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{{Infobox_gene}}
{{PBB_Controls
'''P protein''', also known as '''melanocyte-specific transporter protein''' or '''pink-eyed dilution protein homolog''', is a [[protein]] that in humans is encoded by the '''oculocutaneous albinism II''' ('''OCA2''') [[gene]].<ref name="entrez">{{cite web | title = Entrez Gene: OCA2 oculocutaneous albinism II (pink-eye dilution homolog, mouse)| url = https://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=4948| accessdate = 2015-03-12 }}</ref> 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]].<ref name="entrez"/>  OCA2 encodes the human homologue of the mouse p (pink-eyed dilution) gene.
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<!-- The GNF_Protein_box is automatically maintained by Protein Box Bot.  See Template:PBB_Controls to Stop updates. -->
[[File:OCA2 gene location.png|thumb|In human, the OCA2 gene is located on the long (q) arm of [[Chromosome 15 (human)|chromosome 15]] between positions 12 and 13.1]]
{{GNF_Protein_box
The human 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.
| image = 
| image_source = 
| PDB =
| Name = Oculocutaneous albinism II (pink-eye dilution homolog, mouse)
| HGNCid = 8101
| Symbol = OCA2
| AltSymbols =; BOCA; D15S12; P; PED
| OMIM = 203200
| ECnumber = 
| Homologene = 37281
| MGIid = 97454
| GeneAtlas_image1 = PBB_GE_OCA2_206498_at_tn.png
| Function = {{GNF_GO|id=GO:0005215 |text = transporter activity}} {{GNF_GO|id=GO:0005302 |text = L-tyrosine transmembrane transporter activity}} {{GNF_GO|id=GO:0005395 |text = eye pigment precursor transporter activity}} {{GNF_GO|id=GO:0015105 |text = arsenite transmembrane transporter activity}} {{GNF_GO|id=GO:0015137 |text = citrate transmembrane transporter activity}}
| Component = {{GNF_GO|id=GO:0005737 |text = cytoplasm}} {{GNF_GO|id=GO:0016020 |text = membrane}} {{GNF_GO|id=GO:0016021 |text = integral to membrane}}
| Process = {{GNF_GO|id=GO:0006726 |text = eye pigment biosynthetic process}} {{GNF_GO|id=GO:0006810 |text = transport}} {{GNF_GO|id=GO:0007286 |text = spermatid development}} {{GNF_GO|id=GO:0015746 |text = citrate transport}} {{GNF_GO|id=GO:0048066 |text = pigmentation during development}}
| Orthologs = {{GNF_Ortholog_box
    | Hs_EntrezGene = 4948
    | Hs_Ensembl = ENSG00000104044
    | Hs_RefseqProtein = NP_000266
    | Hs_RefseqmRNA = NM_000275
    | Hs_GenLoc_db = 
    | Hs_GenLoc_chr = 15
    | Hs_GenLoc_start = 25673628
    | Hs_GenLoc_end = 26018061
    | Hs_Uniprot = Q04671
    | Mm_EntrezGene = 18431
    | Mm_Ensembl = ENSMUSG00000030450
    | Mm_RefseqmRNA = NM_021879
    | Mm_RefseqProtein = NP_068679
    | Mm_GenLoc_db = 
    | Mm_GenLoc_chr = 7
    | Mm_GenLoc_start = 56107790
    | Mm_GenLoc_end = 56404536
    | Mm_Uniprot = Q0VBP9
  }}
}}
'''Oculocutaneous albinism II (pink-eye dilution homolog, mouse)''', also known as '''OCA2''', is a human [[gene]].<ref name="entrez">{{cite web | title = Entrez Gene: OCA2 oculocutaneous albinism II (pink-eye dilution homolog, mouse)| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=4948| accessdate = }}</ref>


<!-- The PBB_Summary template is automatically maintained by Protein Box Bot.  See Template:PBB_Controls to Stop updates. -->
== Function ==
{{PBB_Summary
OCA2 provides instructions for making the protein called P protein which is located in [[melanocyte]]s 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.
| section_title =  
| summary_text = 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. Mutations in OCA2 result in type 2 oculocutaneous albinism.<ref name="entrez">{{cite web | title = Entrez Gene: OCA2 oculocutaneous albinism II (pink-eye dilution homolog, mouse)| url = http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=4948| accessdate = }}</ref>
}}


