Ichthyosis-hepatosplenomegaly-cerebellar degeneration syndrome is characterised by ichthyosis, hepatosplenomegaly and late-onset cerebellar ataxia. It has been described in two brothers. Transmission is either autosomal recessive or X-linked.

A loss of global cognitive ability of sufficient amount to interfere with normal social or occupational function. Dementia represents a loss of previously present cognitive abilities, generally in adults, and can affect memory, thinking, language, judgment, and behavior.