OCA2 gene is located on the long arm (q) of chromosome 15, specifically from base pair 28,000,020 to base pair 28,344,457 on chromosome 15. OCA2 gene is officially called oculocutaneous albinism II. The gene used to be referred to as the P gene. It provides instructions for making the protein called P protein which is located in melanocytes which are specialized cells that produce melanin. Melanin is responsible for giving color to the skin, hair, and eyes. Moreover, melanin is found in the light-sensitive tissue of the retina of the eye which plays a role in normal vision. The exact function of protein P is unknown, but it has been found that it is essential for the normal coloring of skin, eyes, and hair; and likely involved in melanin production. This gene seems to be the main determinant of eye color depending on the amount of melanin production in the stroma of the iris (large amounts giving rise to brown eyes; little to no melanin giving rise to blue eyes). Mutations in the OCA2 gene cause a disruption in the normal production of melanin; therefore, causing vision problems and reductions in hair, skin, and eye color. Oculocutaneous albinism is a health condition caused by mutations in the OCA2 gene. Other diseases associated with the deletion of OCA2 gene are Angelman syndrome (light-colored hair and fair skin) and Prader-Willi syndrome (unusually light-colored hair and fair skin). With both these syndromes, the deletion often occurs in individuals with either syndrome.
| Oculocutaneous albinism II | |||||||||||||
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| Identifiers | |||||||||||||
| Symbols | OCA2; BEY; BEY1; BEY2; BOCA; D15S12; EYCL; EYCL2; EYCL3; HCL3; P; PED; SHEP1 | ||||||||||||
| External IDs | OMIM: 611409 MGI: 97454 HomoloGene: 37281 GeneCards: OCA2 Gene | ||||||||||||
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| RNA expression pattern | |||||||||||||
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| Orthologs | |||||||||||||
| Species | Human | Mouse | |||||||||||
| Entrez | 4948 | 18431 | |||||||||||
| Ensembl | ENSG00000104044 | ENSMUSG00000030450 | |||||||||||
| UniProt | Q04671 | Q62052 | |||||||||||
| RefSeq (mRNA) | NM_000275 | NM_021879 | |||||||||||
| RefSeq (protein) | NP_000266 | NP_068679 | |||||||||||
| Location (UCSC) | Chr 15: 28 – 28.34 Mb |
Chr 7: 56.24 – 56.54 Mb |
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| PubMed search | |||||||||||||
P protein is a protein that, in humans, is encoded by the OCA2 gene. OCA2 encodes the human homologue of the mouse p (pink-eyed dilution) gene. The P protein is believed to be an integral membrane protein involved in small molecule transport, specifically tyrosine - a precursor of melanin. Certain mutations in OCA2 result in type 2 oculocutaneous albinism.
A mutation in the HERC2 gene adjacent to OCA2, affecting OCA2's expression in the human iris, is found common to nearly all people with blue eyes. It has been hypothesized that all blue-eyed humans share a single common ancestor with whom the mutation originated.
A 2010 study found the His615Arg allele of OCA2 is involved in the light skin tone in people of East Asian descent.