OMIA 000202-452646 : Coat colour, oculocutaneous albinism type I (OCA1), TYR-related in Neovison vison

In other species: domestic cat , cattle , dog , rabbit , water buffalo , ass , Japanese medaka , humpback whale , domestic ferret , pig , domestic guinea pig , Tufted capuchin , dark-spotted frog , Japanese wrinkled frog , Rice frog , lion , Mongolian gerbil , red fox , hamadryas baboon , red deer , Japanese raccoon dog , Japanese ratsnake

Possibly relevant human trait(s) and/or gene(s)s (MIM numbers): 203100 , 606952 , 606933

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2008

Cross-species summary: Congenital lack of pigment in most parts of the body. Due to a non-functional form of the enzyme tyrosinase. Also known as Oculocutaneous albinism (OCA), Acromelanism and as the Himalayan coat-colour pattern

Species-specific description: Two mutant alleles have been characterized at the molecular level: albino (complete loss of function) and marbled or Himalayan (temperature-sensitive partial loss of function). The Himalayan phenotype is similar to that of the Siamese and Burmese cats: "light-colored body with dark-colored points (ears, face, tail, and feet)" (Benkel et al., 2009).

Inheritance: The predicted dominance hierarchy is: wildtype > Himalayan > albino

Mapping: Anistoroaei et al. (2008) linkage-mapped the albino locus in American mink to two microsatellites known to be located in the region of the mink genome homologous to the TYR gene in other species. They also physically mapped a BAC clone containing one of the two linked microsatellites (Mvi6034) "to chromosome 7q1.1-q1.3 by fluorescent in situ hybridization".

Molecular basis: By sequencing the strong comparative positional (see Mapping section) and functional candidate gene (TYR), Anistoroaei et al. (2008) showed that albinism in American Mink is due to "a nonsense mutation in exon 1, which converts a TGT codon encoding cysteine to a TGA stop codon (c.138T>A, p.C46X; EU627590). The mutation truncates more than 90% of the normal gene product including the putative catalytic domains."

By sequencing a very strong comparative and functional candidate gene, Benkel et al (2009) showed that "marbled mink carry a mutation in exon 4 of the TYR gene (c.1835C > G) which results in an amino acid substitution (p.H420Q). The location of this substitution corresponds to the amino acid position that is also mutated in the TYR protein of the Himalayan mouse. Thus, the marbled variant is more aptly referred to as the Himalayan mink."

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
TYR Neovison vison - no genomic information (-..-) TYR Ensembl

Variants

By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Breed(s) Variant Phenotype Gene Allele Type of Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
Albinism TYR nonsense (stop-gain) c.138T>A p.C46* 2008 18822100
Himalayan TYR missense c.1835C>G p.H420Q 2009 19308642

References


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.
2009 Benkel, BF., Rouvinen-Watt, K., Farid, H., Anistoroaei, R. :
Molecular characterization of the Himalayan mink. Mamm Genome 20:256-9, 2009. Pubmed reference: 19308642. DOI: 10.1007/s00335-009-9177-6.
2008 Anistoroaei, R., Fredholm, M., Christensen, K., Leeb, T. :
Albinism in the American mink (Neovison vison) is associated with a tyrosinase nonsense mutation. Anim Genet 39:645-8, 2008. Pubmed reference: 18822100. DOI: 10.1111/j.1365-2052.2008.01788.x.

Edit History


  • Created by Frank Nicholas on 09 Jul 2009
  • Changed by Frank Nicholas on 15 Sep 2011
  • Changed by Frank Nicholas on 12 Dec 2011
  • Changed by Frank Nicholas on 21 Mar 2012
  • Changed by Frank Nicholas on 05 Aug 2013
  • Changed by Frank Nicholas on 08 Nov 2013
  • Changed by Tosso Leeb on 24 Jun 2020