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World J Respirol. Nov 28, 2014; 4(3): 26-30
Published online Nov 28, 2014. doi: 10.5320/wjr.v4.i3.26
Update on diagnosis and treatment of pulmonary alveolar microlithiasis
Hui-Ying Wang, Ni-Ya Zhou, Xu-Yan Yang
Hui-Ying Wang, Ni-Ya Zhou, Department of Allergy, the Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, Zhejiang Province, China
Xu-Yan Yang, Department of Rheumatology, the Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, Zhejiang Province, China
Author contributions: Wang HY is responsible for the design and writing; Zhou NY is responsible for the data collecting; Yang XY attends the paper design.
Supported by Zhejiang Provincial Science and Technology Project, No. 2011C37073
Correspondence to: Hui-Ying Wang, MD, PhD, Department of Allergy, the Second Affiliated Hospital, College of Medicine, Zhejiang University, 88 Jiefang Road, Hangzhou 310009, Zhejiang Province, China. w_huiying@yahoo.com
Telephone: +86-571-87783267 Fax: +86-571-87783516
Received: June 25, 2014
Revised: September 15, 2014
Accepted: September 17, 2014
Published online: November 28, 2014
Abstract

Pulmonary alveolar microlithiasis (PAM) (MIM265100) is a rare disease characterized by the diffuse deposit of microlithiasis in alveolar spaces. PAM could occur worldwide with high prevalence in Asia and Europe. Familial occurrence indicates its autosomal recessive trait and the SLC34A2 gene was identified as the responsible gene for the disease. In spite of the versatile mutation sites in patients from other countries, exon 7 and exon 8 might be the most liable gene in Chinese and Japanese patients. Most mutations caused the premature termination of proteins and produced truncated proteins, leading to the blocking of the recycling and degrading of outdated surfactant which is full of phospholipids. The most outstanding clinical feature of PAM is the discrepancy between the paucity of symptoms and the degree of pulmonary involvement. Diagnosis is easy to establish based on typical chest radiograph image and nuclear medicine improves its early diagnosis and active evaluation. Pathology of the unique intra-alveolar lamellar microliths gives strong support for diagnosis. No effective treatment is considered valid currently. However, lung transplantation is effective for advanced-stage patients, and long term treatment of disodium etidronate seems promising.

Keywords: Pulmonary alveolar microlithiasis, SLC34A2, Mutation, Chest computed tomography, Treatment

Core tip: Pulmonary alveolar microlithiasis (PAM) is a rare disease and lack of enough acknowledgements. The present review provides a comprehensive description on the latest progress in the genotype and treatment of PAM. SLC34A2 is identified as the responsible gene and its mutation in patients from different countries has showed versatile symbols, whilst Chinese and Japanese patients only involved exon 7 and exon 8. The diagnosis of PAM could be established on typical chest radiograph image. Though currently no effective regimens are valid to cure the diseases, long term treatment of disodium etidronate seems promising.