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 [1] (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 [2] (203100 [3], 606952 [4]), OCA2 [5] (203200 [6]), and OCA4 [7] (606574 [8]).

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 [9]

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

PubMed ID:

17980020

Rufous oculocutaneous albinism in southern African Blacks is caused by mutations in the TYRP1 gene [10]

Manga P, Kromberg JG, Box NF, Sturm RA, Jenkins T, Ramsay M. Rufous oculocutaneous albinism in southern African Blacks is caused by mutations in the TYRP1 gene. Am J Hum Genet. 1997 Nov;61(5):1095-101.

PubMed ID:

9345097

Brown oculocutaneous albinism. Clinical, ophthalmological, and biochemical characterization [11]

King RA, Lewis RA, Townsend D, Zelickson A, Olds DP, Brumbaugh J. Brown oculocutaneous albinism. Clinical, ophthalmological, and biochemical characterization. Ophthalmology. 1985 Nov;92(11):1496-505.

PubMed ID:

3935994