The protein encoded by this gene is a highly conserved, calcium-binding protein, that is preferentially expressed in the liver and kidney. It may have an important role in calcium homeostasis. Studies in rat indicate that this protein may also play a role in aging, as it shows age-associated down-regulation. This gene is part of a gene cluster on chromosome Xp11.3-Xp11.23. Alternative splicing results in two transcript variants having different 5 UTRs, but encoding the same protein.