 Lastly, variable region 3 (vr3) consists of exons 11A, 11B, and 12, and exon 11B encodes the unique C-terminal tail of α-dystrobrevin 3.In mouse skeletal muscle, the splicing of vr2 and vr3 has been reported to be developmentally controlled.The human β-dystrobrevin gene was localized to the short arm of chromosome 2.