Hermansky-Pudlak syndrome consists of a group of genetically heterogeneous disorders resulting from homozygous mutations in at least 9 genes. The major features include oculocutaneous albinism, immunodeficiency, abnormal bleeding, and lysosomal ceroid storage. Bleeding abnormalities include prolonged bleeding time and defective platelet aggregation. Platelets lack the usual dense bodies. Hypopigmentation is notable in the skin, eyes, and hair, but excess pigmentation is seen in reticuloendothelial cells.

The disorder may be the most common single gene disorder in Puerto Rico, where the carrier frequency has been estimated to be as high as 1 in 21 individuals.