Failure of Fetal Creatine Phosphokinase as a Diagnostic Indicator of Duchenne Muscular Dystrophy

To the Editor: We had previously reported the potential usefulness of fetal plasma creatine phosphokinase for the in utero diagnosis of Duchenne muscular dystrophy.¹ Table 1 shows our findings in an enlarged series of male fetuses at risk for Duchenne muscular dystrophy, including three false-negative diagnoses (Patients 4, 17 and 22) and one probable true-positive diagnosis (Patient 2). Some couples had elected to participate in the research protocol with the intent of continuing their pregnancies. Other couples had decided to terminate their pregnancies regardless of the test results, and we sampled fetal blood in conjunction with intra-amniotic prostaglandin F_2α injection. Patient.