DHRSX (dehydrogenase/reductase SDR family member on chromosome X) is a 330 amino acid protein belonging to the short-chain dehydrogenases/reductases (SDR) family. Widely expressed, DHRSX is an oxidoreductase that contains a coenzyme binding site and a substrate binding site, indicating a possible role in cellular metabolism. The gene that encodes DHRSX is located in the pseudoautosomal region 1 (PAR1) of X and Y chromosomes. The X and Y chromosomes are the human sex chromosomes. Chromosome X consists of about 153 million base pairs and nearly 1,000 genes. The combination of a X and Y chromosome lead to normal male development while two copies of X lead to normal female development. There are a number of conditions related to an unusual number and combination of sex chromosomes being inherited, including Turner's syndrome, Klinefelter's syndrome and Triple X syndrome. Color blindness, hemophilia, and Duchenne muscular dystrophy are well known X chromosome-linked conditions which affect males more frequently as males carry a single X chromosome.