GPR63 is a G-protein-coupled receptor that may be important for forebrain development during embryogenesis, and mutations are correlated with microcephaly. It seems to play a role in normal brain function in adults. In immunohistochemistry, GPR63 has membranous positivity in the brain, specifically on Purkinje neurons of the cerebellum, neurons of the substantia nigra, and also on some microglia and astrocytes. It also has low to moderate staining in various peripheral tissues, including the colon, small intestine, heart, skeletal muscle, kidney, lung, and placenta. References: Biorxiv. 2018. Preprint. DOI: 10.1101/424341v1;