TYRP1

Albinism, Oculocutaneous, Type III

Clinical Characteristics
Ocular Features: 

The irides may be multicolored with the central potion light brown and the peripheral areas blue-gray.  Translucency of a punctate and radial nature is present.  Nystagmus is present in almost all cases and strabismus is present in nearly half.  Visual acuity is in the range of 20/60 to 20/200.   Photophobia is less severe than in other types of oculocutaneous albinism, possibly because the vast majority of individuals (86%) have some pigmentation in the fundus. 

Systemic Features: 

The hair in dark-skinned people may be medium brown while the skin is often light brown and subject to faint tanning.  However, the hair is often copper-red in color which has given rise to the designation rufous oculocutaneous albinism. 

Genetics

This tyrosinase-positive type of albinism is sometimes called 'rufous' (ROCA) or 'brown' (BOCA) oculocutaneous albinism and is frequently found in dark-skinned individual such as Africans, African-Americans, and Hispanics.  Like other types it is inherited in an autosomal recessive pattern.  Mutations in the tyrosinase-related protein-1, TYRP1 (9p23), are responsible which seems to lead to an arrest in melanin maturation and a decrease in the amount of insoluble melanin in melanocytes.

Other autosomal recessive types of oculocutaneous albinism are: OCA1 (203100, 606952), OCA2 (203200), and OCA4 (606574). 

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No treatment is available for the hypopigmentation.  However, precautions against excessive sun exposure are advised.  Low vision aids can be helpful. 

References
Article Title: 

Oculocutaneous albinism

Gronskov K, Ek J, Brondum-Nielsen K. Oculocutaneous albinism. Orphanet J Rare Dis. 2007 Nov 2;2:43. Review.

PubMed ID: 
17980020
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