In sum, HPS2 is the result of the absence of the entire AP-3 complex, which results in severe neutropenia with a defect in granule formation as the major hematological finding.
We now report 2 unrelated subjects with HPS2 who show a characteristic clinical phenotype of oculocutaneous albinism, platelet and T-lymphocyte dysfunction and neutropenia.
In combination with neutropenia, this suggested the diagnosis of Hermansky-Pudlak syndrome type II (HPSII) and a novel homozygous mutation in AP3B1 was detected.
Our findings expand the molecular, cellular, and clinical spectrum of HPS-2 and call for an increased index of suspicion for this diagnosis among patients with features of albinism, bleeding, and neutropenia.