3, which represents a challenging and critically required avenue for cancer research.

Mesenchymal neoplasms composed of vascular, smooth muscle, and adipocytic components are uncommon in the nasal cavity. While angioleiomyoma (AL) is a smooth muscle tumor in the Head & Neck WHO classification, it is considered of pericytic origin in the Skin as well as Soft Tissue and Bone classifications. For nasal AL with an adipocytic component, the terms AL with adipocytic differentiation and angiomyolipoma (AML) have been applied, among others. AML is a type of perivascular epithelioid cell tumor (PEComa), most often arising in the kidney, sometimes associated with the tuberous sclerosis complex (TSC). It is uncertain whether nasal cavity AML and AL are best considered hamartomas or neoplasms, as their genetics are largely unexplored.

We performed a multi-institutional retrospective study of nasal cavity mesenchymal lesions. Patient demographics, clinical histories, and histologic and immunohistochemical findings were collected. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tissue and analyzed by SNP-based chromosomal microarray, targeted RNA fusion sequencing, and whole-exome sequencing.

Fifteen lesions (3-42 mm) were identified, predominantly in male (87%) patients with a median age of 60. Patients typically presented with obstructive symptoms, and none had a history of TSC. One AL was a recurrence from six years prior; 11 cases showed no recurrence (median 4.7 years, range: 0.88-12.4). Morphologically, 11 AML contained 30-80% smooth muscle, 10-25% vasculature, and 2-60% adipose tissue, while four AL contained 70-80% smooth muscle and 20-30% vasculature. Other histologic observations included ulceration, thrombosis, inflammation, myxoid change, senescent nuclei, and extramedullary hematopoiesis; no well-developed epithelioid cell morphology was identified. Immunohistochemically, all cases were positive for smooth muscle markers (actin, desmin, and/or caldesmon) and negative for melanocytic markers. Molecular analysis revealed loss of 3p and 11q in a single AML. No other known pathogenic copy number or molecular alterations were seen, including in TSC1/2, TFE3, or NOTCH2.

Nasal cavity AML lacks morphologic, immunophenotypic, and genetic features of PEComa family AML. The significant histologic overlap between nasal AML and AL without distinguishing molecular features in either entity suggests "sinonasal angioleiomyoma with adipocytic differentiation" may be the most appropriate terminology for hybrid vascular and smooth muscle lesions containing adipocytic components.

Tuberous sclerosis complex (TSC) is a variable multisystem disorder. The "no mutations identified" (NMI) group are reportedly phenotypically milder than those with an identified molecular cause, and often have mosaic or intronic variants not detected by standard sequencing methods.

We describe the phenotypes in an Australian TSC NMI group (n = 18) and a molecular testing strategy implementable in a diagnostic laboratory. Massively parallel sequencing (MPS) of the whole genomic regions of TSC1 and TSC2 was performed using DNA extracted from multiple tissue samples per participant.

Our study showed that the phenotype in TSC NMI individuals can be similar to those with heterozygous, particularly TSC1, variants. Although neurodevelopmental outcomes can be less severe, the number of organ systems involved was similar to the non-mosaic groups. A diagnostic yield of 72% (13/18) was achieved, with the majority (10/13) being mosaic variants and the remainder heterozygous variants missed on previous testing.

Testing DNA from multiple tissue samples allowed for validation of otherwise discarded low-level mosaic variants and detection of mosaic variants by MPS without excessive cost or the need for specialised techniques. Implementing this approach in a diagnostic setting is viable and allows optimal clinical care of patients with NMI TSC.

Mesenchymal neoplasms composed of vascular, smooth muscle, and adipocytic components are uncommon in the nasal cavity. While angioleiomyoma (AL) is a smooth muscle tumor in the Head & Neck WHO classification, it is considered of pericytic origin in the Skin as well as Soft Tissue and Bone classifications. For nasal AL with an adipocytic component, the terms AL with adipocytic differentiation and angiomyolipoma (AML) have been applied, among others. AML is a type of perivascular epithelioid cell tumor (PEComa), most often arising in the kidney, sometimes associated with the tuberous sclerosis complex (TSC). It is uncertain whether nasal cavity AML and AL are best considered hamartomas or neoplasms, as their genetics are largely unexplored.

