We demonstrate that LRMDA coupling to Commander is essential for the RAB32-dependent biogenesis of melanosomes and show that LRMDA mutations, causative for oculocutaneous albinism type 7 (OCA7), a hypopigmentation disorder accompanied by poor visual acuity18, uncouple RAB32 and Commander binding thus establishing the mechanistic basis of this disease. This evidence concerns the gene LRMDA and oculocutaneous albinism type 7.