Lethal familial fetal akinesia sequence (FAS) with distinct neuropathological pattern: type III lissencephaly syndrome.

We report on a distinct pattern of primary central nervous system (CNS) degeneration affecting neuronal survival in the brain and spinal cord in 5 fetuses with fetal akinesia sequence (FAS). This neuropathological pattern is characteristic of a lethal entity that we propose calling type III lissencephaly syndrome. Parental consanguinity and the recurrence in sibs support a genetic cause. The mechanism of neuronal death is not yet understood; abnormal apoptosis and/or deficiency in neurotropic factors may be considered possible causes.