including gpr56 gene. to date the only gene known to be associated with polymicrogyria is gpr56. testing for gpr56-related bilateral frontoparietal polymicrogyria is available clinically. mutations in gpr56 hinders collagen iii, its specific ligand, to bind in a developing brain. to date, a total of fourteen bfpp-associated mutations have been identified, including one deletion, two splicing, and eleven missense mutations. two mutations in the gpcr proteolytic site (gps) domain, c346s and w349s, cause a brain malformation through trapping the mutated proteins in the endoplasmic reticulum.