Analysis Of The Mutations Of Adarl Gene In The Patients With Dyschromatosis Symmetrica Hereditaria

Background Dyschromatosis symmetrica hereditaria(DSH),also called reticulate acropigmentation of Dohi, is a rare autosomal dominant pigmentary genodermatosis. It is characterized by a mixture of hyperpigmented and hypopigmented macules of various ephelides and no hypopigmentation symptoms. especially serious in the back of the hand and foot,it can also extends to the forearm and calf. These abnormalities are otherwise asymptomatic and do not affect the general health of the patients. In2003, the DSH locus has been mapped to chromosome1q21, in the same year, Pathogenic mutations were identified in the double-strand RNA-specific adenosine deaminase (ADAR) gene that is located in1q21.3by Japanese scholars Miyamura etc. ADAR spans30kb and contains15exons. It encodes RNA-specific adenosine deaminase composed of1226amino acid residues. So far, there has been reported more than100mutations, including mis-sense mutations, splice-site mutations, frame-shift mutations, nonsense mutations. Previous reports indicated that most ADAR gene mutations were located in the9-14exons, corresponding to the886-1221codon, of about30%of the full-length ADAR. So we think this region may be the most likely mutation region.Objective To detect the mutations in ADAR gene of patients to confirm clinical diagnosis as well as the pathogenic gene underlying dyschromatosis symmetrica hereditaria。Methods Genomic DNA was extracted from peripheral blood by routine phenol-chloroform methods from2affected and1unaffected individuals in the family. Polymerase chain reaction (PCR) amplification of the ADAR gene was performed spanning all15exons and flanking sequences of ADAR gene and direct sequencing was performed to screen the mutations in ADAR gene.Results No mutations were identified by direct sequencing of all15exons and flanking sequences.Conclusions No mutations were found in all15exons and flanking sequences, we presumed the causal gene may be located in intron regions, promoter regions of5’or other gene. Further studies need to be continued.