Cerebral gigantism: Apparent dominant inheritance

Since originally defined in 1964, over 80 cases of cerebral gigantism have appeared in the literature. Developmental features consist of large size at birth, accelerated growth in early childhood with an accompanying advanced bone age, normal sexual development and usually normal final adult stature. Variable degrees of mental retardation are present. Characteristic physical features include macrocrania, dolichocephaly, high arched platelet, prognathism, large hands and feet and an increased arm span. The etiology and pathogenesis are unknown and with the exception of single reported pairs of monozygotic twins, 1st cousins and sibs, all other reported cases have been sporadic. A genetic etiology has been suggested; however, a clear mode of inheritance has not been determined. A family in which cerebral gigantism appears to be inherited as a dominant trait is reported.