Given that the physical interaction among these three factors to form a protein complex is required for melanosome transport [32]–[34], [38] and that the three subtypes of GS share a trait of hypopigmentation, it is reasonable to consider that the MYO5A-SLAC2-A-RAB27A complex plays a pivotal role in melanosome transport and in consequent cutaneous pigmentation in humans. The gene discussed is MYO5A; the disease is Gerstmann syndrome.