P 916. Lissencephaly and Prolonged Survival of a Male Infant with MICPCH and a Noval Mutation in the CASK Gene, Xp11.4

Background: The calcium/calmodulin-dependent serine protein kinase gene (CASK, chromosome Xp11.4, MIM*300172) mutations are associated with a broad spectrum of phenotypes in both females and males. There are two main types of clinical presentation: microcephaly with pontine and cerebellar hypoplasia (MICPCH), generally associated with pathogenic loss-of-function variants in CASK and X-linked intellectual disability with or without nystagmus, generally associated with hypomorphic CASK pathogenic variants. The X-linked CASK gene mutations leading to MICPCH are predominantly identified in female patients and it has been hypothesized that CASK loss-of-function mutations are associated with reduced male viability or in utero lethality. So far only a few male patients with CASK mutations exhibiting a severe phenotype with perinatal lethality or death within the first months of life have been reported. We delineate the clinical course of a male infant with a novel mutation of the CASK gene, prolonged survival and lissencephaly.