Hermansky-Pudlak syndrome 2

Defects in ADTB3A are the cause of Hermansky-Pudlak syndrome type 2 (HPS2). HPS is an autosomal recessive disorder characterized by oculocutaneous albinism, bleeding due to platelet storage pool deficiency, and lysosomal storage defects. This syndrome results from defects of diverse cytoplasmic organelles including melanosomes, platelet dense granules and lysosomes. Ceroid storage in the lungs is associated with pulmonary fibrosis, a common cause of premature death in individuals with HPS. HPS2 differs from the other forms of HPS in that it includes immunodeficiency in its phenotype and patients with HPS2 have an increased susceptibility to infections.

Alternative names



  • Defects of phagocyte function


Autosomal recessive


#608233 Hermansky-Pudlak syndrome 2; HPS2

*603401 Adaptor-related protein complex 3, beta-1 subunit; AP3B1

Cross references

Phenotypically related immunodeficiencies

IDR factfile for Chediak-Higashi syndrome

IDR factfile for Griscelli syndrome


Incidence is not known.