A New TYR Splice Donor Variant Causing Oculocutaneous Albinism Type I in Angus Cattle

Oculocutaneous albinism type I is caused by variants in TYR , a key gene involved in melanin biosynthesis. Here, we report the identification of a novel splice donor variant in TYR (NM_181001.3:c.1184+1G>C) in two affected Angus cattle using whole genome sequencing. This represents the first reported TYR variant associated with oculocutaneous albinism in the Angus breed and expands the known genetic basis of pigmentation disorders in cattle. Variants in the TYR gene are known to cause autosomal recessive oculocutaneous albinism type I in multiple animal species (OMIA:000202) (Nicholas et al. 2025) and in humans (OMIM:606933) (Johns Hopkins University 2025). The TYR gene encodes tyrosinase, the rate-limiting enzyme in the melanin bio-synthesis pathway. Pathogenic variants in the TYR gene lead to a failure to produce pigmentation in the body and result in white hair, pale skin and light irises, as well as visual impairment due to disrupted eye development