GPR143 and X-linked recessive ocular albinism: Expression of OA1-232c (T232K), which contains a single missense mutation found in ocular albinism type 1 patients, and OA1-Δ18, which has a deletion of 18 amino acids within the i3 cytosolic loop region of OA1 responsible for its GPCR activity (Innamorati et al., 2006; Palmisano et al., 2008) did not cause a significant increase in MVBs, suggesting that the increased MVB number caused by overexpression of OA1-wt is dependent on OA1 activity.