NONPROGRESSIVE FAMILIAL CONGENITAL CEREBELLAR HYPOPLASIA

A syndrome is reported of congenital non-progressive, gradually slight ly improving, ataxia in 3 out of 5 male sibs, issues of a first-order consanguineous mating. Additional characteristic features included: mo derate microcephaly, generalized muscle weakness and hypotonia, nystag mus, and moderate mental retardation. A pyramidal syndrome of hyperref lexia and Babinski signs, without any spasticity, became manifest in t he 2nd or 3rd year of life. In all three, the caudal part of the vermi s was absent, the enlarged IVth ventricle opening up via Magendie's fo ramen into the cisterna magna. The middle and rostral vermian parts as well as the sagittal paravermian parts of the cerebellar hemispheres were hypoplastic. The differential diagnosis of this syndrome is analy sed and the developmental pathogenetic mechanisms likely to produce th e typifying distribution of aplasia are indicated.