title: Monozygotic female twin carriers discordant for the clinical manifestations of Duchenne muscular dystrophy.
abstract: We studied twin sisters, in their sixth decade, who were obligate carriers of Duchenne dystrophy. One had a slowly progressing limb-girdle myopathy since her mid-20s. The other sister showed no evidence of neuromuscular disease by history or on physical examination but had high serum CK values and degeneration and regeneration of fibers in a muscle biopsy. Otherwise, they were phenotypically identical, karyotypically normal females with cytogenetically normal X-chromosomes. Based on red cell and HLA loci antigen determinations, there was a 99.2% probability that they were monozygotic. The mutant gene segregating in the family is probably linked to the Xp21 DNA marker pERT87.
mesh_terms: D004200:Diseases in Twins; D005260:Female; D008040:Genetic Linkage; D006579:Heterozygote; D006801:Humans; D007621:Karyotyping; D008875:Middle Aged; D009136:Muscular Dystrophies / Q000235:genetics* / Q000503:physiopathology; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length; D014427:Twins; D014430:Twins, Monozygotic; D014960:X Chromosome