Non-progressive familial congenital cerebellar hypoplasia

A syndrome is reported of congenital non-progressive, gradually slightly improving, ataxia in 3 out of 5 male sibs, issues of a first-order consanguineous mating. Additional characteristic features included: moderate microcephaly, generalised muscle weakness and hypotonia, nystagmus, and moderate mental retardation. A pyramidal syndrome of hyperreflexia and Babinski signs, without any spasticity, became manifest in the 2nd or 3rd year of life. In all three, the caudal part of the vermis was absent, the enlarged IVth ventricle opening up via Magendie's foramen 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 analysed and the developmental pathogenetic mechanisms likely to produce the typifying distribution of aplasia are indicated.