Chiari in the family: inheritance of the Chiari I malformation.

This report presents three families with Chiari malformation type I that became symptomatic during childhood: a mother and son; a set of monozygotic twins; and two half-siblings and their two maternal cousins. These children presented with various symptoms, including headache, stiff neck, and swallowing difficulty. A review of the relevant literature is presented, with an emphasis on familial examples and proposed inheritance. Less common presentations of Chiari malformation type I are discussed, as well as the possible pathogenesis of Chiari malformation type I and associated syringomyelia.