Analysis of "pure" congenital muscular dystrophies in thirty-eight cases. How different is the classical type 1 from the occidental type cerebromuscular dystrophy?

Congenital muscular dystrophies (CMD) are heterogenous in clinical and pathologic manifestations. The "pure" classical form includes cases without severe impairment of intellectual development (Type 1), and cases with normal or subnormal IQ which show white matter hypodensity on CT scan examination. This latter group is sometimes called the "occidental type cerebro-muscular dystrophy" (OCMD). In this study we report clinical and pathologic findings in 38 cases with pure CMD. Eighteen of them were classified as Type 1 and 20 as OCMD, following the neuroradiological work-up. Statistical analysis between the two groups were done for: age range, consanguinity, multiple joint contractures, maximal motor capacity, facial involvement, high CK, endomysial fibrosis, adiposis, fiber atrophy and necrosis. CK was significantly higher in the OCMD group. Though not statistically significant, multiple joint contractures and muscle fiber necrosis were seen in more OCMD patients. These parameters denoted severity. The results of electrophysiological tests did not show any statistical differences. In pure CMDs there is evidence for overlap between the two sub-groups. OCMD cases may tend to run a more severe course in the presence of significantly higher CK levels.