Carrier detection of Duchenne/Becker muscular dystrophy by using fluorescent linkage analysis in Taiwan

The mutation analysis of Duchenne/Becker muscular dystrophy (DMD/BMD) is made difficult by the size and structure of the gene. The dystrophin gene deletion is responsible for 45-58% of DMD/BMD cases in Taiwan. For the others, who have no deletions, carrier detection was performed by DNA linkage analysis. To determine frequencies of each allele and heterozygosity of each short tandem repeats (STR) marker, we analyzed 50 unrelated Taiwanese males and 50 unrelated Taiwanese females unaffected by DMD/BMD using ten fluorescently labeled intragenic markers (these ten being located in 5' terminus, intron 1, 44, 45, 48, 49, 50, 55-57 and 3' untranslated region of the human dystrophin gene). The predicted heterozygosity frequency is 46.7-88.3% in our study population and these STR markers are quite informative for linkage analysis. Using these ten intragenic STR markers, we analyzed 14 DMD/BMD families with 62 family members for carrier detection. Our retrospective study of DMD/BMD families highlights the informative power of STR haplotyping. In summary, STR analysis using (CA)n repeats within the human dystrophin gene is well suited for routine use in clinical laboratories engaged in linkage studies for carrier detection and prenatal diagnosis in DMD/BMD families.