A novel form of lethal microcephaly with simplified gyral pattern and brain stem hypoplasia.

We report on four patients from the same family affected by a lethal form of autosomal recessive microcephaly of prenatal onset. Symptoms include low birth-weight and length with disproportionately small head, fetal distress, apnea, seizures and facial features reminiscent of Amish microcephaly and Bowen-Conradi syndrome. Brain imaging revealed a simplified gyral pattern with normal to slightly thinned cortical gray matter, thin corpus callosum, mild brainstem and cerebellar hypoplasia. No abnormalities of the internal organs, eye, or skeleton, and no striking dysmorphic facial features were found to be associated with this syndrome. All patients died within hours to weeks after birth following severe apnea attacks and central hypoventilation. Recessive primary microcephaly with lethality in early infancy is rarely reported. The patients described here do not resemble any other published cases of such clinical severity and the locus for the only reported early lethal microcephaly gene found in Amish families was excluded. Therefore, this appears to be a distinct genetic cause of lethal microcephaly.