oculocutaneous albinism type 4

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oculocutaneous albinism type 4

An inherited disorder of pigmentation (OMIM:606574) characterised by reduced biosynthesis of melanin in the skin, hair and eyes, and classic albinism-type ocular abnormalities: decreased visual acuity, macular hypoplasia, optic dysplasia, atypical choroidal vessels and nystagmus.

Molecular pathology
OCA4 is caused by a mutation of SLC45A2 on chromosome 5p13.2, which encodes a transporter protein that mediates melanin synthesis.
References in periodicals archive ?
Prevalence rate of different genetic forms of OCA among the various world populations has determined OCA1 as the most widespread type of loci mapped among the Caucasian patients followed by OCA2 OCA4 and OCA3 respectively3.
Genetic analysis of families with inherited OCA so far has identified seven loci and six genes including; OCA1 (TYR) OCA2 (OCA2) OCA3 (TYRP1) OCA4 (SLC45A2) OCA5 OCA6 (SLC24A5) and OCA7 (C10orf11).
Pathogenic sequence change in SLC45A2 (MIM# 606202) gene is the cause of OCA4 condition.
There are four major forms: (i) OCA1 (mutated tyrosinase (TYR) gene); [12] (ii) OCA2 (mutated OCA2 gene); [13] (iii) OCA3 (mutated tyrosinase-related protein 1 (TYRP1) gene); [14] and (iv) OCA4 (mutated solute carrier family 45, member 2 (SLC45A2) gene).
Mutations in the human orthologue of the mouse underwhite gene (uw) underlie a new form of oculocutaneous albinism, OCA4.
3 AR albinism OCA2 15q12--q13 AR OCA3 TYRP1 9p23 AR OCA4 MATP 5p13.
9p23 lokusundaki TYRP1 (tyrosinase-related protein 1) genindeki mutasyon sonucu gorulen OCA3 (tip 3) ve 5p'deki SLC45A2 (eski adiyla MATP) geninde resesif ozellikte mutasyon sonucu gorulen OCA4 nadir okulokutanoz albinizm tipleridir.