Hermansky-Pudlak syndrome 4

Any Hermansky-Pudlak syndrome in which the cause of the disease is a mutation in the HPS4 gene that disrupts biogenesis of lysosome‑related organelles, resulting in melanosome defects and absence of platelet dense bodies. The core phenotype comprises oculocutaneous albinism with reduced visual acuity and nystagmus, and a platelet‑type bleeding tendency. Pulmonary fibrosis and/or granulomatous colitis may occur in this subtype.