Bilateral frontoparietal polymicrogyria (BFPP) [OMIM #606854] is characterized by moderate-severe mental retardation, seizures, dysconjugate gaze, and characteristic radiological findings. Mutations of the GPR56 [OMIM #604110] gene, or G-protein coupled receptor 56, have been identified in patients with BFPP. Piao X, et al  studied patients with BFPP along with some patients with other polymicrogyria syndromes. All 29 patients with BFPP were found to be homozygous for GPR56 mutations. However, no patients without the BFPP cortical distribution or without both white matter and posterior fossa changes were found to mutations in GPR56. Deletions and/or duplications of the GPR56 gene as causative of disease have been reported.
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