Targeted next-generation sequencing identification of mutations in patients with disorders of sex development. Issue 1 (December 2016) - Dong, Yanling
Abstract Background The identification of causative mutations is important for treatment decisions and genetic counseling of patients with disorders of sex development (DSD). Here, we designed a new assay based on targeted next-generation sequencing (NGS) to diagnose these genetically heterogeneous disorders. Methods All coding regions and flanking sequences of 219 genes implicated in DSD were designed to be included on a panel. A total of 45 samples were used for sex chromosome dosage validation by targeted sequencing using the NGS platform. Among these, 21 samples were processed to find the causative mutation. Results The sex chromosome dosages of all 45 samples in this assay were concordant with their corresponding karyotyping results. Among the 21 DSD patients, a total of 11 mutations inSRY, NR0B1, AR, CYP17A1, GK, CHD7, andSRD5A2 were identified, including five single nucleotide variants, three InDels, one in-frame duplication, oneSRY -positive 46, XX, and one gross duplication with an estimated size of more than 427, 038 bp containingNR0B1 andGK . We also identified six novel mutations: c.230_231insA inSRY, c.7389delA inCHD7, c.273C>G inNR0B1, and c.2158G>A, c.1825A>G, and c.2057_2065dupTGTGTGCTG inAR . Conclusions Our assay was able to make a genetic diagnosis for eight DSD patients (38.1 %), and identified variants of uncertain clinical significance in the other three cases (14.3 %). Targeted NGS is therefore a comprehensive and efficient method to diagnose DSD. This work also expands the pathogenic mutation spectrum of DSD.