Carrier detection in Becker muscular dystrophy using creatine kinase estimation and DNA analysis

Serum creatine kinase levels in 39 control females and 59 obligate carriers of Becker muscular dystrophy (BMD) have been used to construct likelihood ratios for carrier detection. In 24 possible carriers of BMD, analysis of DNA with X chromosome specific DNA probes linked to the dystrophy gene, has been used in conjunction with creatine kinase measurement to calculate final risk estimates of carrier status. Incorporation of information from probe genotype into the Bayesian calculation, enables a substantially lower risk to be deliniated for some possible carriers of the BMD gene. Thus, although the existing DNA probes are not sufficiently closely linked to BMD to be used in prenatal diagnosis, they can make a major contribution to genetic counselling by refining the estimated probability of carrier status.