juvenile polyposis/hereditary hemorrhagic telangiectasia syndrome
An autosomal dominant syndrome caused by pathogenic variants in the SMAD4 gene, characterized by the combined features of juvenile polyposis syndrome (JPS) and hereditary hemorrhagic telangiectasia (HHT). JPS features include multiple juvenile polyps in the gastrointestinal tract and an increased risk of gastrointestinal cancers. HHT features include arteriovenous malformations (AVMs) and telangiectasias.