NAT-9 is a 207 amino acid protein belonging to the acetyltransferase family and the GNAT subfamily. Containing a N-acetyltransferase domain, NAT-9 may be associated with psoriasis and psoriatic arthritis, a type of inflammatory/autoimmune disease that affects skin, tendons and/or joints of the hands and feet. Expressed as two isoforms produced by alternative splicing events, NAT-9 is encoded by a gene located on human chromosome 17, which comprises over 2.5% of the human genome and encodes over 1,200 genes.