Feasibility of short tandem repeats [STR] analysis for carrier detection and prenatal diagnosis in families with duchenne muscular dystrophy [DMD]

ABSTRACT

To determine the feasibility of Short tandem Repeats [STR] based linkage analysis for carrier detection and prenatal diagnosis [PND] in families having children affected with Duchemnne Muscular Dystrophy. Case series. Department of Chemical Pathology and Endocrinology in collaboration with Department of Molecular Biology, Armed Forces institute of Pathology [AFIP], Rawalpindi. From February 2007 to January 2008. six unrelated families with at least one affected child in each family who had characteristic features of DMD [index case]. PCR for Duchenne Muscular Dystrophy was carried out with STR based linkage analysis at introns 44, 46, 49 and 50 of DMD gene. Thermal cycling in TC-480 [Perkin Elmer] included 25 cycles each comprising 30 sec denaturation at 94 [degree sign] C, annealing at 62 [degree sign] C for 30 sec, extension at 65 [degree sign] C for 2 min. The final extension was done for 3 min. The amplified products were run on 8% nondenaturing polyacrylamide gel electrophoresis [PAGE] carried out at 200V for three hours on electrophoresis apparatus [Bio-Rad UK]. The gels were stained in silver nitrate. By comparing STR pattern of X-chromosome allele of index case with X-chromosome alleles of the mother, the diseased or affected X-chromosome was ascertained. Carrier detection and prenatal diagnosis was feasible with STR marker at intron 44 in DMD families. It was informative in 5 out of 6 DMD families. Carrier detection and PND by STR based linkage analysis is technically feasible in Pakistani families with DMD