OMIA:000649-9940 : Microphthalmia in Ovis aries (sheep)

In other species: Nile tilapia , chicken , dog , pig , Eastern wapiti , taurine cattle , golden hamster , fox squirrel , Campbell's desert hamster , water buffalo

Categories: Vision / eye phene

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Considered a defect: yes

Key variant known: yes

Year key variant first reported: 2010

Cross-species summary: Abnormal smallness in all dimensions of one or both eyes.

Species-specific name: Hereditary ovine microphthalmia, OMO

Mapping: Becker et al. (2010) used the first-generation ovine SNP50 BeadChip to map this disorder to a 2.4 Mb region of chromosome OAE22. This region contains the gene PITX3, mutations in which cause some forms of this disorder in humans.

Molecular basis: Sequencing of the prime candidate gene PITX3 in affecteds and normals, by Becker et al. (2010), identified a missense mutation (338G>C, R113P) in a conserved region of the gene as being causative.

Prevalence: Goncalves et al. (2018) reported the occurrence of this disorder in four Texel lambs in Brazil. All four affected lambs were homozygous for the c.338G>C variant, and 16/61 of the flock were heterozygous, including the two ewes and two rams that were parents of the four affected lambs.

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
PITX3 paired-like homeodomain 3 Ovis aries 22 NC_056075.1 (22655542..22643947) PITX3 Homologene, Ensembl , NCBI gene


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.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
232 Texel (Sheep) Microphthalmia PITX3 missense Naturally occurring variant Oar_rambouillet_v1.0 22 g.25497953C>G c.338G>C p.(R113P) Oar_v3.1 position is g.22045744C>G 2010 20084168 Variant coordinates obtained from or confirmed by EBI's Some Effect Predictor (VEP) tool. The genomic location on Oar_rambouillet_v1.0 was determined by Katie Eager, EMAI, NSW Department of Primary Industries.

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2019). OMIA:000649-9940: Online Mendelian Inheritance in Animals (OMIA) [dataset].


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.

2018 Gonçalves, M.A., Pereira, P.R., Sales da Cruz, R.A., Panziera, W., Abranches de Andrade, D.G., Paes de Oliveira-Filho, J., Borges, A.S., Sonne, L., Driemeier, D. :
Hereditary microphthalmia in Texel lambs in Brazil Small Ruminant Research 160:1-4, 2018. DOI: 10.1016/j.smallrumres.2017.12.012.
2010 Becker, D., Tetens, J., Brunner, A., Bürstel, D., Ganter, M., Kijas, J., Drögemüller, C. :
Microphthalmia in Texel sheep is associated with a missense mutation in the paired-like homeodomain 3 (PITX3) gene. PLoS One 5:e8689, 2010. Pubmed reference: 20084168. DOI: 10.1371/journal.pone.0008689.
Williams, D.L. :
Congenital abnormalities in production animals. Vet Clin North Am Food Anim Pract 26:477-86, 2010. Pubmed reference: 21056796. DOI: 10.1016/j.cvfa.2010.09.001.
2007 Tetens, J., Ganter, M., Müller, G., Drögemüller, C. :
Linkage mapping of ovine microphthalmia to chromosome 23, the sheep orthologue of human chromosome 18. Invest Ophthalmol Vis Sci 48:3506-15, 2007. Pubmed reference: 17652717. DOI: 10.1167/iovs.07-0041.
2005 [No authors listed] :
[New test for genetically inherited blindness in sheep] Tijdschr Diergeneeskd 130:599, 2005. Pubmed reference: 16238031.
2004 Jolly, RD., Blair, HT., Johnstone, AC. :
Genetic disorders of sheep in New Zealand: a review and perspective. N Z Vet J 52:52-64, 2004. Pubmed reference: 15768097. DOI: 10.1080/00480169.2004.36405.
2003 Roe, WD., West, DM., Walshe, MT., Jolly, RD. :
Microphthalmia in Texel lambs. N Z Vet J 51:194-5, 2003. Pubmed reference: 16032324. DOI: 10.1080/00480169.2003.36364.
van der Linde-Sipman, J.S., van den Ingh, T.S., Vellema, P. :
Morphology and morphogenesis of hereditary microphthalmia in Texel sheep Journal of Comparative Pathology 128:269-75, 2003. Pubmed reference: 12834610.
1990 Jackson, E.K.M. :
Microphthalmia in Sheep Veterinary Record 126:650 only, 1990. Pubmed reference: 2382377.
1984 König, C.D. :
[Testing of rams. Microphthalmos]. Tijdschr Diergeneeskd 109:257-8, 1984. Pubmed reference: 6369625.
1980 van der Mey, GJ., Bos, H. :
[Genetics and latent defects in animals. II. Microphthalmia in sheep (author's transl)] Tijdschr Diergeneeskd 105:792-5, 1980. Pubmed reference: 7423476.
Wagenaar, G. :
[Genetics and latent defects in animals. Microphthalmia in sheep (author's transl)] Tijdschr Diergeneeskd 105:275-81, 1980. Pubmed reference: 7376170.
1978 Arndt, U., Herzog, A., Smidt, D. :
[Investigations on the optic nerves and brains of microphthalmic sheep. Communication III: report of the brain and the cortical hemispheres (author's transl)] Zuchthygiene 13:38-43, 1978. Pubmed reference: 648734.
Arndt, U., Herzog, A., Smidt, D. :
[Description of pathological-anatomical and histological findings in the brain of a sheep with congenital microphthalmia] Dtsch Tierarztl Wochenschr 85:60-1, 1978. Pubmed reference: 342224.
1961 Hanset, R. :
Hereditary microphthalmia in Texel sheep Annales de Medecine Veterinaire 105:443-449, 1961.
1958 Zwiep, I.N. :
Congenital blindness in lambs Tijdschrift voor Diergeneeskunde 83:1220-1222, 1958.

Edit History

  • Created by Frank Nicholas on 25 Feb 2010
  • Changed by Frank Nicholas on 08 Oct 2011
  • Changed by Frank Nicholas on 09 Dec 2011
  • Changed by Frank Nicholas on 25 Nov 2013
  • Changed by Frank Nicholas on 15 Mar 2019