{Reference Type}: Case Reports
{Title}: Unraveling Hermansky-Pudlak syndrome type 7: a case report and comprehensive literature review on the identification of DTNBP1 variants.
{Author}: Rodrigues R;Quental R;Santos Silva R;Costa L;Estrela-Silva S;
{Journal}: Ophthalmic Genet
{Volume}: 45
{Issue}: 3
{Year}: 2024 Jun 14
{Factor}: 1.274
{DOI}: 10.1080/13816810.2023.2291670
{Abstract}: <B>UNASSIGNED: </B>We report a case of Hermansky-Pudlak Syndrome type 7 (HPS-7) caused by a homozygous variant in the dystrobrevin-binding protein 1 gene (DTNBP1) and highlight the genetic challenges associated with this rare disorder.<BR><B>UNASSIGNED: </B>Case report. Literature review was performed by searching PubMed on May 2023, without language or date restriction, using the following terms: Hermansky-Pudlak syndrome, Hermansky-Pudlak syndrome type 7, and dystrobrevin-binding protein 1 gene.<BR><B>UNASSIGNED: </B>We report a case of a 69-year-old Portuguese female who presented for ophthalmic evaluation with long-standing severe visual impairment, pronounced photophobia, right-eye esotropia, and bilateral pendular nystagmus. Anterior segment examination revealed iris transillumination defects, while the ocular fundus showed hypopigmentation and the absence of the foveal reflex. The patient had a history of oculocutaneous albinism (OCA) and recurrent epistaxis. Her family history was positive for first-degree consanguineous parents and a deceased sister at young age who also exhibited OCA and recurrent epistaxis. Genetic testing identified a homozygous pathogenic nonsense variant in the DTNBP1, c.307C>T p.(Gln103*). The patient's clinical features and genetic testing support the diagnosis of HPS-7. The identified variant has been previously reported in the literature, in adult patients of Portuguese descent.<BR><B>UNASSIGNED: </B>This work highlights the genetic complexity of HPS-7 and emphasizes the importance of genetic testing in the diagnosis of this rare disorder. The identification of a rare pathogenic variant expands our understanding of HPS-7 genetics and suggests a possible founder effect in the Portuguese population.