Identification Of Novel Mutations In The ADAR Gene Of Dyschromatosis Symmetrica Hereditaria (DSH)

Background Dyschromatosis symmetrica hereditaria (DSH) is a rare autosomal dominant pigmentary genodermatosis. It was first described by Komaya in 1924 and was coined DSH by Toyama in 1929. The onset of the disease is usually during infancy or early childhood and the skin lesions commonly stop spreading before adolescence and last for life. The male/female ratio was 1:1.This condition is characterized by a mixture of hyperpigmented and hypopigmented macules of various sizes mostly on the dorsal aspects of the extremities. On the face, the lesions resemble ephelides and no hypopigmentation appears. These abnormalities are otherwise asymptomatic and do not affect the general health of the patient. DSH has been reported mainly in Japan and China, although it occurs in families of every ethnic origin all over the world. Only a few similar cases from some parts of Asia and Europe have been reported. Miyamura et al. confirmed that the ADAR gene is responsible for DSH. ADAR belongs to a family of RNA-specific adenosine deaminase that represents one type of RNA editing enzyme and encodes double-stranded RNA-specific adenosine deaminase. ADAR catalyzes the deamination of adenosine in regions of dsRNA to form inosine (A to I editing), which is . read-out at the ribosome as guanosine. Up to now, a total of 43 ADAR gene mutations have been reported in DSH patients and no clear correlation between clinical features and genotypes has been established.Objective (1) To detect the ADAR gene mutations in Chinese patients with DSH and to analyze the genetic and clinical features of DSH in China. (2) To explore the correlation between the genotypes and phenotypes and to investigate the still-unknown mechanism. Methods (1) Five families and three sporadic cases with DSH were investigated from...