Identification of a novel ADAR mutation in a Chinese family with dyschromatosis symmetrica hereditaria (DSH)

Dyschromatosis symmetrica hereditaria (DSH [MIM 127400]) is characterized by the presence of hyperpigmented and hypopigmented macules mostly on the dorsal aspects of the extremities. Genetic studies have identified mutations in the ADAR gene, encoding double-stranded RNA-specific adenosine deaminase, to be responsible for this disorder. Here, we found a novel deletion mutation in the ADAR gene, 2929delA, in a Chinese family with DSH. This mutation is located in codon 977 (AGC-->GC), and leads to a frameshift and truncated protein of 250 amino acids with 76 novel amino acids prior to a premature stop codon. The truncated ADAR is predicted to lack the ADEAMc (tRNA-specific and double-stranded RNA adenosine deaminase) domain. This study should be useful for genetic counseling and prenatal diagnosis for affected families and in expanding the database on ADAR gene mutations in DSH.