Type 2a fibre rhabdomyolysis in myoadenylate deaminase deficiency.

A 31-year-old woman developed an acute, potentially fatal rhabdomyolysis of undetermined origin. Muscle biopsy revealed selective lysis involving exclusively type 2a fibers. Myoadenylate-deaminase (MAD) deficiency was proven by a negative histochemical reaction as well as by an enzymatic biochemical determination. The significantly greater energetic dependence of type 2a fibres on MAD explains their selective damage. The patient's mother also suffers from a similar muscle disease of still unclarified origin.

Morphometric study of muscle in congenital idiopathic club foot.

In congenital idiopathic club foot gross morphological changes cannot be assessed in muscle tissue by conventional histopathological techniques. Since, however, recent studies have indicated the presence of neuromuscular anomalies with preponderance of Type 1 fibres in this condition, we have performed histochemical, morphometric and electron microscopic examinations in muscle biopsies of 23 patients with congenital idiopathic club foot deformity. The age of the patients varied between 6 weeks and 12 years, respectively. Muscle biopsy was taken mainly from the flexor group of the affected leg(s) during the surgical correction of the anomaly. No gross pathological changes could be found by histochemical analysis. Morphometric study, however, disclosed abnormalities in the composition of the fibre types. The most prominent change was the percentual increase in Type 1 and decrease in Type 2 fibres in almost all the cases. Electron microscopically, only minor fine structural changes could be found. Since these changes could be assessed soon after birth just as in the later course, they cannot be regarded as the consequence of the abnormal position of the leg. More probably, Type 1 fibre predominance is related etiologically to the congenital club foot deformity.