The clinical and genetic characteristics of 63 patients with agenesis of the corpus callosum (ACC) are reported from the Scientific Institute “E Medea,” Italy. Of 1753 patients admitted (1998-2001) and having neuroimaging, 63 (3.5%) showed ACC. Mean age was 2 years 7 months (range 1-25 yrs); 39 were male and 24 female. Thirty patients (47%) had complete ACC and 33 (53%) partial agenesis. Associated nervous system malformations were found in 10 (33%) patients with complete ACC (usually affecting the cortex) and in 14 (42%) with partial ACC (involving the posterior fossa). Non-CNS malformations, including craniofacial, cardiac and skeletal, were present in 41 (65%) patients; 21 (33%) with known syndromes (eg Aicardi (2), Sotos (3), tuberous sclerosis (1)). Seven patients had chromosomal abnormalities, and 3 had subtelomeric rearrangements. Mental retardation was present in 52 (83%), neuromotor inpairment in 58 (92%), and epilepsy (35%). ACC is manifested by a broad range of clinical manifestations. 
COMMENT. ACC has various manifestations, and the prognosis is also variable. ACC is an isolated finding in 17% cases. Multiple malformations, CNS and non-CNS, are present in more than two third of cases. A presentation with craniofacial abnormalities (macrocephaly, hypertelorism, depressed nasal bridge) is sufficiently frequent to warrant neuroimaging. A complete ACC is associated with malformations of cortical development whereas partial ACC is more frequently correlated with posterior fossa anomalies.
The autopsy case of a boy with arthrogryposis multiplex congenita, associated with complete ACC and dentato-olivary dysplasia is reported from Japan .