This gene encodes a member of a family of multipass membrane proteins that functions as calcium channels. The encoded protein contains N-terminal ankyrin repeats, which are required for channel assembly and regulation. Translation initiation for this protein occurs at a non-AUG start codon that is decoded as methionine. This gene is situated next to a closely related gene for transient receptor potential cation channel subfamily V member 5 (TRPV5). This locus has experienced positive selection in non-African populations, resulting in several non-synonymous codon differences among individuals of different genetic backgrounds. [provided by RefSeq, Feb 2015].