Prevalence and clinical characteristics of maternally inherited diabetes and deafness caused by the mt3243A > G mutation in young adult diabetic subjects in Sri Lanka

AbstractAims  The maternally inherited mt3243A > G mutation is associated with a variable clinical phenotype including diabetes and deafness (MIDD). We aimed to determine the prevalence and clinical characteristics of MIDD in a large South Asian cohort of young adult‐onset diabetic patients from Sri Lanka.Methods  DNA was available from 994 subjects (age of diagnosis 16–40 years, age at recruitment ≤ 45 years). Mutation screening was performed using a QRT‐PCR method on an ABI 7900HT system using sequence‐specific probes. Samples with heteroplasmy ≥ 5.0% were considered positive.Results  Nine (four males) mutation‐positive subjects were identified (prevalence 0.9%). They were diagnosed at a younger age (25.9 ± 4.8 years vs. 31.9 ± 5.6 years, P = 0.002) and were lean (body mass index [BMI] 18.7 ± 2.7 kg/m2 vs. 24.7 ± 4.0 kg/m2, P < 0.001) compared to NMCs. One mutation‐positive subject (11.1%) had metabolic syndrome, compared to 633 (64.3%) of NMCs. Insulin therapy within 6 months of diagnosis was used in four (44.0%) carriers compared to 6.9% of NMCs (P = 0.002). Combined screening criteria of any two of maternal history of diabetes, personal history of hearing impairment and family history of hearing impairment only identified five (55%) of the carriers, with a positive predictive value of 7.4%.Conclusions  The prevalence of mt3243A > G mutation among young adult‐onset diabetic subjects from Sri Lanka was 0.9%. Our study demonstrates that a maternal family history of diabetes and either a personal and/or family history of deafness only distinguish half of patients with MIDD from Sri Lankan subjects with young‐onset diabetes.