We have studied a boy with acrocallosal syndrome and hypogenitalism. He was the offspring of double first cousins. He had unusual facial appearance, postaxial polydactyly with unilateral soft tissue syndactyly of fingers, mental retardation, and absence of corpus callosum. Findings in the present case were compared with those of previously reported cases. Other syndromes associated with agenesis of the corpus callosum must be differentiated. The main differences between the acrocallosal syndrome and the Greig syndrome are outlined with particular emphasis on digital anomalies. The acrocallosal syndrome is an autosomal recessive trait with variable expressivity. Hypogenitalism may be a presenting feature. Positive consanguinity provides further evidence for autosomal recessive inheritance.