Case report: Inflammatory bowel disease in Hermansky-Pudlak Syndrome type 3 due to novel variant in HPS3

Jing Qun Mai ^1,2 Zhu Zhang ^1,2* Bo Cheng Mai ^1,2* Shanling Liu ^1,2 He Wang ^1,2* Hao Wang ^1,2* Shuo Yang ^1,2

• ¹ West China Second University Hospital, Sichuan University, Chengdu, China
• ² Key Laboratory of Birth Defects and Related Diseases of Women and Children, West China Second University Hospital, Sichuan University, Chengdu, Sichuan Province, China

Hermansky-Pudlak syndrome (HPS) is a rare autosomal recessive disorder with phenotypic and genetic heterogeneity, characterized by oculocutaneous albinism, bleeding diathesis, and other specific subtypes such as colitis. HPS-3HPS3 is caused by biallelic mutations in HPS3. Patients with HPS-3HPS3 have milder symptoms and were rarely reported to be involved in digestive disorders. P A G E 2 19 novel homozygous nonsense variant (NM_032383.5; c.2887G>T, p.E963*) was identified in HPS3, which introduced premature termination codons and generated aberrant splicing-mediated mRNA decay, resulting in loss of function of the gene.Trio-based whole-exome sequencing (Trio-WES) identified a novel homozygous nonsense variant (NM_032383.5; c.2887G>T, p.E963*) in HPS3, resulting leading toin premature termination codons, and aberrant splicing-mediated mRNA decay, and loss of gene function. The patient received medical treatment including corticosteroids and mercaptopurine to help relieve IBD symptoms and took regular follow-ups. He is now in clinical remission but with a tendency to recur.The patient was treated with corticosteroids and mercaptopurine for management of IBD symptoms and has been attending ed follow-up appointmentss. Currently, Hethe patient is in clinical remission ;however, there remains a potential risk of but may relapse.We presentreport a rare case of HPS-related IBD caused byresulting from a homozygous variant in HPS3 and provide insights into the understanding of the diagnosis and treatment of HPS-3HPS3.