Calf myopathy with a twist.

The traditional clinical criteria for identifying a manifesting Duchenne carrier are a positive family history, proximal limb weakness, calf hypertrophy, high serum creatine kinase. We describe a 52-yr-old woman with history of 1 1/2 yr of progressive wasting and weakness of the left calf and marked elevation of serum creatine kinase. Although her quadriceps was clinically silent, it showed mild alterations on ultrasound, computerized tomography and biopsy, and some abnormalities in dystrophin immunostaining, suggesting a manifesting carrier of the dystrophin gene. Given the enormous variability of manifestations of the Duchenne variant in females, we suggest that great care must be exercised in ruling out this genetic disorder.