Congenital ataxia of parietal origin? Report of two cases.

Congenital cerebellar ataxia is usually thought to be of cerebellar origin. We report two children with congenital cerebellar ataxia, in whom neuroimaging investigations suggest the possibility of a parietal etiology. The two boys showed hypotonia, delayed motor and cognitive development followed by marked, truncally pronounced ataxia. In one case infantile spasms were treated successfully with adrenocorticotropic hormone, although in follow-up the child suffered from occasional seizures. Magnetic resonance imaging showed in one case parieto-occipital pachygyria and in the other there was marked pachygyria, most pronounced over the parieto-occipital area. In both children cerebellar structures were normal. Cerebello-parietal connections are known to be responsible for acquired parietal limb ataxia. Although not proven, parietal lesions are the most likely etiology of congenital cerebellar ataxia in these two children. Therefore, cerebral, especially parietal pathology must be considered in children with congenital ataxia.