A mutation in the OCA2 is found common to nearly all people with [[blue eyes]], and has made the theory that all blue eyed humans share a single common ancestor with whom the mutation originated. <ref>[http://www.msnbc.msn.com/id/22934464/wid/11915773?GT1=10815#storyContinued MSNBC "Genetic mutation makes those brown eyes blue"], [http://www.livescience.com/health/080131-blue-eyes.html Livescience.com "One Common Ancestor Behind Blue Eyes"], [http://www.ku.dk/english/news/?content=http://www.ku.dk/english/news/blue-eyes.htm University of Copenhagen "Blue-eyed humans have a single, common ancestor"]</ref>
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 [[iris stroma]] (large amounts giving rise to brown eyes; little to no melanin giving rise to blue eyes).


==References==
== Clinical significance ==
{{reflist|2}}
[[File:OCA2 labels S.png|thumb|right|Global frequency distribution of the OCA2 gene's ancestral allele (blue) and derived ''His615Arg'' allele (yellow).]]
==Further reading==
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]] caused by mutations in the OCA2 gene is called '''oculocutaneous albinism type 2'''. The prevalence of OCA type 2 is estimated at 1/38,000-1/40,000 in most populations throughout the world, with a higher prevalence in the African population of 1/3,900-1/1,500.<ref>{{cite web |url=http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=79432 |title=Oculocutaneous albinism type 2 |last1=Hayashi |first1=Masahiro |last2=Suzuki |first2=Tamio |date=April 2013 |website=[[Orphanet]] |publisher= |accessdate=2014-11-09}}</ref> 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.<ref>{{cite web|title=OCA2 - oculocutaneous albinism II|url=http://ghr.nlm.nih.gov/gene/OCA2|work=Genetics Home Reference - Your guide to understanding genetic conditions|publisher=U.S. National Library of Medicine|accessdate=30 March 2013}}</ref><ref>{{cite web|title=Don't it make your brown eyes blue?|url=http://genetics.thetech.org/original_news/news39|work=Understanding Genetics|publisher=Understanding Genetics|accessdate=30 March 2013}}</ref>
{{refbegin | 2}}
{{PBB_Further_reading
| citations =
*{{cite journal  | author=Oetting WS, King RA |title=Molecular basis of albinism: mutations and polymorphisms of pigmentation genes associated with albinism. |journal=Hum. Mutat. |volume=13 |issue= 2 |pages= 99-115 |year= 1999 |pmid= 10094567 |doi= 10.1002/(SICI)1098-1004(1999)13:2<99::AID-HUMU2>3.0.CO;2-C }}
*{{cite journal  | author=Brilliant MH |title=The mouse p (pink-eyed dilution) and human P genes, oculocutaneous albinism type 2 (OCA2), and melanosomal pH. |journal=Pigment Cell Res. |volume=14 |issue= 2 |pages= 86-93 |year= 2001 |pmid= 11310796 |doi=  }}
*{{cite journal  | author=Ramsay M, Colman MA, Stevens G, ''et al.'' |title=The tyrosinase-positive oculocutaneous albinism locus maps to chromosome 15q11.2-q12. |journal=Am. J. Hum. Genet. |volume=51 |issue= 4 |pages= 879-84 |year= 1992 |pmid= 1415228 |doi=  }}
*{{cite journal  | author=Gardner JM, Nakatsu Y, Gondo Y, ''et al.'' |title=The mouse pink-eyed dilution gene: association with human Prader-Willi and Angelman syndromes. |journal=Science |volume=257 |issue= 5073 |pages= 1121-4 |year= 1992 |pmid= 1509264 |doi=  }}
*{{cite journal  | author=Ludowese CJ, Thompson KJ, Sekhon GS, Pauli RM |title=Absence of predictable phenotypic expression in proximal 15q duplications. |journal=Clin. Genet. |volume=40 |issue= 3 |pages= 194-201 |year= 1992 |pmid= 1773534 |doi=  }}
*{{cite journal  | author=Lee ST, Nicholls RD, Jong MT, ''et al.'' |title=Organization and sequence of the human P gene and identification of a new family of transport proteins. |journal=Genomics |volume=26 |issue= 2 |pages= 354-63 |year= 1995 |pmid= 7601462 |doi= }}
