Potential pitfalls in using DNA probes to counsel Duchenne and Becker muscular dystrophy families

Although the accuracy in prenatal diagnosis and carrier detection with DNA probes in families with Duchenne and Becker's muscular dystrophies is very high, various factors limit the accuracy of these probes in many families. We report four potential pitfalls, ie, intragenic recombination, genetic heterogeneity, germline mosaicism, and an evolving genetic defect encountered in a population of Duchenne and Becker families, and describe a strategy to incorporate these factors into genetic counseling.