Transmembrane emp24 domain-containing protein 5 is a protein that in humans is encoded by the TMED5 gene. TMED5 is a 229 amino acid single-pass type I membrane protein that belongs to the EMP24/GP25L family and contains one GOLD domain. The gene that encodes TMED5 contains nearly 31,000 bases and maps to human chromosome 1p22.1. As the largest human chromosome, chromosome 1 spans about 260 million base pairs and makes up approximately 8% of the human genome. There are about 3,000 genes on chromosome 1, and considering the great number of genes there are also a large number of diseases associated with chromosome 1. Notably, the rare aging disease Hutchinson-Gilford progeria is associated with the LMNA gene which encodes lamin A. When defective, the LMNA gene product can build up in the nucleus and cause characteristic nuclear blebs. The MUTYH gene is located on chromosome 1 and is partially responsible for familial adenomatous polyposis. Stickler syndrome, Parkinsons, Gaucher disease and Usher syndrome are also associated with chromosome 1.