We performed a multi-institutional retrospective study of nasal cavity mesenchymal lesions. Patient demographics, clinical histories, and histologic and immunohistochemical findings were collected. DNA and RNA were extracted from formalin-fixed, paraffin-embedded tissue and analyzed by SNP-based chromosomal microarray, targeted RNA fusion sequencing, and whole-exome sequencing.

Fifteen lesions (3 to 42 mm) were identified predominantly in male (87%) patients with a median age of 60. Patients typically presented with obstructive symptoms, and none had a history of TSC. One AL was a recurrence from six years prior; 11 cases showed no recurrence (median 4.7 years, range: 0.88-12.4). Morphologically, 11 AMLs contained 30-80% smooth muscle, 10-25% vasculature, and 2-60% adipose tissue, while four ALs contained 70-80% smooth muscle and 20-30% vasculature. Other histologic observations included surface ulceration, vascular thrombosis, chronic inflammation, and myxoid change; no well-developed epithelioid cell morphology was identified. Immunohistochemically, all cases were positive for smooth muscle markers (actin and/or desmin) and negative for melanocytic markers. Molecular analysis revealed loss of 3p and 11q in a single AML. No other known pathogenic copy number or molecular alterations were seen, including in TSC1/2, TFE3, or NOTCH2.

Nasal cavity AML lacks morphologic, immunophenotypic, and genetic features of PEComa family AMLs. The significant histologic overlap between nasal AML and AL without distinguishing molecular features in either entity suggests "sinonasal angioleiomyoma with adipocytic differentiation" may be the most appropriate terminology for hybrid vascular and smooth muscle lesions containing adipocytic components.

Tuberous sclerosis (TSC) is an autosomal dominant neurocutaneous disorder. This case highlights rare isolated neurologic finding in a TSC patient emphasizing the need for heightened suspicion even in the absence of any cutaneous findings and family history.

Recent genetic and genomic advancements have elucidated the complex etiology of idiopathic pulmonary fibrosis (IPF) and other progressive fibrotic interstitial lung diseases (ILDs), emphasizing the contribution of heritable factors. This state-of-the-art review synthesizes evidence on significant genetic contributors to pulmonary fibrosis (PF), including rare genetic variants and common SNPs. The MUC5B promoter variant is unusual, a common SNP that markedly elevates the risk of early and established PF. We address the utility of genetic variation in enhancing understanding of disease pathogenesis and clinical phenotypes, improving disease definitions, and informing prognosis and treatment response. Critical research gaps are highlighted, particularly the underrepresentation of non-European ancestries in PF genetic studies and the exploration of PF phenotypes beyond usual interstitial pneumonia/IPF. We discuss the role of telomere length, often critically short in PF, and its link to progression and mortality, underscoring the genetic complexity involving telomere biology genes (TERT, TERC) and others like SFTPC and MUC5B. In addition, we address the potential of gene-by-environment interactions to modulate disease manifestation, advocating for precision medicine in PF. Insights from gene expression profiling studies and multiomic analyses highlight the promise for understanding disease pathogenesis and offer new approaches to clinical care, therapeutic drug development, and biomarker discovery. Finally, we discuss the ethical, legal, and social implications of genomic research and therapies in PF, stressing the need for sound practices and informed clinical genetic discussions. Looking forward, we advocate for comprehensive genetic testing panels and polygenic risk scores to improve the management of PF and related ILDs across diverse populations.

Tuberous Sclerosis Complex (TSC) is a debilitating developmental disorder characterized by a variety of clinical manifestations. While benign tumors in the heart, lungs, kidney, and brain are all hallmarks of the disease, the most severe symptoms of TSC are often neurological, including seizures, autism, psychiatric disorders, and intellectual disabilities. TSC is caused by loss of function mutations in the TSC1 or TSC2 genes and consequent dysregulation of signaling via mechanistic Target of Rapamycin Complex 1 (mTORC1). While TSC neurological phenotypes are well-documented, it is not yet known how early in neural development TSC1/2-mutant cells diverge from the typical developmental trajectory. Another outstanding question is the contribution of homozygous-mutant cells to disease phenotypes and whether such phenotypes are also seen in the heterozygous-mutant populations that comprise the vast majority of cells in patients. Using TSC patient-derived isogenic induced pluripotent stem cells (iPSCs) with defined genetic changes, we observed aberrant early neurodevelopment in vitro, including misexpression of key proteins associated with lineage commitment and premature electrical activity. These alterations in differentiation were coincident with hundreds of differentially methylated DNA regions, including loci associated with key genes in neurodevelopment. Collectively, these data suggest that mutation or loss of TSC2 affects gene regulation and expression at earlier timepoints than previously appreciated, with implications for whether and how prenatal treatment should be pursued.

