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Gene: TYR

Green List (high evidence)

Two types of OCA1 are described in the literature. OCA1A is the most severe form of the disorder. Tyrosinase activity is completely absent and melanin pigment cannot be detected in the skin, hair or eyes of individuals with OCA1. There is low tyrosinase activity in individuals with OCA1B, but some residual activity is present allowing some melanin to be produced, albeit at a reduced amount. There is a MONDO lumping the two types: oculocutaneous albinism type 1 (MONDO:0018135).

Congenital onset. Well established gene-disease association.

OCA1A is caused by null variants that produce a completely inactive enzyme. OCA1B results from partially inactive enzymes (hom or c.het even with a null variant). Most reports are biallelic, the AD phenotypes don't appear very solid, with the same reports pertaining to the same variants occurring in cis or by itself, and in older papers.

Created: 6 Feb 2025, 3:19 a.m. | Last Modified: 6 Feb 2025, 3:19 a.m.

Panel Version: 1.1459

Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal

Phenotypes
Oculocutaneous albinism type 1 (MONDO:0018135); Albinism, oculocutaneous, type IA, MIM#203100; Albinism, oculocutaneous, type IB, MIM#606952

Publications

• 30868138
• 37053367