*{{cite journal  | author=Spritz RA, Fukai K, Holmes SA, Luande J |title=Frequent intragenic deletion of the P gene in Tanzanian patients with type II oculocutaneous albinism (OCA2). |journal=Am. J. Hum. Genet. |volume=56 |issue= 6 |pages= 1320-3 |year= 1995 |pmid= 7762554 |doi= }}
*{{cite journal  | author=Lee ST, Nicholls RD, Schnur RE, ''et al.'' |title=Diverse mutations of the P gene among African-Americans with type II (tyrosinase-positive) oculocutaneous albinism (OCA2). |journal=Hum. Mol. Genet. |volume=3 |issue= 11 |pages= 2047-51 |year= 1995 |pmid= 7874125 |doi=  }}
*{{cite journal  | author=Durham-Pierre D, Gardner JM, Nakatsu Y, ''et al.'' |title=African origin of an intragenic deletion of the human P gene in tyrosinase positive oculocutaneous albinism. |journal=Nat. Genet. |volume=7 |issue= 2 |pages= 176-9 |year= 1994 |pmid= 7920637 |doi= 10.1038/ng0694-176 }}
*{{cite journal  | author=Lee ST, Nicholls RD, Bundey S, ''et al.'' |title=Mutations of the P gene in oculocutaneous albinism, ocular albinism, and Prader-Willi syndrome plus albinism. |journal=N. Engl. J. Med. |volume=330 |issue= 8 |pages= 529-34 |year= 1994 |pmid= 8302318 |doi=  }}
*{{cite journal  | author=Rinchik EM, Bultman SJ, Horsthemke B, ''et al.'' |title=A gene for the mouse pink-eyed dilution locus and for human type II oculocutaneous albinism. |journal=Nature |volume=361 |issue= 6407 |pages= 72-6 |year= 1993 |pmid= 8421497 |doi= 10.1038/361072a0 }}
*{{cite journal  | author=Spritz RA, Lee ST, Fukai K, ''et al.'' |title=Novel mutations of the P gene in type II oculocutaneous albinism (OCA2). |journal=Hum. Mutat. |volume=10 |issue= 2 |pages= 175-7 |year= 1997 |pmid= 9259203 |doi= 10.1002/(SICI)1098-1004(1997)10:2<175::AID-HUMU12>3.0.CO;2-X }}
*{{cite journal  | author=Kerr R, Stevens G, Manga P, ''et al.'' |title=Identification of P gene mutations in individuals with oculocutaneous albinism in sub-Saharan Africa. |journal=Hum. Mutat. |volume=15 |issue= 2 |pages= 166-72 |year= 2000 |pmid= 10649493 |doi= 10.1002/(SICI)1098-1004(200002)15:2<166::AID-HUMU5>3.0.CO;2-Z }}
*{{cite journal  | author=Oetting WS, Gardner JM, Fryer JP, ''et al.'' |title=Mutations of the human P gene associated with Type II oculocutaneous albinism (OCA2). Mutations in brief no. 205. Online. |journal=Hum. Mutat. |volume=12 |issue= 6 |pages= 434 |year= 2000 |pmid= 10671067 |doi= 10.1002/(SICI)1098-1004(1998)12:6<434::AID-HUMU16>3.0.CO;2-7 }}
*{{cite journal  | author=Passmore LA, Kaesmann-Kellner B, Weber BH |title=Novel and recurrent mutations in the tyrosinase gene and the P gene in the German albino population. |journal=Hum. Genet. |volume=105 |issue= 3 |pages= 200-10 |year= 2000 |pmid= 10987646 |doi=  }}
*{{cite journal  | author=Manga P, Kromberg J, Turner A, ''et al.'' |title=In Southern Africa, brown oculocutaneous albinism (BOCA) maps to the OCA2 locus on chromosome 15q: P-gene mutations identified. |journal=Am. J. Hum. Genet. |volume=68 |issue= 3 |pages= 782-7 |year= 2001 |pmid= 11179026 |doi= }}
*{{cite journal  | author=Manga P, Orlow SJ |title=Inverse correlation between pink-eyed dilution protein expression and induction of melanogenesis by bafilomycin A1. |journal=Pigment Cell Res. |volume=14 |issue= 5 |pages= 362-7 |year= 2002 |pmid= 11601658 |doi=  }}
*{{cite journal  | author=Toyofuku K, Valencia JC, Kushimoto T, ''et al.'' |title=The etiology of oculocutaneous albinism (OCA) type II: the pink protein modulates the processing and transport of tyrosinase. |journal=Pigment Cell Res. |volume=15 |issue= 3 |pages= 217-24 |year= 2002 |pmid= 12028586 |doi=  }}
}}
{{refend}}


