Localisation of the endpoints of deletions in the 5′ region of the duchenne gene using a sequence isolated by chromosome jumping

We have used chromosome jumping technology to move from within a large intron sequence in the Duchenne muscular dystrophy (DMD) gene to a region adjacent to exons of the gene. The single copy jump clone, HH1, was used to characterise deletions in patients previously shown to be deleted for DNA markers in the 5′ end of the gene. 12 out of 15 such patlents have breakpoints which lie between HH1 and the genomic locus J-47. Thus the vast majority of the deletions in these patients have proximal breakpoints in a similar region distal to the 5′end of the gene. HH1 was mapped with reapect to the X;1 translocatlon in a DMD female and was shown to lie at least 80 kb from the starting point of the chromosome jump, HIP25.