Monarch Disease Ontology term MONDO_0012212 (Loeys-Dietz syndrome 1) is a rare autosomal dominant syndrome caused by mutations in the TGFBR1 gene. It is characterized by vascular abnormalities (aortic and arterial aneurysms, aortic dissection, and tortuosity of the arteries), hypertelorism, bifid uvula, and early fusion of the skull bones. Also known as: Furlong syndrome, Loeys-Dietz syndrome caused by mutation in TGFBR1, Loeys-Dietz syndrome type 1, TGFBR1 Loeys-Dietz syndrome.