Heřmanský–Pudlák syndrome (often written Hermansky–Pudlak syndrome or abbreviated HPS) is an extremely rare autosomal recessive disorder which results in oculocutaneous albinism (decreased pigmentation), bleeding problems due to a platelet abnormality (platelet storage pool defect), and storage of an abnormal fat-protein compound (lysosomal accumulation of ceroid lipofuscin). It is considered to affect around 1 in 500,000 people worldwide, with a significantly higher occurrence in Puerto Ricans, with a prevalence of 1 in 1800. Many of the clinical research studies on the disease have been conducted in Puerto Rico. There are eight classic forms of the disorder, based on the genetic mutation from which the disorder stems. Signs and symptoms There are three main disorders caused by Hermansky–Pudlak syndrome, which result in these symptoms: Albinism and eye problems: Individuals will have varying amounts of skin pigment (melanin). Because of the albinism there are eye problems such as light sensitivity (photophobia), strabismus (crossed eyes), and nystagmus (involuntary eye movements). Hermansky–Pudlak syndrome also impairs vision. Bleeding disorders: Individuals with the syndrome have platelet dysfunction. Since platelets are necessary for blood clotting, individuals will bruise and bleed easily. Cellular storage disorders: The syndrome causes a wax-like substance (ceroid) to accumulate in the body tissues and cause damage, especially in the lungs and kidneys. It is also associated with granulomatous colitis,, an inflammation of the colon, and with pulmonary fibrosis, a potentially fatal lung disease. Causes HPS can be caused by mutations in several genes: HPS1, HPS3, HPS4, HPS5, HPS6 and HPS7. HPS type 2, which includes immunodeficiency in its phenotype, is caused by mutation in the AP3B1 gene. HPS type 7 may result from a mutation in the gene coding for dysbindin protein. Hermansky–Pudlak syndrome is thought to be inherited as an autosomal recessive genetic trait. The defective gene, called HSP , responsible for this disorder is located on the long arm of chromosome 10 (10q2). Some research suggests that an abnormality of lysosomal function may be responsible for the development of the disease. HPS1, AP3B1, HPS3, HPS4, HPS5, HPS6, DTNBP1 and Biogenesis of Lysosome-related Organelles Complex (BLOC1, BLOC1S2 and BLOC3) are associated with Hermansky–Pudlak syndrome. In autosomal recessive disorders, the condition does not appear unless a person inherits two copies of the defective gene responsible for the disorder, one copy coming from each parent. If an individual receives one normal gene and one gene for the disorder, the person will be a carrier for