This gene encodes a member of the keratin gene family. This gene is one of multiple type I hair keratin genes that are clustered in a region of chromosome 17q12-q21 and have the same direction of transcription. As a type I hair keratin, the encoded protein is an acidic protein which heterodimerizes with type II keratins to form hair and nails. There are two isoforms of this protein, encoded by two separate genes, keratin 33A and keratin 33B. [provided by RefSeq, May 2012],