ANALYSIS OF SCOTTISH DUCHENNE AND BECKER MUSCULAR-DYSTROPHY FAMILIES WITH DYSTROPHIN CDNA PROBES

One hundred and thirty-two Scottish families, representing the majority of currently known cases in this country with at least one living subject affected by DMD (110) or BMD (22), were studied with a series of cDNA probes excluding the 3' region of the gene (probes 10-14). Using mainly HindIII digested DNA from affected males, 89 patients showed deletions which ranged from 1 to 32 HindIII fragments in size. Two patients were also detected with exon duplications. Abnormalities were found to be particularly concentrated in the area of probe cDNA 8, with 56 patients being deleted for at least one of the fragments detected by this probe. A second smaller concentration of deletions was found with probe 1-2a which showed 16 deletions and two duplications. The endpoints of cDNA deletions or duplications were determined with a maximum variability of one HindIII fragment in 83 patients, while the remaining eight patients had a single deletion endpoint defined. The deletions found in two of our patients appear to conflict with the previously stated exon order at the 5' end of the gene. Although no specific deletion patterns were apparent for DMD, the deletions found in 13 of the BMD patients all included the most proximal (10 kb) fragment detected by probe 8.