Najm type X-linked intellectual deficit is a rare cerebellar dysgenesis syndrome characterized by variable clinical manifestations ranging from mild intellectual deficit with or without congenital nystagmus, to severe cognitive impairment associated with cerebellar and pontine hypoplasia/atrophy and abnormalities of cortical development. The disease is X-linked intellectual disability, Najm type (Orphanet_163937). Also known as: MICPCH, X-linked intellectual disability - microcephaly - pontocerebellar hypoplasia.