Monosomy 5p, also known as Cri du chat syndrome, is a rare autosomal deletion syndrome characterized by a mewing cry (cri du chat) in infancy, multiple congenital anomalies, intellectual disability, microcephaly, and facial dysmorphism.

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.