Two Novel and Two Recurrent Variants of the ADAR1 Gene in Three Chinese Families with Dyschromatosis Symmetrica Hereditaria

Purpose: Dyschromatosis symmetrica hereditaria (DSH) is a rare autosomal dominant inherited pigmentary dermatosis. The gene responsible for DSH has been identified as adenosine deaminase acting on RNA1 ( ADAR] ). This study aimed to identify the causative variants in the ADAR] gene in three Chinese families with DSH. Patients and Methods: Data and blood samples were collected from three Chinese families with DSH. Whole-exome and Sanger sequencing were performed to detect pathogenic gene mutation in the patients. Bioinformatics tools were used to predict the pathogenicity of the variants. Results: Four heterozygous ADAR] variants were identified, including two novel missense variants c.2369G>C (Arg790Pro), and 503C>T (Pro168Leu), and two previously reported variants: c.3232C>T(R1078C), and c.1472C>G (p.S491X). The novel c.503C>T variant was predicted as "deleterious" (score =-2.704) by PROVEAN, and "probably damaging" (score = 1) by PolyPhen2. The other novel variant c.2369G>C was also predicted as "deleterious" (score =-4.167) by PROVEAN, "probably damaging" (score = 1) by PolyPhen2, and "disease-causing" (p = 0.999) by Mutation Taster. Conclusion: Two novel ADAR] variants were found in Chinese patients with DSH. This research has expanded the ADAR] gene database for DSH, enhancing our comprehension of the underlying mechanisms.