{{protein-stub}}
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 [[Eye color#Blue|blue eyes]]. It has been hypothesized that all blue-eyed humans share a single common ancestor with whom the mutation originated.<ref name="OCA2_blue_eyes_press">{{cite web | url = http://www.msnbc.msn.com/id/22934464/wid/11915773?GT1=10815#storyContinued | title = Here's what made those brown eyes blue  | author = Bryner J | authorlink = | coauthors = | date = 2008-01-31 | format = | work =  Health News| publisher = MSNBC | pages = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-06}}; {{cite web | url = http://www.livescience.com/health/080131-blue-eyes.html | title = One Common Ancestor Behind Blue Eyes | author = Bryner J | authorlink = | coauthors = | date = 2008-01-31 | work = LiveScience | publisher = Imaginova Corp. | pages = | archiveurl = | archivedate = | quote = | accessdate = 2008-11-06}}; {{cite web | url = http://www.ku.dk/english/news/?content=http://www.ku.dk/english/news/blue-eyes.htm | title = Blue-eyed humans have a single, common ancestor | date = 2008-01-30 | work = News | publisher = University of Copenhagen | accessdate = 2008-11-06}}</ref><ref name="pmid18172690">{{cite journal | vauthors = Eiberg H, Troelsen J, Nielsen M, Mikkelsen A, Mengel-From J, Kjaer KW, Hansen L | title = Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression | journal = Hum. Genet. | volume = 123 | issue = 2 | pages = 177–87 | year = 2008 | pmid = 18172690 | doi = 10.1007/s00439-007-0460-x }}</ref><ref name="pmid18252222">{{cite journal | vauthors = Sturm RA, Duffy DL, Zhao ZZ, Leite FP, Stark MS, Hayward NK, Martin NG, Montgomery GW | title = A single SNP in an evolutionary conserved region within intron 86 of the HERC2 gene determines human blue-brown eye color | journal = Am. J. Hum. Genet. | volume = 82 | issue = 2 | pages = 424–31 | year = 2008 | pmid = 18252222 | pmc = 2427173 | doi = 10.1016/j.ajhg.2007.11.005 }}</ref>
{{WikiDoc Sources}}
 
The ''His615Arg'' [[allele]] of OCA2 is involved in the light skin tone and the derived allele is restricted to East Asia with high frequencies, with highest frequencies in Eastern East Asia (49-63%), midrange frequencies in Southeast Asia, and the lowest frequencies in Western China and some Eastern European populations.<ref name="pmid22065085">{{cite journal | vauthors = Donnelly MP, Paschou P, Grigorenko E, Gurwitz D, Barta C, Lu RB, Zhukova OV, Kim JJ, Siniscalco M, New M, Li H, Kajuna SL, Manolopoulos VG, Speed WC, Pakstis AJ, Kidd JR, Kidd KK | title = A global view of the OCA2-HERC2 region and pigmentation | journal = Hum. Genet. | volume = 131 | issue = 5 | pages = 683–96 | year = 2012 | pmid = 22065085 | pmc = 3325407 | doi = 10.1007/s00439-011-1110-x }}</ref><ref name="Edwards_2010">{{cite journal | vauthors = Edwards M, Bigham A, Tan J, Li S, Gozdzik A, Ross K, Jin L, Parra EJ | title = Association of the OCA2 polymorphism His615Arg with melanin content in east Asian populations: further evidence of convergent evolution of skin pigmentation | journal = PLoS Genet. | volume = 6 | issue = 3 | pages = e1000867 | year = 2010 | pmid = 20221248 | pmc = 2832666 | doi = 10.1371/journal.pgen.1000867 }}</ref>
 