Tuberous sclerosis is a rare genetic disorder involving mainly the nervous and cardiovascular systems. The early recognition of the cardiovascular manifestations by the pediatrician allows an appropriate management and therefore enhances the quality of life of the affected children. Cardiac rhabdomyomas and the associated arrhythmias are the first cardiac features and they might represent a diagnosis challenge given their wide spectrum of clinical manifestations. We aimed to provide the paediatric practitioners with current knowledge regarding the cardiovascular complications in children with tuberous sclerosis. We overviewed the antenatal and postnatal evolution of cardiovascular manifestations, the systematic screening and long-term follow-up strategy of cardiac rhabdomyomas and arrhythmias in children with tuberous sclerosis.

A 33-year-old lady was referred to our clinic with a history of left upper eyelid swelling and difficulty to open her left eye for more than 4 years. Her globe was in infero-nasal displacement, and ocular movement was not full, with restriction to every direction. No clinical sign including eye redness, pain or visual loss was found on examination. Exophthalmometry confirmed 2 mm of left-sided proptosis. Computed tomography (CT) imaging of the orbit obtained in axial and coronal planes depicted an irregular and heterogeneous soft-tissue density mass in the left lacrimal gland, measuring 25 × 17 mm. Magnetic resonance imaging (MRI) revealed the mass of slightly longer T1 and slightly longer/shorter T2 signal, and Gd-enhanced MRI showed a significant enhancement. The tumor was first presumably diagnosed of pleomorphic adenomas. A surgery was applied to remove the tumor completely. Histopathological evaluation led to the diagnosis of PEComa.

Autism spectrum disorder (ASD) is a common and highly heritable neurodevelopmental disorder. During the last 15 years, advances in genomic technologies and the availability of increasingly large patient cohorts have greatly expanded our knowledge of the genetic architecture of ASD and its neurobiological mechanisms. Over two hundred risk regions and genes carrying rare de novo and transmitted high-impact variants have been identified. Additionally, common variants with small individual effect size are also important, and a number of loci are now being uncovered. At the same time, these new insights have highlighted ongoing challenges. In this perspective article, we summarize developments in ASD genetic research and address the enormous impact of large-scale genomic initiatives on ASD gene discovery.

Genomic mosaicism arising from mosaic variants is a phenomenon that describes the presence of a cell or cell populations with different genome compositions from the germline cells of an individual. It comprises all types of genetic variants. A large proportion of childhood genetic disorders are defined as being de novo, meaning that the disease-causing mutations are only detected in the proband, not in any of the parents. Population studies show that 80% of the de novo mutations arise from the paternal haplotype, that is, from paternal sperm mosaicism. This review provides a summary of the types and detection strategies of sperm mosaicism. In addition, it provides discussions on how recent studies demonstrated that genomic mosaic mutations in parents, especially those in the paternal sperms, could be inherited by the offspring and cause childhood disorders. According to the previous findings of the author's research team, sperm mosaicism derived from early embryogenesis and primordial germ cell stages can explain 5% to 20% of the de novo mutations related to clinical phenotypes and can serve as an important predictor of both rare and complex disorders. Sperm mosaicism shows great potential for clinical genetic diagnosis and consultations. Based on the published literature, the author suggests that, large-scale screening for de novo sperm mosaic mutations and population-based genetic screening should be conducted in future studies, which will greatly enhance the risk assessment in the offspring and effectively improve the genetic health at the population level. Implementation of direct sperm detection for de novo mutations will significantly increase the efficiency of the stratification of patient cohorts and improve recurrence risk assessment for future births. Future research in the field should be focused on the impact of environmental and lifestyle factors on the health of the offspring through sperms and their modeling of mutation signatures. In addition, targeted in vitro modeling of sperm mutations will also be a promising direction.

