Four novel mutations of ADAR1 in Chinese patients with dyschromatosis symmetrica hereditaria

Background: Novel mutations in adenosine deaminase acting on RNA 1 gene (ADAR1) are responsible for dyschromatosis symmetrica hereditaria (DSH). DSH patients display a mixture of hyperpigmented and hypopigmented macules on the dorsal aspects of the extremities, and freckle-like macules on the face.

Aims: To provide new evidence for further study of the etiopathogenisis of DSH.

Methods: Genomic DNA was extracted and used as a template for the polymerase chain reaction (PCR) amplification of all 15 coding exons as well as intron-exon boundaries of ADAR1. The PCR products were sequenced directly.

Results: We identified eight mutations of ADAR1 in four Chinese pedigrees and four individual patients, which were c.2722G>T, p.(Asp908Tyr), c.1657delA, p.(Ser553fs), c.2563_2564delCT, p.(Leu855fs), c.526T>G, p.(Leu176Val) as well as four previously reported mutations c. 3363_3364insT, p.(Lys1122fs), c. 2865_2866delGT, p.(Val955fs), c.1630C>T, p.(Arg544X), and c.2894C>T, p.(Pro965Leu). In silico analysis predicted that all the mutations reported were pathogenic.

Limitations: We did not study how ADAR1 played its role in DSH. So, the exact pathogenic mechanism of ADAR1 in DSH patients wasn't clarified in this study.

Conclusion: We found four novel ADAR1 mutations in this study. Our results enlarge the database on ADAR1 mutations associated with DSH.