The identification of the carrier state in Duchenne muscular dystrophy is of prime importance for genetic counseling.

The presence of elevated serum creatine kinase(CK), lactic dehydrogenase(LDH), aspartate transaminase(AST) and alanine trasaminase(ALT) levels in 11 obligate carriers of Duchenne muscular dystrophy, 26 possible carriers and 36 carrier suspects were compared with these levels in 195 female normal controls.

Only serum CK levels among 4 serum enzymes were significantly elevated in each carrier group compared with the normal control group.

A negative correlation was found between age and the CK levels in normals, but not in any of the carrier groups. The CK levels in each carrier group showed non-statistical significant tendency to decrease with aging.

There were elevated CK levels in 63.6% of the obligate carriers, 26.9% of the possible carriers and 22.2% of the carrier suspects.

Higher CK levels were found in the carrier suspects younger than 10 years of age.