A Novel Splice Site Mutation in HPS1 Gene is Associated with Hermansky-Pudlak Syndrome-1 (HPS1) in an Iranian Family

&: The first two authors contributed equally. ∗Corresponding author: Genomic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Email: [email protected] ermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder which is characterized by oculocutaneous albinism, bleeding, and lysosomal ceroid storage resulted from deficiencies in multiple cytoplasmic organelles including melanosomes, platelet-dense granules, and lysosomes (1). A wide variation has been detected in the phenotypes of patients suffering from this disorder. The amount of pigmentation of the skin, hair, iris and fundus is markedly different among patients with HPS from an almost total absence of pigment to a nearly normal amount. Pigmentation degree possibly increases with age (2). Although the bleeding tendency is mild in these patients, certain evaluations are necessary before any surgery to prevent life-threatening complications (2). Ceroid deposition in these patients would result in pulmonary fibrosis and granulomatous colitis (3) with the former being the main cause of death in HPS after 1 year of age (4). No generalized defect has been detected in peripheral blood lymphocyte or neutrophil function in a group of studied HPS patients (5). However an association has been observed between HPS and lupus or frequent bacterial infections which is attributed to a defect within the monocyte-macrophage system, possibly secondary to ceroid accumulation and decreased activity of natural killer cells, respectively (6). Several genetic loci have been shown to be associated with different types of HPS. Among them is the HPS1 gene associated with HPS1 (OMIM #203300) which encodes a transmembrane protein that is believed to be a component of multiple cytoplasmic organelles and is critical for their normal development and function (1). Accordingly, it is a part of a protein complex that controls the intracellular localization of lysosomes and late endosomes and participates in the biogenesis of lysosome-related organelles complex as well as melanosome biogenesis (7). Here we report a 22-year-old patient presented with generalized skin hypopigmentation, brown hair, reduced visual acuity, photophobia, and nystagmus. He reported a history of easily bruising with minor trauma, without any history of internal organ bleeding. His parents were consanguineous (Figure 1). No symptom or sign of pulmonary H Submmited 9 May 2016; Accepted 11 June 2016; Published 3 July 2016