A 140 kb homozygous deletion from 22q12 in one meningioma directed us towards the cloning and characterization of a new member of the human beta-adaptin gene family (named BAM22). Adaptins are essential for the formation of clathrin coated vesicles in the course of intracellular transport of receptor-ligand complexes. The BAM22 gene is totally inactivated in the tumor with homozygous deletion. Northern blot analysis of 70 sporadic meningiomas showed specific loss of expression in 8 tumors, suggesting inactivation of BAM22. Based on this, we propose BAM22 as a second chromosome 22 locus important in meningioma development, after the neurofibromatosis type 2 gene.