It is usually considered that only 5% of all pituitary neuroendocrine tumours are due to inheritable causes. Since this estimate was reported, however, multiple genetic defects driving syndromic and nonsyndromic somatotrophinomas have been unveiled. This heterogeneous genetic background results in overlapping phenotypes of GH excess. Genetic tests should be part of the approach to patients with acromegaly and gigantism because they can refine the clinical diagnoses, opening the possibility to tailor the clinical conduct to each patient. Even more, genetic testing and clinical screening of at-risk individuals have a positive impact on disease outcomes, by allowing for the timely detection and treatment of somatotrophinomas at early stages. Future research should focus on determining the actual frequency of novel genetic drivers of somatotrophinomas in the general population, developing up-to-date disease-specific multi-gene panels for clinical use, and finding strategies to improve access to modern genetic testing worldwide.

Tuberous Sclerosis Complex 1 and 2 proteins, TSC1 and TSC2 respectively, participate in a multiprotein complex with a crucial role for the proper development and function of the nervous system. This complex primarily acts as an inhibitor of the mechanistic target of rapamycin (mTOR) kinase, and mutations in either TSC1 or TSC2 cause a neurodevelopmental disorder called Tuberous Sclerosis Complex (TSC). Neurological manifestations of TSC include brain lesions, epilepsy, autism, and intellectual disability. On the cellular level, the TSC/mTOR signaling axis regulates multiple anabolic and catabolic processes, but it is not clear how these processes contribute to specific neurologic phenotypes. Hence, several studies have aimed to elucidate the role of this signaling pathway in neurons. Of particular interest are axons, as axonal defects are associated with severe neurocognitive impairments. Here, we review findings regarding the role of the TSC1/2 protein complex in axons. Specifically, we will discuss how TSC1/2 canonical and non-canonical functions contribute to the formation and integrity of axonal structure and function.

Neurocutaneous disorders, also known as phakomatoses, are congenital and acquired syndromes resulting in simultaneous neurologic and cutaneous involvement. In several of these conditions, the genetic phenomenon is understood, providing a pivotal role in the development of therapeutic options. This review encompasses the discussion of the genetic and clinical involvement of neurocutaneous disorders, and examines clinical management and treatment options. With the current advances in genetics, the role of precision medicine and targeted therapy play a substantial role in addressing the management of these conditions. The interconnectedness between therapeutic options highlights the importance of precision medicine in treating each disorder's unique molecular pathway. This review provides an extensive synthesis of ongoing and current therapeutics in the management of such clinically unique and challenging conditions.

The mechanistic target of rapamycin (mTOR) pathway serves as a master regulator of cell growth, proliferation, and survival. Upregulation of the mTOR pathway has been shown to cause malformations of cortical development, medically refractory epilepsies, and neurodevelopmental disorders, collectively described as mTORopathies. Tuberous sclerosis complex (TSC) serves as the prototypical mTORopathy. Characterized by the development of benign tumors in multiple organs, pathogenic variants in TSC1 or TSC2 disrupt the TSC protein complex, a negative regulator of the mTOR pathway. Variants in critical domains of the TSC complex, especially in the catalytic TSC2 subunit, correlate with increased disease severity. Variants in less crucial exons and non-coding regions, as well as those undetectable with conventional testing, may lead to milder phenotypes. Despite the assumption of complete penetrance, expressivity varies within families, and certain variants delay disease onset with milder neurological effects. Understanding these genotype-phenotype correlations is crucial for effective clinical management. Notably, 15% of patients have no mutation identified by conventional genetic testing, with the majority of cases postulated to be caused by somatic TSC1/TSC2 variants which present complex diagnostic challenges. Advancements in genetic testing, prenatal screening, and precision medicine hold promise for changing the diagnostic and treatment paradigm for TSC and related mTORopathies. Herein, we explore the genetic and molecular mechanisms of TSC and other mTORopathies, emphasizing contemporary genetic methods in understanding and diagnosing the condition.

