Surprisingly good outcome in antenatal diagnosis of severe hydrocephalus related to CCDC88C deficiency.

Non-syndromic congenital hydrocephalus is aetiologically diverse and while a genetic cause is frequently suspected, it often cannot be confirmed. The most common genetic cause is L1CAM-related X-linked hydrocephalus and that explains only 5%-10% of all male cases. This underlines a current limitation in our understanding of the genetic burden of non-syndromic congenital hydrocephalus, especially for those cases with likely autosomal recessive inheritance. Additionally, the prognosis for most cases of severe congenital hydrocephalus is poor, with most of the surviving infants displaying significant intellectual impairment despite surgical intervention. It is for this reason that couples with an antenatal diagnosis of severe hydrocephalus are given the option, and may opt, for termination of the pregnancy. We present two families with CCDC88C-related recessive congenital hydrocephalus with children who had severe hydrocephalus. Those individuals who were shunted within the first few weeks of life, who did not require multiple surgical revisions, and who had a more distal truncating variant of the CCDC88C gene met their early childhood developmental milestones in some cases. This suggests that children with CCDC88C-related autosomal recessive hydrocephalus can have normal developmental outcomes under certain circumstances. We recommend CCDC88C analysis in cases of severe non-syndromic congenital hydrocephalus, especially when aqueduct stenosis with or without a medial diverticulum is seen, in order to aid prognosis discussion.