title: A new point mutation associated with mitochondrial encephalomyopathy.
abstract: Point mutations in the mitochondrial gene tRNA leucine(UUR) have been associated with maternally inherited mitochondrial myopathies including the MELAS syndrome (Mitochondrial Myopathy Encephalopathy Lactic acidosis and Stroke-like episodes). We describe a further mutation in tRNA leucine(UUR) in a patient with mitochondrial encephalomyopathy, pigmentary retinopathy, dementia, hypoparathyroidism and diabetes mellitus. The mutation was heteroplasmic in the proband's blood (30%) and muscle (76%); it was present at high levels in the proband's affected mother (50% in muscle), and at low levels (< 10%) in blood, muscle and fibroblasts of an unaffected sister. The mutation was not found in 121 normal controls or 35 other patients with mitochondrial disorders. The mutation is at a highly conserved position in the tRNA molecule, close to the 3,243 mutation which is associated with more than 80% of MELAS cases. Further more, both mutations lie within a possible transcriptional control region. This finding adds further support to the evidence that mutations in this region and in other mitochondrial tRNA genes may cause disease.
authors.affiliation: Department of Paediatrics, University of Oxford, John Radcliffe Hospital, UK.
authors.forename: K J
authors.initials: KJ
authors.lastname: Morten
authors.forename: J M
authors.initials: JM
authors.lastname: Cooper
authors.forename: G K
authors.initials: GK
authors.lastname: Brown
authors.forename: B D
authors.initials: BD
authors.lastname: Lake
authors.forename: D
authors.initials: D
authors.lastname: Pike
authors.forename: J
authors.initials: J
authors.lastname: Poulton
mesh_terms: D000328:Adult; D000818:Animals; D001483:Base Sequence; D001706:Biopsy; D002648:Child; D017931:DNA Primers; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D017241:MELAS Syndrome / Q000235:genetics; D008297:Male; D008875:Middle Aged; D017237:Mitochondrial Encephalomyopathies / Q000235:genetics* / Q000473:pathology; D017240:Mitochondrial Myopathies / Q000235:genetics; D008969:Molecular Sequence Data; D009035:Mothers; D009132:Muscles / Q000473:pathology; D009690:Nucleic Acid Conformation; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012356:RNA, Transfer, Leu / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D017931:DNA Primers; D012356:RNA, Transfer, Leu