Vascular involvement in tuberous sclerosis complex (TSC) is uncommon and even more so in pediatric patients. When asymptomatic, these vascular abnormalities carry increased risk of rupture with increased morbidity and mortality. Here, we describe a case of a ruptured unrecognized abdominal aortic aneurysm in an 11-month-old patient with a history of TSC. The abdominal aortic aneurysm was discovered at autopsy and highlights the rarity of abdominal aortic aneurysm in pediatric patients diagnosed with TSC and the importance of screening for associated aneurysmal disease in the pediatric population with TSC. Furthermore, the extensive retroperitoneal hemorrhage seen in this case also highlights a rare but potential mimic of abuse in the pediatric population.

Tuberous sclerosis complex (TSC) is a rare autosomal dominant genetic disorder that affects multiple organ systems. Mutations in the TSC1 and TSC2 genes result in the constitutive hyperactivation of the mammalian target of rapamycin (mTOR) pathway, contributing to the growth of benign tumors or hamartomas in various organs. Due to the implication of mTOR pathway dysregulation in the disease pathology, increasing evidence supports the use of mTOR inhibitors for treating multiple manifestations of TSC.

In this study, we conducted a retrospective analysis of clinical findings and treatment data from 38 patients diagnosed with tuberous sclerosis who were followed up in the Pediatric Oncology Clinic between 2010 and 2020. We collected information on patients' ages, genders, affected sites, familial history, imaging findings, presence of tumors, and treatments.

Among the patients, nine individuals with TSC manifestations were treated with mTOR inhibitors. Specifically, everolimus was successfully administered to five patients with inborn cardiac rhabdomyoma causing hemodynamic impairment. In addition, two patients with refractory seizures received everolimus in combination with anti-epileptic drugs. A patient with renal angiomyolipomas larger than 3 cm was treated with everolimus, while a patient with extensive facial angiofibroma received topical sirolimus. All patients tolerated the mTOR inhibitors well, and the side effects were deemed acceptable.

The utilization of mTOR inhibition in TSC is expected to become more prevalent in clinical practice, as current research is anticipated to provide a better understanding of the therapeutic roles of these treatments in TSC.

Human pluripotent stem cell (hPSC)-derived kidney organoids share similarities with the fetal kidney. However, the current hPSC-derived kidney organoids have some limitations, including the inability to perform nephrogenesis and lack of a corticomedullary definition, uniform vascular system, and coordinated exit pathway for urinary filtrate. Therefore, further studies are required to produce hPSC-derived kidney organoids that accurately mimic human kidneys to facilitate research on kidney development, regeneration, disease modeling, and drug screening. In this review, we discussed recent advances in the generation of hPSC-derived kidney organoids, how these organoids contribute to the understanding of human kidney development and research in disease modeling. Additionally, the limitations, future research focus, and applications of hPSC-derived kidney organoids were highlighted.

Tuberous Sclerosis Complex (TSC) is caused by loss of function germline variants in the TSC1 or TSC2 tumor suppressor genes. Genetic testing for the detection of pathogenic variants in either TSC1 or TSC2 was implemented as a diagnostic criterion for TSC. However, TSC molecular diagnosis can be challenging due to the absence of variant hotspots and the high number of variants described. This review aimed to perform an overview of TSC1/2 variants submitted in the ClinVar database. Variants of uncertain significance (VUS), missense and single nucleotide variants were the most frequent in clinical significance (37-40%), molecular consequence (37%-39%) and variation type (82%-83%) categories in ClinVar in TSC1 and TSC2 variants, respectively. Frameshift and nonsense VUS have potential for pathogenic reclassification if further functional and segregation studies were performed. Indeed, there were few functional assays deposited in the database and literature. In addition, we did not observe hotspots for variation and many variants presented conflicting submissions regarding clinical significance. This study underscored the importance of disseminating molecular diagnostic results in a public database to render the information largely accessible and promote accurate diagnosis. We encourage the performance of functional studies evaluating the pathogenicity of TSC1/2 variants.

