title: Reduction in size of the myotonic dystrophy trinucleotide repeat mutation during transmission.
abstract: Myotonic dystrophy (DM) is an autosomal-dominant disorder that affects 1 in 8000 individuals. Amplification of an unstable trinucleotide CTG repeat, located within the 3' untranslated region of a gene, correlates with a more severe DM phenotype. In three cases, the number of CTG repeats was reduced during the transmission of the DM allele; in one of these cases, the number was reduced to within the normal range and correlated at least with a delay in the onset of clinical signs of DM. Haplotype data of six polymorphic markers in the DM gene region indicate that, in this latter case, two stretches of the affected chromosome had been exchanged with that region of the wild-type chromosome.
authors.affiliation: Department of Microbiology and Immunology, University of Ottawa, Canada.
authors.forename: K L
authors.initials: KL
authors.lastname: O'Hoy
authors.forename: C
authors.initials: C
authors.lastname: Tsilfidis
authors.forename: M S
authors.initials: MS
authors.lastname: Mahadevan
authors.forename: C E
authors.initials: CE
authors.lastname: Neville
authors.forename: J
authors.initials: J
authors.lastname: Barceló
authors.forename: A G
authors.initials: AG
authors.lastname: Hunter
authors.forename: R G
authors.initials: RG
authors.lastname: Korneluk
mesh_terms: D000328:Adult; D000367:Age Factors; D000483:Alleles; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C / Q000235:genetics; D001483:Base Sequence; D002888:Chromosomes, Human, Pair 19; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D005260:Female; D005799:Genes, Dominant; D006239:Haplotypes; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D009223:Myotonic Dystrophy / Q000235:genetics* / Q000503:physiopathology; D009838:Oligodeoxyribonucleotides; D010375:Pedigree; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid
chemical_list: D053304:Apolipoprotein C-II; D001056:Apolipoproteins C; D009838:Oligodeoxyribonucleotides; D004247:DNA