BAI2 is an Orphan-B GPCR with an unknown ligand. Decreased BAI2 expression is correlated with the formation of new blood vessels in a murine ischemic model. Along with BAI2, there are two other brain-specific angiogenesis inhibitor genes, designated BAI1 and BAI3, which have similar tissue specificities and structures. Alternative splice forms of BAI2 are differentially regulated during development. BAI2 expression has been reported primarily in the brain, but is also identified in heart, skeletal muscle, thymus, ovary, and testis. ESTs have been isolated from B-cell/lung/testis, bone, brain, fetus, heart, melanocyte/uterus/fetal heart, nerve, pineal, and placenta libraries.