Cardoso C - Boys A - Parrini E - Mignon-Ravix C - McMahon JM - Khantane S - Bertini E - Pallesi E - Missirian C - Zuffardi O - Novara F - Villard L - Giglio S - Chabrol B - Slater HR - Moncla A - Scheffer IE - Guerrini R
Periventricular heterotopia (PH) is an etiologically heterogeneous disorder characterized by nodules of neurons ectopically placed along the lateral ventricles. Most affected patients have seizures and their cognitive level varies from normal to severely impaired. At present, two genes have been identified to cause PH when mutated. Mutations in FLNA (Xq28) and ARFGEF2 (20q13) are responsible for X-linked bilateral PH and a rare autosomal recessive form of PH with microcephaly. Chromosomal rearrangements involving the 1p36, 5p15, and 7q11 regions have also been reported in association with PH but the genes implicated remain unknown. Fourteen additional distinct anatomoclinical PH syndromes have been described, but no genetic insights into their causes have been gleaned.