Patients with mutations in ENG (HHT-1), ACVRL1 (HHT-2), and SMAD4 (in association with juvenile polyposis syndrome) underwent endoscopic evaluation, and it was discovered that patients with ENG mutation (HHT-1) had a higher rate of multiple telangiectasias with a higher prevalence of telangiectasias in the duodenum [15]. The gene discussed is ACVRL1; the disease is telangiectasis.