Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 606281 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Disease-related: no

Key variant known: yes

Year key variant first reported: 2015

Key variant is published: no

Species-specific symbol: OH

History: As reported by Hollman et al. (2017), via a personal communication from Dr Jon Beever, "Recently an alteration of iris coloration has been observed in Angus and Simmental breed. Affected cattle showed an oculocutaneous hypopigmentation (OH) with a pale blue iris and a tan periphery coupled with a change in coat color from black to chocolate. It is assumed that this aberration was introduced into the Simmental breed in the late 1950s by Angus founders and is inherited as an autosomal recessive trait." As described by Dr Beever in a 2015 press release from the American Simmental Association (Anon., 2015), "In the spring of 2012, the American Simmental Association (ASA) received an abnormality report indicating the occurrence of a newborn calf with “white-colored” eyes and a diluted hair coat (see picture at right)."

Molecular basis: As reported by Hollman et al. (2017), via a personal communication from Dr Jon Beever, "An amino acid exchange in the Ras-related Protein Rab-38 (RAB38) gene was identified as the disease causing mutation". A 2015 press release from the American Simmental Association (Anon., 2015) reported "Recently Dr. Beever has found the causative mutation and developed a diagnostic test for OH." It appears that the mutation arose originally in Angus cattle (Anon., 2015; https://www.angus.org/pub/OH/OHInfo.aspx).

Breeds: Angus (Cattle) (VBO_0000104), Simmental (Cattle) (VBO_0000380).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).

Associated gene: