Deletion of dystrophin exon 45 in DMD-BMT1 genomic DNA by PCR. (a) DNA amplification performed using primers to dystrophin exons 42–47. Genomic DNA samples are from an unaffected individual (+) or DMD-BMT1 skin fibroblasts (D). The negative water control (–) is present for each primer set. M, molecular weight markers. (b) Coamplification of dystrophin exons 40 (599 bp) and 45 (383 bp) from genomic DNA of an unaffected individual (lane 1), DMD-BMT1 purified T cells (lane 2), or myeloid cells (lane 3). W, water control. (c) Chromatograms of the DNA sequence analyses performed on the dystrophin exon 45 band amplified by PCR from DMD-BMT1 and his parents. DMD BMT-1 and his father are homozygous for A at nucleotide 143 upstream of exon 45, while the mother has a G in this position.