MedGen

Congenital hydrocephalus-1 (HYC1) is characterized by onset in utero of enlarged ventricles due to a disturbance of cerebrospinal fluid accumulation. Affected individuals may have neurologic impairment (summary by Drielsma et al., 2012). Hydrocephalus can also be caused by Arnold-Chiari malformation, atresia of foramen of Magendie, stenosis of aqueduct of Sylvius (307000), toxoplasmosis, hydranencephaly, etc. Furthermore, it develops in infancy or childhood in achondroplasia (100800) and in Hurler disease (607014). Genetic Heterogeneity of Congenital Hydrocephalus See also HYC2 (615219), caused by mutation in the MPDZ gene (603785) on chromosome 9p23; HYC3 (617967), caused by mutation in the WDR81 gene (614218) on chromosome 17p13; HYC4 (618667), caused by mutation in the TRIM71 gene (618570) on chromosome 3p22; and HYC5 (620241), caused by mutation in the SMARCC1 gene (601732) on chromosome 3p23. An X-linked form of congenital hydrocephalus (HSAS, HYCX; 307000) is caused by mutation in the L1CAM gene on (308840) on chromosome Xq28. [from OMIM]

Hydrocephalus is an active distension of the ventricular system of the brain resulting from inadequate passage of CSF from its point of production within the cerebral ventricles to its point of absorption into the systemic circulation. [from HPO]