Recombination frequencies between Duchenne muscular dystrophy and intragenic markers in multigeneration families

Deletion screening is the initial step in carrier detection and prenatal diagnosis of Duchenne/Becker muscular dystrophy (DMD/BMD). More than 50% of DMD mutations are deletions, but if deletion analysis is uninformative, the next diagnostic step is linkage analysis. The problem with the linkage approach is that the DMD gene is very large and there is an average recombination frequency ( theta ) of approximately 5% between intragenic markers (pERT87 or XJ) and the region of the gene containing the DMA mutation. This means that basing prenatal diagnosis on intragenic probes is not completely satisfactory.