Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0162671 (MELAS)
 587 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the prevalence of mitochondrial gene mutations in subjects with insulin-dependent diabetes mellitus (IDDM) in a Chinese population living in Taiwan. Eighty-four subjects with insulin-dependent diabetes mellitus and 105 unrelated normal controls were recruited in the present study. Both an A-to-G mutation at position 3243 and a mutation at position 8,344 of the mitochondrial DNA were screened by polymerase chain reaction-restriction fragment length polymorphism methods and confirmed by direct DNA sequence analysis. The insulin secretory response was assessed by the C-peptide response to glucagon administration. Among 84 IDDM patients, two (2.4%) subjects were found to carry the 3,243 nucleotide pair (np) mutation. There was no np 8,344 mutation in this series. Of the two subjects carrying a mitochondrial gene mutation, case 1 manifested initially as gestational diabetes mellitus. Manifestation of case 2 was consistent with MELAS, a syndrome of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes. The pancreatic beta cell reserve was reduced, as the glucagon-stimulated C-peptide response was very low in these two cases. HLA genotyping studies revealed that case 2 carried DRB1*0301-DQA1*0501-DQB*0201/ DRB1*0405-DQA1*0301-DQB1*0302, which was the most susceptible genotype to IDDM in our population. Anti-GAD65 antibody was also positive in this patient. In addition to the nuclear genes, a defective mitochondrial gene might contribute to some of the clinical cases with IDDM.
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PMID:Mitochondrial gene mutations in patients with insulin-dependent diabetes mellitus in Taiwan. 883 Mar 30

Mitochondrial DNA (mtDNA) defects are associated with a number of human disorders. Although many occur sporadically, maternal transmission is the hallmark of diseases due to mtDNA point mutations. The same mutation may manifest strikingly different phenotypes; for example, the A to G substitution at np 3243 was first reported in patients with mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (the MELAS syndrome), but is also found in patients with diabetes and deafness. Here we present a case of gestational diabetes, deafness, premature greying, placenta accreta and Wolff-Parkinson-White (WPW) syndrome associated with a mtDNA mutation. Although this is the first report of such an association, study of 27 other patients with WPW syndrome failed to confirm that this mtDNA mutation is a common cause of such pre-excitation disorders.
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PMID:Identification of mtDNA mutation in a pedigree with gestational diabetes, deafness, Wolff-Parkinson-White syndrome and placenta accreta. 1109 78

Maternal diabetes associated with neural deafness is designated as MIDD (maternal inherited diabetes and deafness); it is linked to a A3243G tRNA leucine gene mutation. The disease course is progressive and involvement of other systems is frequent. In most cases, macular pattern dystrophy is present. Muscular lesions are characteristic of mitochondrial myopathies. Mitochondrial abnormalities have also been observed in pancreas, heart, kidney, smooth muscle of the digestive tract with variable heteroplasmy levels. MIDD may present as a single syndrome or is part of MELAS or Kearns-Sayre syndrome.
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PMID:[Diabetes and mitochondrial cytopathies: pathological studies]. 1632 55