in the gray-white junction, along with markedly increased cortical thickness, distinguishes lissencephaly. GPR56 mutation also can cause a severe encephalopathy which is associated with electro clinical features of the Lennox-Gastaut syndrome. Lennox-Gastaut syndrome can be cryptogenic or symptomatic, but the symptomatic forms have been associated with multiple etiologies and abnormal cortical development. BFPP caused by GPR56 mutations is a manifestation of a malformation of cortical development that causes Lennox-Gastaut Syndrome. Polymicrogyria is often confused with pachygyria; therefore, it needs to be distinguished from pachygyria, a distinct brain malformation in which the surface folds are excessively broad and sparse. Pachygyria and polymicrogyria may look similar on low-resolution neuroimaging such as CT because the cortical thickness can appear to be increased and the gyri can appear to be broad and smooth in both conditions. This is why higher resolution neuroimaging, such as an MRI, is necessary for proper diagnosis. Genetics The GPR56 is grouped in the B family of GPCRs. This GPCR group have long N termini characterized by an extracellular “cysteine box” and hydrophilic, potentially mucin-rich. The cysteine box contains four conserved cysteines and two tryptophans arranged in a specific fashion (C-x2-W-x6-16-W-x4-C-x10-22-C-x-C) just before the first transmembrane domain and serves as a cleavage site in some members of this group of G protein–coupled receptors. Although, the molecular and cellular mechanisms of how GPR56 regulates brain development remain largely unknown. These types of receptors play an essential role in biological processes including embryonic development, central nervous system (CNS), immune system, and tumorigenesis. Mode of inheritance Parents of a proband The parents of an affected individual are obligate heterozygotes and therefore carry one mutant allele. Heterozygotes (carriers) are asymptomatic. Sibs of a proband At conception, each sibling of an affected individual has a 25% chance of being affected, a 50% chance of being an asymptomatic carrier, and a 25% chance of being unaffected and not a carrier. Once an at-risk sibling is known to be unaffected, the risk of his/her being a carrier is 2/3. Heterozygotes (carriers) are asymptomatic. Offspring of a proband Offspring of a proband are obligate heterozygotes and will therefore carry one mutant allele. In populations with a high rate of consanguinity, the offspring of a person with GPR56-related BFPP and a reproductive partner who is a carrier of GPR56-related BFPP have a 50% chance of inheriting two GPR56 disease-causing alleles and having BFPP and a 50% chance of being