Enigma of autism regression mechanistic pathways, clinical phenotypes, and early intervention implications

Table 2 Established vs emerging risk factors of autism regression

Category	Established factors (strong evidence)	Emerging factors (2025 research)
Genetic	15q11-13 duplications, MECP2 mutations	Rare “de novo” variants in synaptic pruning genes
Perinatal	Prematurity, advanced parental age	Maternal autoantibodies against fetal brain proteins
Medical	Mitochondrial disease, seizure disorders	Early-life gut dysbiosis (microbiome imbalance)
Environmental	Prenatal exposure to valproate	High-dose antibiotic exposure in the first 18 months
Phenotypic	Significant language delay prior to loss	Early motor coordination “clumsiness”

This table integrates both well-established and emerging evidence, reflecting findings from large cohort studies and recent 2025 research.