High resolution deletion breakpoint mapping in the DMD gene by whole cosmid hybridization.
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Blonden LA, den Dunnen JT, van Paassen HM, Wapenaar MC, Grootscholten PM, Ginjaar HB, Bakker E, Pearson PL, van Ommen GJ
High resolution deletion breakpoint mapping in the DMD gene by whole cosmid hybridization.
Nucleic Acids Res. 1989 Jul 25;17(14):5611-21. doi: 10.1093/nar/17.14.5611.
- PubMed ID
- 2569720 [ View in PubMed]
- Abstract
The locus DXS269 (P20) defines a deletion hotspot in the distal part of the Duchenne Muscular Dystrophy gene. We have cloned over 90 kilobase-pairs of genomic DNA from this region in overlapping cosmids. The use of whole cosmids as probes in a competitive DNA hybridization analysis proves a fast and convenient method for identifying rearrangements in this region. A rapid survey of P20-deletion patients is carried out to elucidate the nature of the propensity to deletions in this region. Using this technique, deletion breakpoints are pinpointed to individual restriction fragments in patient DNAs without the need for tedious isolation of single copy sequences. Simultaneously, the deletion data yield a consistent restriction map of the region and permit detection of several RFLPs. A 176 bp exon was identified within the cloned DNA, located 3' of an intron exceeding 150 Kb in length. Its deletion causes a frameshift in the dystrophin reading frame and produces the DMD phenotype. This exon is one of the most frequently deleted exons in BMD/DMD patients and its sequence is applied in a pilot study for diagnostic deletion screening using Polymerase Chain Reaction amplification.