RESUMO
<p><b>OBJECTIVE</b>To detect the heterogeneity of mitochondrial DNA (mtDNA) in black and white hair of patients with type 2 diabetes.</p><p><b>METHODS</b>MtDNA was extracted from the hair shaft of the patients to amplify two target DNA fragment from mtDNA coding region and control region using PCR. The differences in the heterogeneity in the target DNA fragment was analyzed between diabetic patients and the control group with denaturing high-performance liquid chromatography (DHPLC).</p><p><b>RESULTS</b>In the control subjects and diabetic patients, the mtDNA heterogeneity in the black hair was 3% and 10% in 20-45 year-old groups and 9% and 17% in 45-70 year-old groups, as compared to 9%, 20%, 21%, and 40% in the white hair, respectively. The mtDNA heterogeneity in the black and white hair was both higher in the diabetic patients than in the control subjects of the same age group, and was also higher in older age subgroups in both control and diabetic groups (P<0.05). The white hair mtDNA showed a significantly higher heterogeneity than the black hair mtDNA in the two age groups of diabetic patients and in 45-70 year-old control group (P<0.05).</p><p><b>CONCLUSION</b>The mtDNA heterogeneity in the hair increases in type 2 diabetic patients and show an association with aging.</p>