SMAD4 and hereditary hemorrhagic telangiectasia: A patient with definite HHT will have at least 3 of the 4 Curaçao Criteria, or a pathogenic sequence variant in ENG, ACVRL1 or SMAD4. Identification of pulmonary arteriovenous malformations (PAVMs) is recommended for all HHT patients because PAVMs commonly cause preventable complications in asymptomatic patients [18, 19].