In addition to these two genes, there are more than ten known causative OCA genes (TYRP1, SLC45A2, SLC24A5, LRMDA, MITF, HPS1, AP3B1, HPS3, HPS4, BLOC1S3, HPS5, HPS6, DTNBP1, BLOC1S6, AP3D, BLOC1S5, GPR143, LYST, MY5A, RAB27A, and MLPH) (Federico and Krishnamurthy, 2021), although their related OCA is relatively rare. This evidence concerns the gene HPS4 and oculocutaneous albinism.