The ACVRL1 gene provides instructions for making a specific kind of protein that is found in the lining of developing blood vessels.  This protein interacts with growth factors that control the development of blood vessels.  Mutations in this gene produce a deficient or defective protein which cannot perform its function in the tissue lining the blood vessels.

Mutations in the ACVRL1 gene cause Hemorrhagic Telangiectasia Type 2, a condition characterized by the presence of blood vessel abnormalities.  

The ACVRL1 gene is located on the long arm of chromosome 12, where it spans a length of over 16 Kb.  The gene consists of ten exons, nine of which are coding.  The ALK1 protein is a serine-threonine kinase that acts as a type I cell-surface receptor for the TGF-beta superfamily of ligands.  The protein is constituted of 503 amino acid residues and has a molecular size of close to 56 kDa.  It consists of a transmembrane domain, as well as a GS domain rich in glycine and serine along with the protein kinase domain. 

Several mutations in this gene leading to HHT2 have been described in the literature.  Most of these are missense mutations.  A particular variant (IVS3-35 A>G) has also been shown to be associated with the development arteriovenous malformations in the brain.