Acute intestinal ischemia secondary to splanchnic venous thrombosis caused by a novel pathogenic PROS1 mutation: a case report

Hereditary protein S deficiency is a rare thrombotic disease caused by pathogenic variants in the PROS1 gene, predisposing individuals to an increased risk of venous thromboembolism. A 41-year-old male patient with a history of cerebral venous sinus thrombosis presented to the emergency department with acute abdominal pain and hematochezia. Contrast-enhanced computed tomography showed portal, splenic, and superior mesenteric venous thrombosis. Complicated by acute intestinal ischemia, the patient underwent emergency bowel resection. Laboratory assays demonstrated markedly reduced protein S activity. Next-generation sequencing identified a heterozygous deletion in the PROS1 gene, resulting in a frameshift mutation and the creation of a premature termination codon. To date, this variant has not been previously reported, representing a novel pathogenic mutation of the PROS1 gene. This case highlights the critical importance of investigating hereditary thrombophilia in young patients presenting with acute abdominal pain and unprovoked thrombosis at atypical sites, facilitating timely diagnosis and appropriate long-term management.