Gene deletions in Japanese patients with Duchenne and Becker muscular dystrophy

Abstract

Summary Thirty-eight unrelated Japanese patients with Duchenne and Becker muscular dystrophy (DMD and BMD) have been investigated with the DMD eDNA probes. The 14-kb DMD eDNA was subdivided into 6 subclones and HindlIl-digested DNAs were analyzed by Southern blotting. Out of 38 unrelated patients, 14 showed a deletion of one or several of the exon-containing HindlII fragments (36.8 ~). These corresponded to 50 ~o (9/18) of BMD patients and 25 ~ (5/20) of DMD patients, and the position and extent of deletions were mapped and proved to be more heterogeneous in DMD than in BMD. Both ends of deletions detected in probe 1-2a were common to all six BMD patients without the maintenance of reading frame of messenger RNA, and 5' ends of deletions in probe 5b-7 were also common but maintained in frame in three BMD patients. The phenotypic-specific deletion in Japanese BMD patients has existed in the 5' end of the DMD gene, although its apparently similar deletion produced a wide range of clinical courses (BMD phenotype). There was no tight correlation between clinical severity and presence or absence of deletion in DMD or BMD.

DNA analysis of Duchenne and Becker muscular dystrophy using pERT87 genomic probes and dystrophin cDNA probes

“…Deletions were detected in 72~o (13/18) of the DMD patients and in the one BMD patient. This detection rate was rather higher than that of 25~ in DMD and 50~ in BMD for the Japanese population as a whole (Asano et al, 1990), resembling the high detection rate in Caucasians ( Koenig et al, 1987). The discrepancy might be explained by our small sample size--especially for BMD (one case).…”

“…Submicroscopic deletions were reportedly detected in about 60 ~o of DMD/BMD patients using such cDNA probes (Koenig et al, 1987;Forrest et al, 1987;Read et al, 1988;Worton and Thompson, 1988;Darras et al, 1988;Lieehti-Gallati et al, 1989). However, sufficient data has not been accumulated regarding RFLPs and deletion studies in Japanese DMD/BMD families (Akita et al, 1987;Sugino et al, 1989;Asano et al, 1990).…”