NONPROGRESSIVE CONGENITAL ATAXIAS

Congenital ataxias (CA) are rare, predominantly non-progressive syndro mes characterized by marked hypotonia, developmental delay followed by the appearance of ataxia. Most children show marked speech and cognit ive developmental problems. Non- progressive CA (NPCA) can be divided into pure CA without additional symptoms and syndromes with CA. Pure C A can be due to cerebellar malformations as (hereditary or non-heredit ary) cerebellar hypoplasia, Dandy Walker syndrome, or occasionally sup ratentorial abnormalities. Ataxic syndromes are less frequent, but mor e distinctive. There are syndromes (e.g. Joubert syndrome) where ataxi a is a cardinal feature and others where ataxia is only an occasional symptom. Acquired ataxias, due to congenital cytomegalovirus infection or perinatal problems, form a small third group. In about half of all cases with NPCA, aetiology and inheritance are still unknown. Diagnos is of NPCA is made by a typical history and careful clinical examinati on. Diagnosis of a more distinctive ataxic syndrome may be possible on clinical grounds. Neuroimaging with special attention to the posterio r fossa will aid accurate clinical classification. Early progressive a taxias require careful differentiation from other types. (C) 1998 Else vier Science B.V. All rights reserved.