== References ==
{{Reflist|35em}}
 
== Further reading ==
{{Refbegin|35em}}
* {{cite journal | vauthors = Oetting WS, King RA | title = Molecular basis of albinism: mutations and polymorphisms of pigmentation genes associated with albinism | journal = Hum. Mutat. | volume = 13 | issue = 2 | pages = 99–115 | year = 1999 | pmid = 10094567 | doi = 10.1002/(SICI)1098-1004(1999)13:2<99::AID-HUMU2>3.0.CO;2-C }}
* {{cite journal | vauthors = Brilliant MH | title = The mouse p (pink-eyed dilution) and human P genes, oculocutaneous albinism type 2 (OCA2), and melanosomal pH | journal = Pigment Cell Res. | volume = 14 | issue = 2 | pages = 86–93 | year = 2001 | pmid = 11310796 | doi = 10.1034/j.1600-0749.2001.140203.x }}
* {{cite journal | vauthors = Ramsay M, Colman MA, Stevens G, Zwane E, Kromberg J, Farrall M, Jenkins T | title = The tyrosinase-positive oculocutaneous albinism locus maps to chromosome 15q11.2-q12 | journal = Am. J. Hum. Genet. | volume = 51 | issue = 4 | pages = 879–84 | year = 1992 | pmid = 1415228 | pmc = 1682821 | doi =  }}
* {{cite journal | vauthors = Gardner JM, Nakatsu Y, Gondo Y, Lee S, Lyon MF, King RA, Brilliant MH | title = The mouse pink-eyed dilution gene: association with human Prader-Willi and Angelman syndromes | journal = Science | volume = 257 | issue = 5073 | pages = 1121–4 | year = 1992 | pmid = 1509264 | doi = 10.1126/science.257.5073.1121 }}
* {{cite journal | vauthors = Ludowese CJ, Thompson KJ, Sekhon GS, Pauli RM | title = Absence of predictable phenotypic expression in proximal 15q duplications | journal = Clin. Genet. | volume = 40 | issue = 3 | pages = 194–201 | year = 1991 | pmid = 1773534 | doi = 10.1111/j.1399-0004.1991.tb03076.x }}
* {{cite journal | vauthors = Lee ST, Nicholls RD, Jong MT, Fukai K, Spritz RA | title = Organization and sequence of the human P gene and identification of a new family of transport proteins | journal = Genomics | volume = 26 | issue = 2 | pages = 354–63 | year = 1995 | pmid = 7601462 | doi = 10.1016/0888-7543(95)80220-G }}
* {{cite journal | vauthors = Spritz RA, Fukai K, Holmes SA, Luande J | title = Frequent intragenic deletion of the P gene in Tanzanian patients with type II oculocutaneous albinism (OCA2) | journal = Am. J. Hum. Genet. | volume = 56 | issue = 6 | pages = 1320–3 | year = 1995 | pmid = 7762554 | pmc = 1801108 | doi =  }}
* {{cite journal | vauthors = Lee ST, Nicholls RD, Schnur RE, Guida LC, Lu-Kuo J, Spinner NB, Zackai EH, Spritz RA | title = Diverse mutations of the P gene among African-Americans with type II (tyrosinase-positive) oculocutaneous albinism (OCA2) | journal = Hum. Mol. Genet. | volume = 3 | issue = 11 | pages = 2047–51 | year = 1994 | pmid = 7874125 | doi =  }}
* {{cite journal | vauthors = Durham-Pierre D, Gardner JM, Nakatsu Y, King RA, Francke U, Ching A, Aquaron R, del Marmol V, Brilliant MH | title = African origin of an intragenic deletion of the human P gene in tyrosinase positive oculocutaneous albinism | journal = Nat. Genet. | volume = 7 | issue = 2 | pages = 176–9 | year = 1994 | pmid = 7920637 | doi = 10.1038/ng0694-176 }}
