Use of DNA probes in detecting carriers of Duchenne muscular dystrophy: selected case studies.

Detection of Duchenne muscular dystrophy carriers by genetic analysis is illustrated by four case studies. The technique is most useful in obligate families, in excluding carrier status in isolated cases, and in families in which the affected child demonstrates a molecular deletion. A major limitation of this technique is that the accuracy of carrier status in isolated (i.e., no family history) cases is limited by the probability that the affected child may represent a new mutation. To improve the carrier risk estimate generated by the DNA data, particularly in isolated cases, we suggest that measuring creatine kinase activities in the serum and performing the genetic analysis on the nonaffected males may be helpful.