In Chromosome 15, the 21,701 bases long gene starts from 48,120,972 bp from pter and ends at 48,142,672 bp from pter; Orientation: Plus strand. It contains 9 exons.

This gene has 5 transcripts: 4 splice variants and 1 unspliced form (http://www.ncbi.nlm.nih.gov/IEB/Research/Acembly/av.cgi?db=human&c=Gene&l=SLC24A5). The full protein coding transcript is 1617 bp long.

The gene encodes a cation exchanger which is 500 amino acids protein of molecular mass 54888 Da; this multi-pass membrane protein is an intracellular potassium-dependent sodium/calcium exchanger with 2 large hydrophilic loops and 2 sets of multiple trans-membrane-spanning segments. The first large hydrophilic loop is located extracellularly at the N-terminus while the other is cytoplasmic and separates the two sets of transmembrane domains. It belongs to sodium/potassium/calcium exchanger family, SLC24A subfamily.

Due to its localization in the melanosomal membrane, SLC24A5 is thought to be expressed in the melanocytes (Wilson S et al., 2013). Interestingly, the expression of the gene in the following tissue types are evident by its existence in the corresponding cDNA libraries: B-cell, brain, cerebellum, cerebrum, colon, embryonic tissue, fetus, gastrointestinal tract, kidney, liver, lung, lymph node, lymphoreticular, mammary gland, nervous, pancreas, pancreatic islet, placenta, prostate, skin, stem cell, stomach, testis, thymus, uterus and vascular tissue (http://cgap.nci.nih.gov/Genes/GeneInfo?ORG=Hs&CID=710240).

SLC24A5 is expressed in the trans-Golgi network of melanocytes (Wilson S et al., 2013).

The precise function of SLC24A5 is not yet known. However, the potential functions include: (a) transporting 1 Ca²⁺ and 1 K⁺ to the melanosome in exchange for 4 cytoplasmic Na (Lamason RL et al., 2005); (b) Influencing natural variation in skin pigmentation via an unknown mechanism affecting cellular sterol levels (Wilson S et al., 2013).

It belongs to Solute Carrier Family 24 (http://www.guidetopharmacology.org/GRAC/FamilyDisplayForward?familyId=202).

SLC24A5 mutations are responsible for Oculocutaneous Albinism type 6 (OCA6). Only 9 SLC24A5 mutations have been reported till date - one patient from India, one from China, two from France, three from Portugal, one from Belgium and one from Syria (Mondal et al. 2012; Wei et al., 2013; Fanny et al., 2014). Patients are generally characterized by light hair at birth that darkens with age, white skin, transparent irises, photophobia, nystagmus, foveal hypoplasia and reduced visual acuity. In a man from eastern India who had extreme hypopigmentation resulting in pinkish-white skin, but with dark brown hair and brown irises, was found to have a 4-bp insertion in the SLC24A5 gene as homozygous genotype (Mondal et al, 2012).

Somatic variations in SLC24A5 have been identified in cancers (https://dcc.icgc.org/mutations/MU45848787; http://cancer.sanger.ac.uk/cosmic/search?q=SLC24A5), but no causality have been reported.