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oculocutaneous albinisms

Monday 22 September 2003

The heterogeneous group of disorders known as oculocutaneous albinisms (OCAs) shares cutaneous and ocular hypopigmentation associated with common developmental abnormalities of the eye. Mutations of at least 11 loci produce this phenotype.

The majority of affected individuals develop some cutaneous melanin; this is predominantly seen as yellow/blond hair, whereas fewer have brown hair. The OCA phenotype is dependent on the constitutional pigmentation background of the family, with more OCA pigmentation found in families with darker constitutional pigmentation, which indicates that other genes may modify the OCA phenotype.

There is four kown types of OCA:

- OCA1 (11q14-q21) (MIM.203100)

  • OCA1A
  • OCA1B

- OCA2 : mutation of the P protein gene (15q11)(MIM.203200)
- OCA3 (9p23) (MIM.203290)
- OCA4


- OCA2: deletion in the P gene (12469324)
- sequence variations in the melanocortin-1 receptor (MC1R) gene (12876664)