Oculocutaneous albinism type 3

Alternate names

OCA3; Albinism, oculocutaneous, type 3; Albinism 3

Definition

Type 3 oculocutaneous albinism (OCA3) is a form of oculocutaneous albinism (OCA) characterized by rufous or brown albinism and occurring mainly in the African population.

Epidemiology

OCA3 has an estimated prevalence of 1/8,500 individuals in Africa. It is rarely seen in other populations.

Cause

OCA3 is caused by a mutation in the tyrosinase-related protein 1, TYRP1, gene located on chromosome 9p23. The majority of BOCA cases are seen in OCA2, but a few BOCA phenotypes have been reported with mutations in the TYRP1 gene, indicating OCA3.

Inheritance

Autosomal recessive inheritance, a 25% chance

OCA3 is inherited autosomal recessively and genetic counseling is possible.

Signs and symptoms

Visual anomalies, such as nystagmus, are frequently undetectable and patients usually present with one of two phenotypes: rufous OCA (ROCA), characterized by red-bronze skin color, blue or brown irises and ginger-red hair, or brown OCA (BOCA), characterized by light to brown hair and a light to brown or tan skin color. The clinical features of OCA3 have been considered as rather mild, and in the rare cases of non-African patients, reddish hair color has been reported. A Japanese girl was reported with having OCA3 who presented with blond hair and light skin (with a small Mongolian spot), was able to tan and was negative for nystagmus.

For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. 80%-99% of people have these symptoms

• Albinism
• Iris hypopigmentation(Light eye color)
• Nystagmus(Involuntary, rapid, rhythmic eye movements)

30%-79% of people have these symptoms

• Freckling
• Red hair(Red hair color)
• Strabismus(Cross-eyed)

5%-29% of people have these symptoms

• Cutaneous photosensitivity(Photosensitive skin)