Oculocutaneous albinism and bleeding diathesis due to a novel deletion in the HPS3 gene

Hermansky-Pudlak syndrome (HPS) is a group of rare autosomal recessive disorders characterized by oculocutaneous albinism (OCA) and bleeding diathesis. To date, 11 HPS types have been reported (HPS-1 to HPS-11), each defined by disease-causing variants in specific genes. Variants in the HPS1 gene were found in approximately 15% of HPS patients, most of whom harbor the Puerto Rican founder mutation. In this study, we report six affected individuals from three nonconsanguineous families of Ashkenazi Jewish descent, who presented with OCA and multiple ecchymoses and had normal platelet number and size. Linkage analysis indicated complete segregation to HPS3. Sequencing of the whole coding region and the intron boundaries of HPS3 revealed a heterozygous c.1163+1G>A variant in all six patients. Long-range PCR amplification revealed that all affected individuals also carry a 14,761bp deletion that includes the 5'UTR and exon 1 of HPS3, encompassing regions with long interspersed nuclear elements. The frequency of the c.1163+1G>A splice site variant was found to be 1:200 in the Ashkenazi Jewish population, whereas the large deletion was not detected in 300 Ashkenazi Jewish controls. These results present a novel HPS3 deletion mutation and suggest that the prevalence of HPS-3 in Ashkenazi Jews is more common than previously thought.