Although most primary central and peripheral nervous system (NS) tumors occur sporadically, there are a subset that may arise in the context of a cancer predisposition syndrome. These syndromes occur due to a pathogenic mutation in a gene that normally functions as a tumor suppressor. With increased understanding of the molecular pathogenesis of these tumors, more people have been identified with a cancer predisposition syndrome. Identification is crucial, as this informs surveillance, diagnosis, and treatment options. Moreover, relatives can also be identified through genetic testing. Although there are many cancer predisposition syndromes that increase the risk of NS tumors, in this review, we focus on three of the most common cancer predisposition syndromes, neurofibromatosis type 1, neurofibromatosis type 2, and tuberous sclerosis complex type 1 and type 2, emphasizing the clinical manifestations, surveillance guidelines, and treatment options.

There is evidence that viral infections during pre-natal development constitute a risk factor for neuropsychiatric disorders and lead to learning and memory deficits. However, little is known about why viral infections during early post-natal development have a different impact on learning and memory depending on the sex of the subject. We previously showed that early post-natal immune activation induces hippocampal-dependent social memory deficits in a male, but not in a female, mouse model of tuberous sclerosis complex (TSC; Tsc2+/- mice). Here, we explored the impact of a viral-like immune challenge in object memory. We demonstrate that early post-natal immune activation (during the first 2 weeks of life) leads to object memory deficits in female, but not male, mice that are heterozygous for a gene responsible for tuberous sclerosis complex (Tsc2+/- mice), while no effect was observed in wild type (WT) mice. Moreover, we found that the same immune activation in Tsc2+/- adult mice was not able to cause object memory deficits in females, which suggests that the early post-natal development stage constitutes a critical window for the effects of immune challenge on adult memory. Also, our results suggest that mTOR plays a critical role in the observed deficit in object memory in female Tsc2+/- mice. These results, together with previous results published by our laboratory, showing sex-specific memory deficits due to early post-natal immune activation, reinforce the necessity of using both males and females for research studies. This is especially true for studies related to immune activation, since the higher levels of estrogens in females are known to affect inflammation and to provide neuroprotection.

Over the last decade, the comorbidity between Autism Spectrum Disorder (ASD) and epilepsy has been widely demonstrated, and many hypotheses regarding the common neurobiological bases of these disorders have been put forward. A variable, but significant, prevalence of abnormalities on electroencephalogram (EEG) has been documented in non-epileptic children with ASD; therefore, several scientific studies have recently tried to demonstrate the role of these abnormalities as a possible biomarker of altered neural connectivity in ASD individuals. This narrative review intends to summarize the main findings of the recent scientific literature regarding abnormalities detected with standard EEG in children/adolescents with idiopathic ASD. Research using three different databases (PubMed, Scopus and Google Scholar) was conducted, resulting in the selection of 10 original articles. Despite an important lack of studies on preschoolers and a deep heterogeneity in results, some authors speculated on a possible association between EEG abnormalities and ASD characteristics, in particular, the severity of symptoms. Although this correlation needs to be more strongly elucidated, these findings may encourage future studies aimed at demonstrating the role of electrical brain abnormalities as an early biomarker of neural circuit alterations in ASD, highlighting the potential diagnostic, prognostic and therapeutic value of EEG in this field.

Tuberous sclerosis complex (TSC) is a genetic disease leading to malformations, or tubers, in the cerebral cortex and growth of tumors, most frequently in the brain, heart, kidneys, skin, and lungs. Changes in the brain caused by TSC usually have the biggest negative impact on quality of life. Approximately 85% of individuals with TSC have epilepsy, and TSC-associated neuropsychiatric disorders (TAND) affect nearly all individuals with TSC in some way. TSC Alliance's research strategy is built upon both funding and catalyzing research. Through grants, the organization provides funding directly to researchers through a competitive application process. The organization has also built a set of resources available to researchers worldwide, including a Natural History Database, Biosample Repository, and Preclinical Consortium. These resources catalyze research because they are available to qualified academic or industry researchers around the world, enabling an almost unlimited number of scientists to access data and resources to enable and accelerate research on TSC. This research strategy continues to be shaped by the needs and priorities of the TSC community, working toward a future where everyone affected by TSC can live their fullest lives.