Oculocutaneous Albinism

Often called classic albinism
OCA 1A Phenotype
1. Total absence of melanin
2. White hair, milky white skin, pale pink eyes at birth
3. Vision problems
The gene that causes classic albinism encodes the enzyme tyrosinase
1. Gene encoding tyrosinase is on chromosome 11
How common is classic albinism?
1. Incidence of Oculocutaneous Albinism OCA 1A
  1. 1 in 20,000 U.S. Caucasians are affected
  2. 1 in 10,000 in Ireland
  3. 1 in 200 Hopi (Arizona)
  4. 1 in 200 Zuni (New Mexico)
  5. 1 in 200 Cuna (Panama)
Temperature Sensitive OCA
1. Individuals produce a temperature-sensitive tyrosinase
2. Another allele, produces a tyrosinase with reduced activity
Oculocutaneous Albinism OCA 1B
1. Vision problems
2. Tyrosinase has reduced activity
Other genes can produce albinism
Oculocutaneous Albinism OCA2-P Gene
1. OCA2-P gene is located on chromosome 15
2. Most common type of albinism on the world
3. Gene phenotype
  1. Hair is yellow, can turn lighter in older individuals
  2. Skin is white
  3. Eyes are blue/grey
  4. Freckles can be present
4. Encodes a melanosomal membrane protein whose function is not understood

Zusammenfassung der Ressource

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