Oculocutaneous albinism type I or type 1A  is an autosomal recessive skin disease. This subtype of oculocutaneous albinism is caused when the gene for tyrosinase (symbol TYR or OCA1) does not function properly. The location of OCA1 may be written as "11q1.4-q2.1", meaning it is on chromosome 11, long arm, somewhere in the range of band 1, sub-band 4, and band 2, sub-band 1. Since the disorder is autosomal recessive, genetic counseling can be used to determine if both parents are heterozygous for the condition when considering having children. If both parents are heterozygous, their child has a 25% chance of inheriting both recessive copies of OCA1 and having the skin disease.This symptoms in this disease include absence of pigmentation, due to a mutation that affects melanin levels in the eyes, hair, and skin. This rare disease is found in 1 out of 20,000 people around the world, being much more prevalent in Caucasians. There is no known cure for this disease as of present, but there are various ways to manage this disease, including safety around the sun and regular checks for other skin diseases such as skin cancer. Signs and Symptoms
OCA is characterized by the absence of pigmentation caused by the mutation that effects the production of tyrosinase that causes partial or total absence of melanin in the hair, skin, and eyes.
Individuals affected by OCA1A should be attentive to the amount of sun exposure they experience and wear proper protection such as clothing that covers the skin. Additionally, individuals may need corrective visual aids for their visual acuity of 1/10 or less with intense photophobia. Visual aids can both improve vision or protect eyes from bright lights. These visual aids can be adjusted for based on individual needs. Individuals should receive annual skin evaluation to access for damage or skin cancers that can be induced from sun exposure. In some situations, therapy or surgery can correct crossed eyes (strabismus) or rapid eye movements (nystagmus). Epidemiology
The highest frequency of Albinism type IA is in Northern Ireland, with a phenotype frequency of around 1: 10,000. First cousin - marriages accounted for 4.5% of the parents of patients. Additionally, symptoms that could be heterozygous mutations, such as abnormal iris translucency occurred in 70% of the parents and children of individuals affected with this condition. In general, the phenotypical appearance of OCA1A is associated with northern and western Europe. This is because over 50% of OCA1 subjects are Caucasians. OCA1 is also the most common form of Albinism in China and Japan. The overall frequency is 1: 20,000 people in the world. References


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