* {{cite journal | vauthors = Lee ST, Nicholls RD, Bundey S, Laxova R, Musarella M, Spritz RA | title = Mutations of the P gene in oculocutaneous albinism, ocular albinism, and Prader-Willi syndrome plus albinism | journal = N. Engl. J. Med. | volume = 330 | issue = 8 | pages = 529–34 | year = 1994 | pmid = 8302318 | doi = 10.1056/NEJM199402243300803 }}
* {{cite journal | vauthors = Rinchik EM, Bultman SJ, Horsthemke B, Lee ST, Strunk KM, Spritz RA, Avidano KM, Jong MT, Nicholls RD | title = A gene for the mouse pink-eyed dilution locus and for human type II oculocutaneous albinism | journal = Nature | volume = 361 | issue = 6407 | pages = 72–6 | year = 1993 | pmid = 8421497 | doi = 10.1038/361072a0 }}
* {{cite journal | vauthors = Spritz RA, Lee ST, Fukai K, Brondum-Nielsen K, Chitayat D, Lipson MH, Musarella MA, Rosenmann A, Weleber RG | title = Novel mutations of the P gene in type II oculocutaneous albinism (OCA2) | journal = Hum. Mutat. | volume = 10 | issue = 2 | pages = 175–7 | year = 1997 | pmid = 9259203 | doi = 10.1002/(SICI)1098-1004(1997)10:2<175::AID-HUMU12>3.0.CO;2-X }}
* {{cite journal | vauthors = Kerr R, Stevens G, Manga P, Salm S, John P, Haw T, Ramsay M | title = Identification of P gene mutations in individuals with oculocutaneous albinism in sub-Saharan Africa | journal = Hum. Mutat. | volume = 15 | issue = 2 | pages = 166–72 | year = 2000 | pmid = 10649493 | doi = 10.1002/(SICI)1098-1004(200002)15:2<166::AID-HUMU5>3.0.CO;2-Z }}
* {{cite journal | vauthors = Oetting WS, Gardner JM, Fryer JP, Ching A, Durham-Pierre D, King RA, Brilliant MH | title = Mutations of the human P gene associated with Type II oculocutaneous albinism (OCA2). Mutations in brief no. 205. Online | journal = Hum. Mutat. | volume = 12 | issue = 6 | pages = 434 | year = 1998 | pmid = 10671067 | doi = 10.1002/(SICI)1098-1004(1998)12:6<434::AID-HUMU16>3.0.CO;2-7 }}
* {{cite journal | vauthors = Passmore LA, Kaesmann-Kellner B, Weber BH | title = Novel and recurrent mutations in the tyrosinase gene and the P gene in the German albino population | journal = Hum. Genet. | volume = 105 | issue = 3 | pages = 200–10 | year = 1999 | pmid = 10987646 | doi = 10.1007/s004390051090 }}
* {{cite journal | vauthors = Manga P, Kromberg J, Turner A, Jenkins T, Ramsay M | title = In Southern Africa, brown oculocutaneous albinism (BOCA) maps to the OCA2 locus on chromosome 15q: P-gene mutations identified | journal = Am. J. Hum. Genet. | volume = 68 | issue = 3 | pages = 782–7 | year = 2001 | pmid = 11179026 | pmc = 1274491 | doi = 10.1086/318800 }}
* {{cite journal | vauthors = Manga P, Orlow SJ | title = Inverse correlation between pink-eyed dilution protein expression and induction of melanogenesis by bafilomycin A1 | journal = Pigment Cell Res. | volume = 14 | issue = 5 | pages = 362–7 | year = 2001 | pmid = 11601658 | doi = 10.1034/j.1600-0749.2001.140508.x }}
* {{cite journal | vauthors = Toyofuku K, Valencia JC, Kushimoto T, Costin GE, Virador VM, Vieira WD, Ferrans VJ, Hearing VJ | title = The etiology of oculocutaneous albinism (OCA) type II: the pink protein modulates the processing and transport of tyrosinase | journal = Pigment Cell Res. | volume = 15 | issue = 3 | pages = 217–24 | year = 2002 | pmid = 12028586 | doi = 10.1034/j.1600-0749.2002.02007.x }}
{{Refend}}
 
