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It is important to note that having a risk factor does not mean that one will get the
condition. A risk factor increases one’s chances of getting a condition compared to an
individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the
condition. It is always important to discuss the effect of risk factors with your
healthcare provider.

What are the Causes of Oculocutaneous Albinism? (Etiology)

Oculocutaneous Albinism is caused by mutation(s) in at least 7 genes involved in the
production and distribution of the pigment melanin. The specific gene mutation forms
the basis of the classification of OCA into 7 subtypes:

 OCA1, or tyrosine-related albinism, results from a mutation in the gene coding
for the enzyme tyrosinase, which catalyzes conversion of the amino acid
tyrosine to melanin. There are 2 sub-forms of OCA1:

o OCA1A - it is characterized by the absence of tyrosinase
o OCA1B - in which individuals produce low amounts of the enzyme
 OCA2 is caused by defects in the OCA2 gene coding for P protein, which
facilitates tyrosinase action. Individuals with OCA2 produce melanin in reduced
quantities
 OCA3, a rare disorder, develops as a result of mutation(s) in TYRP1 gene,
which codes for a protein associated with tyrosinase. The pigmentation in
individuals with OCA3 may not be very low
 OCA4 is caused by defects in the SLC45A2 gene. The protein coded by this
gene facilitates the function of tyrosinase, and the affected individuals have
decreased melanin synthesis, similar to OCA2
 OCA5 has been mapped to chromosome 4, and is a rare subtype of OCA
 OCA6 is a rare disorder, and is caused by mutations in the SLC24A5 gene
 OCA7 is also rare, and is caused by mutations in the C10orf11 gene

All forms of Oculocutaneous Albinism are inherited in an autosomal recessive pattern.
In this type of inheritance, an individual must possess both copies of the causative
gene in the defective form in every cell of his/her body for the condition to manifest
itself. An affected individual inherits one defective copy from each parent. The parents
are carriers of the condition and are generally not affected.

References

https://www.dovemed.com/diseases-

conditions/oculocutaneous-albinism/