Lethal X-linked microcephaly with dysmorphic features, bilateral optic pathway aplasia and normal eyes

We describe a family, consisting of two brothers and a maternal uncle who d ied of an apparently identical condition, within a few days of birth, sugge stive of an X-linked mode of inheritance. The propositus (the older sibling ) was investigated in detail and showed the following clinical features: mi crocephaly, facial dysmorphism, malformations of hands and feet, and crypto rchidism. Examination of the brain revealed arhinencephaly, a primitive gyr al pattern, arrested cortical maturation, absence of corticofugal tracts an d corpus callosum, agenesis of the optic pathway with preserved eyes and oc ulomotor system, absent auditory pathway, agenesis of the pars compacta of the substantia nigra and severe hypoplasia of the cerebellum and its connec tions. This family belongs to the group of X-linked microcephalies and has some features in common with the Juberg-Marsidi syndrome. The fact that the CNS abnormalities were incompatible with life and the facial dysmorphic fe atures were quite different makes it unlikely that the affected individuals in this family had Juberg-Marsidi syndrome. However, this does not exclude the possibility that more, restricted anterior induction defects may occur in some X-linked microcephalies such as Juberg-Marsidi syndrome resulting in prolonged survival.