== External links ==
{{Commons category|OCA2}}
* [https://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=oca2  GeneReviews/NCBI/NIH/UW entry on Oculocutaneous Albinism Type 2]
 
[[Category:Genes on human chromosome 15]]

Revision as of 00:20, 7 September 2017

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Orthologs
SpeciesHumanMouse
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View/Edit Human

P protein, also known as melanocyte-specific transporter protein or pink-eyed dilution protein homolog, is a protein that in humans is encoded by the oculocutaneous albinism II (OCA2) gene.[1] 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.[1] OCA2 encodes the human homologue of the mouse p (pink-eyed dilution) gene.

File:OCA2 gene location.png
In human, the OCA2 gene is located on the long (q) arm of chromosome 15 between positions 12 and 13.1

The human 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.

Function

OCA2 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 iris stroma (large amounts giving rise to brown eyes; little to no melanin giving rise to blue eyes).

Clinical significance

File:OCA2 labels S.png
Global frequency distribution of the OCA2 gene's ancestral allele (blue) and derived His615Arg allele (yellow).

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 caused by mutations in the OCA2 gene is called oculocutaneous albinism type 2. The prevalence of OCA type 2 is estimated at 1/38,000-1/40,000 in most populations throughout the world, with a higher prevalence in the African population of 1/3,900-1/1,500.[2] 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.[3][4]

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.[5][6][7]

The His615Arg allele of OCA2 is involved in the light skin tone and the derived allele is restricted to East Asia with high frequencies, with highest frequencies in Eastern East Asia (49-63%), midrange frequencies in Southeast Asia, and the lowest frequencies in Western China and some Eastern European populations.[8][9]

References

  1. ↑ 1.0 1.1 "Entrez Gene: OCA2 oculocutaneous albinism II (pink-eye dilution homolog, mouse)". Retrieved 2015-03-12.
  2. ↑ Hayashi, Masahiro; Suzuki, Tamio (April 2013). "Oculocutaneous albinism type 2". Orphanet. Retrieved 2014-11-09.
  3. ↑ "OCA2 - oculocutaneous albinism II". Genetics Home Reference - Your guide to understanding genetic conditions. U.S. National Library of Medicine. Retrieved 30 March 2013.
  4. ↑ "Don't it make your brown eyes blue?". Understanding Genetics. Understanding Genetics. Retrieved 30 March 2013.
  5. ↑ Bryner J (2008-01-31). "Here's what made those brown eyes blue". Health News. MSNBC. Retrieved 2008-11-06.; Bryner J (2008-01-31). "One Common Ancestor Behind Blue Eyes". LiveScience. Imaginova Corp. Retrieved 2008-11-06.; "Blue-eyed humans have a single, common ancestor". News. University of Copenhagen. 2008-01-30. Retrieved 2008-11-06.
  6. ↑ Eiberg H, Troelsen J, Nielsen M, Mikkelsen A, Mengel-From J, Kjaer KW, Hansen L (2008). "Blue eye color in humans may be caused by a perfectly associated founder mutation in a regulatory element located within the HERC2 gene inhibiting OCA2 expression". Hum. Genet. 123 (2): 177–87. doi:10.1007/s00439-007-0460-x. PMID 18172690.
  7. ↑ Sturm RA, Duffy DL, Zhao ZZ, Leite FP, Stark MS, Hayward NK, Martin NG, Montgomery GW (2008). "A single SNP in an evolutionary conserved region within intron 86 of the HERC2 gene determines human blue-brown eye color". Am. J. Hum. Genet. 82 (2): 424–31. doi:10.1016/j.ajhg.2007.11.005. PMC 2427173. PMID 18252222.
  8. ↑ Donnelly MP, Paschou P, Grigorenko E, Gurwitz D, Barta C, Lu RB, Zhukova OV, Kim JJ, Siniscalco M, New M, Li H, Kajuna SL, Manolopoulos VG, Speed WC, Pakstis AJ, Kidd JR, Kidd KK (2012). "A global view of the OCA2-HERC2 region and pigmentation". Hum. Genet. 131 (5): 683–96. doi:10.1007/s00439-011-1110-x. PMC 3325407. PMID 22065085.
  9. ↑ Edwards M, Bigham A, Tan J, Li S, Gozdzik A, Ross K, Jin L, Parra EJ (2010). "Association of the OCA2 polymorphism His615Arg with melanin content in east Asian populations: further evidence of convergent evolution of skin pigmentation". PLoS Genet. 6 (3): e1000867. doi:10.1371/journal.pgen.1000867. PMC 2832666. PMID 20221248.

Further reading

External links

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