Chiari malformation type 1 (CM 1) is defined asherniation ofcerebellar tonsils 4-5 mm below the foramen magnum. Multiple developmental factors like defective development of pontine flexure and shallow posterior fossa are the proposed factors which predispose the development of this syndrome. These reports on familial occurrence of this syndrome correlates with the embryonal- developmental etiology of Chiari 1 malformation. Recent advances in the understanding of the influence of genes and pathogenesis of familial Chiari malformation are expected to improve management of affected patients and monitoring of at-risk family members.