A Novel Splice Site Mutation in the RASA1 Gene Causing Rare Diffuse Gastrointestinal Vascular Malformations: A Case Report and Literature Review.
Lang Wu, Shoubin Ning, Hongyu Chen et al.
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Case in brief
A 29-year-old man with intermittent hematochezia had diffuse vascular malformations involving the stomach and small bowel on contrast-enhanced CT, double-balloon enteroscopy, and superior mesenteric angiography. Genetic testing identified a heterozygous de novo RASA1 splice-donor variant, predicted to be pathogenic, consistent with CM-AVM. The lesions were too extensive for curative resection. He was discharged for close surveillance, with a plan to trial sirolimus and use selective surgical, interventional, or endoscopic hemostasis if needed.
What made this case unusual
The report describes diffuse gastrointestinal vascular malformations associated with a RASA1 variant, extending the reported phenotype beyond the typical CM-AVM presentation.
Diagnostic / clinical pearl
In a young patient with obscure gastrointestinal bleeding and multifocal vascular lesions, consider germline RASA1 testing, particularly when imaging suggests diffuse involvement.
Why it matters
Molecular diagnosis can support family counseling and targeted surveillance, as well as inform individualized management when lesions are too extensive for curative resection.