Among 3 variants identified in different genes (OSGIN1, KIF4A, BCAT1) potentially disease-causing according to prediction algorithms we considered the X-linked novel hemizygous missense variant in the KIF4A gene (c.[2096T>A], p.(V699E)) likely to be associated with the isolated hydrocephalus in the male fetus of family 8. The gene discussed is KIF4A; the disease is Hydrocephalus.