Hint2 (histidine triad nucleotide binding protein 2), also known as HIT-17, is a 163 amino acid secreted protein that contains one HIT domain, a histidine triad that has catalytic activity toward the å-phosphate of ribonucleotides. Via its HIT domain, Hint2 is thought to function as a hydrolase that is encoded by a gene which maps to chromosome 9. Chromosome 9 contains 145 million base pairs and comprises 4% of the human genome, encoding nearly 900 genes. Hereditary hemorrhagic telangiectasia and Familial dysautonomia are both associated with chromosome 9. Notably, chromosome 9 encompasses the largest interferon family gene cluster.