USE OF SERUM CREATINE-PHOSPHOKINASE IN GENETIC-COUNSELING FOR DUCHENNE MUSCULAR-DYSTROPHY .2. REVIEW OF METHODS OF ASSAY AND FACTORS WHICH MAY BE RELEVANT IN THE INTERPRETATION OF SERUM CREATINE-PHOSPHOKINASE ACTIVITY

Several methods of CPK assay are compared and some factors which may affect serum CPK activity and which may be relevant to genetic counseling for carriers of DMD are discussed. We conclude from the published material that, for practical purposes, normal daily activity, the stage of the menstrual cycle and the use of the contraceptive pill do not affect CPK activity. CPK activity is higher in males than females and higher in Blacks than Whites, and these factors should be considered in the choice of controls for studies on this subject. CPK activity may be lowered during pregnancy; it appears to rise as the day progresses; and the effect of advancing age is not yet clear. Although other methods of diagnosing carriers have been suggested, for the present the CPK will probably remain the principal corroborative test for this purpose, and the various factors which may affect CPK activity should be considered in its interpretation. © 1979.