Mitochondrial tRNA [Leu[UUR] gene mutation and maternally inherited diabetes mellitus in Pakistani population

ABSTRACT

Maternally Inherited Diabetes Mellitus and Deafness [MIDD] occurs due to the mutations in mitochondrial DNA [mtDNA]. The most common heteroplasmic point mutation reported, is in the tRNA [Leu[UUR] gene, i.e., A3243G, accompanied with deafness. The objectives of the present study were to determine whether the cause of MIDD in selected Pakistani population, is also the mutation of A3243G in mitochondrial tRNA [Leu[UUR] gene or not, and is there any genotype-phenotype correlation for the MIDD in this population. The present study was conducted in the Department of Biochemistry and Molecular Biology, Army Medical College, Rawalpindi, Pakistan, during the period November 2005 to November 2007. The patients and control subjects were randomly selected from the two cities; Rawalpindi and Multan [both rural and urban areas] and were divided into three groups. [1] Fifty patients with T2DM and maternal history with feature [s] of MIDD. [2] Fifty non-diabetic first-degree relatives of patients with T2DM. [3] Fifty non-diabetic controls with no maternal history of T2DM. The patients and control subjects were scanned for the detection of potential mutations in mitochondrial DNA tRNA [Leu[UUR] gene [np 3035-3456, 422 bp fragment]. On the basis of a polymerase chain reaction, electrophoresis and mtDNA sequencing along with insulin dependence, degree of deafness in patients and subjects, it is proved that there is no A-to-G mutation at np 3243 of mitochondrial leucine tRNA gene in any of the groups studied. Conclusion: It is concluded that in the Pakistani population, selected for the present study, the MIDD is not due to A3243G mutation in mitochondrial tRNA [Leu[UUR] gene