Clinical and genetic studies of muscular dystrophy in young girls

During the years 1971-81, we treated 7 girls with clinical features suggestive of Duchenne dystrophy. Muscle weakness developed at 1.5 or at 5-8 years and progressed rapidly. Two girls were in wheel-chairs in their teens. Muscle atrophy began in the proximal parts of the lower extremities and pseudohypertrophy of the calf occurred in all patients. Serum creatine phosphokinase (CPK) activity was moderately to highly elevated in all cases and EMG showed a moderate to marked myopathic pattern. Chromosomal studies showed normal finding in the five examined. Mental retardation (IQ 37-73) was present in four. Consanguinity was present in 3 out of the 7 cases. Two mothers showed elevated levels of CPK and myopathic patterns on EMG. In addition, one mother had slight muscle weakness at the age of 42 and another had prominent pseudohypertrophy of the calf. Sex-linked recessive inheritance might be considered here, because carriers of autosomal recessive type never showed elevated levels of CPK or mild myopathic symptoms. The other five of our seven might be cases of autosomal recessive inheritance, because the mothers had normal serum CPK levels and in 2 families there was a consanguinity.