HEXDC, also known as hexosaminidase D, beta-hexosaminidase D, N-acetyl-beta-galactosaminidase, hexosaminidase domain-containing protein or beta-N-acetylhexosaminidase, is a 486 amino acid cytoplasmic and nuclear protein that has hexosaminidase activity and belongs to the glycosyl hydrolase 20 family. Existing as two alternatively spliced isoforms, HEXDC catalyzes the hydrolysis of non-reducing N-acetyl-D-hexosamine residues near the termini of N-acetyl-beta-D-hexosaminides. The gene encoding HEXDC maps to human chromosome 17, which comprises over 2.5% of the human genome and encodes over 1,200 genes. Two key tumor suppressor genes are associated with chromosome 17, namely, p53 and BRCA1. Defects in p53 is associated with malignant cell growth and Li-Fraumeni syndrome. BRCA1 is directly involved in DNA repair and is recognized as a genetic determinant of early onset breast cancer and predisposition to cancers of the ovary, colon, prostate gland and fallopian tubes.