Congenital ocular anomalies in purebred and crossbred Rocky and Kentucky Mountain horses in Canada.
Abstract: Multiple congenital ocular anomalies in purebred and crossbred Rocky and Kentucky Mountain horses in Canada are frequently diagnosed with biomicroscopic and indirect ophthalmoscopic examination. In order of frequency detected, these include temporal ciliary epithelial cysts; iridal hypoplasia; prominent corneas; focal temporal retinal degeneration related to ciliary cysts; and, rarely, retinal detachment. A pedigree analysis confirms a dominant mode of inheritance with incomplete penetrance and with a linkage to coat color. Des anomalies oculaires congénitales multiples chez des chevaux Rocky et Kentucky Mountain de race pure et croisée au Canada sont souvent diagnostiquées par examens biomicroscopiques et ophtalmoscopiques indirects. Par ordre de fréquence, les anomalies détectées comprennent les kystes épithéliaux ciliaires temporaux, l’hypoplasie iridienne, la cornée proéminente, la dégénération focale de la rétine temporale reliée aux kystes ciliaires et, rarement, le détachement de la rétine. Une analyse du pedigree confirme un mode dominant de transmission génétique avec pénétrance incomplète et liaison à la couleur de la robe. (Traduit par Docteur André Blouin)
Publication Date: 2008-10-02 PubMed ID: 18827844PubMed Central: PMC2430397
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- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This study explores various types of congenital ocular anomalies common in purebred and crossbred Rocky and Kentucky Mountain horses in Canada diagnosed through biomicroscopic and indirect ophthalmoscopic examination. The study further confirms that these eye abnormalities are hereditary, with their transmission linked to coat color.
Research Objectives and Methods
- The research aimed to identify, diagnose, and understand the frequency of various congenital ocular anomalies (inherited eye diseases) in purebred and crossbred Rocky and Kentucky Mountain horses in Canada.
- The researchers used biomicroscopic and indirect ophthalmoscopic examination as primary diagnostic tools. These methods facilitate a non-invasive, in-depth examination of the horse’s eye structure to identify any abnormalities.
Findings
- The study discovered several eye anomalies, including temporal ciliary epithelial cysts (noncancerous growths on the ciliary body responsible for producing eye fluid), iridal hypoplasia (underdevelopment of the iris), prominent corneas, focal temporal retinal degeneration related to ciliary cysts, and on rare occasions, retinal detachment (when the retina pulls away from its normal position).
- These anomalies were listed in order of detection frequency, beginning with the most commonly observed condition to the least common.
Analysis of Anomalies
- The research performed a pedigree analysis following detection and identification of these anomalies, aiming to understand the genetic pattern behind their occurrence.
- This analysis confirmed a dominant mode of inheritance, implying that these conditions are largely passed on to offspring from an affected parent. It also indicated that the transmission is characterized by incomplete penetrance. In genetics, this refers to the phenomenon whereby not all individuals carrying a mutant gene express the trait.
- The study revealed that the genetic transmission of these conditions is linked to coat color, although it doesn’t elaborate on the nature of this relationship.
Cite This Article
APA
Grahn BH, Pinard C, Archer S, Bellone R, Forsyth G, Sandmeyer LS.
(2008).
Congenital ocular anomalies in purebred and crossbred Rocky and Kentucky Mountain horses in Canada.
Can Vet J, 49(7), 675-681.
Publication
Researcher Affiliations
- Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, 52 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B4. bruce.grahn@usask.ca
MeSH Terms
- Animals
- Breeding
- Canada
- Eye Abnormalities / genetics
- Eye Abnormalities / veterinary
- Female
- Genes, Dominant
- Genetic Linkage
- Genetic Predisposition to Disease
- Hair Color / genetics
- Horse Diseases / congenital
- Horse Diseases / genetics
- Horses
- Male
- Pedigree
- Phenotype
References
This article includes 21 references
- Ramsey DT, Ewart SL, Render JA, Cook CS, Latimer CA. Congenital ocular abnormalities of Rocky Mountain Horses.. Vet Ophthalmol 1999;2(1):47-59.
- Ramsey DT, Hauptman JG, Petersen-Jones SM. Corneal thickness, intraocular pressure, and optical corneal diameter in Rocky Mountain Horses with cornea globosa or clinically normal corneas.. Am J Vet Res 1999 Oct;60(10):1317-21.
- Ewart SL, Ramsey DT, Xu J, Meyers D. The horse homolog of congenital aniridia conforms to codominant inheritance.. J Hered 2000 Mar-Apr;91(2):93-8.
- Bedford PGC. Diseases and surgery of the canine eyelid.. .
- Brunberg E, Andersson L, Cothran G, Sandberg K, Mikko S, Lindgren G. A missense mutation in PMEL17 is associated with the Silver coat color in the horse.. BMC Genet 2006 Oct 9;7:46.
- Reissmann M, Bierwolf J, Brockmann GA. Two SNPs in the SILV gene are associated with silver coat colour in ponies.. Anim Genet 2007 Feb;38(1):1-6.
- Götz W. Transgenic models for eye malformations.. Ophthalmic Genet 1995 Sep;16(3):85-104.
- Yang LL, Lambert SR. Peters' anomaly. A synopsis of surgical management and visual outcome.. Ophthalmol Clin North Am 2001 Sep;14(3):467-77.
- Alward WL. Axenfeld-Rieger syndrome in the age of molecular genetics.. Am J Ophthalmol 2000 Jul;130(1):107-15.
- Lines MA, Kozlowski K, Walter MA. Molecular genetics of Axenfeld-Rieger malformations.. Hum Mol Genet 2002 May 15;11(10):1177-84.
- Williams DL. A comparative approach to anterior segment dysgenesis.. Eye (Lond) 1993;7 ( Pt 5):607-16.
- Churchill A, Booth A. Genetics of aniridia and anterior segment dysgenesis.. Br J Ophthalmol 1996 Jul;80(7):669-73.
- Irby NL, Aguirre GD. Congenital aniridia in a pony.. J Am Vet Med Assoc 1985 Feb 1;186(3):281-3.
- Peiffer RL Jr, Belkin PV. Keratolenticular dysgenesis in a kitten.. J Am Vet Med Assoc 1983 Jun 1;182(11):1242-3.
- Rebhum WC. Congenital anterior staphyloma with rudimentary lens in a calf.. J Am Vet Med Assoc 1977 Sep 1;171(5):440-2.
- Lewis D, Kelly D, Sansom J. Congenital microphthalmia and other developmental ocular anomalies in the Doberman.. J Small Anim Pract 1986;27:559–566.
- Halenda RM, Grahn BH, Sorden SD, Collier LL. Equine congenital glaucoma: Clinical and light microscopic findings in two cases.. J Vet Comp Ophthalmol 1997;7:105–109.
- Cullen CL, Grahn BH. Congenital glaucoma in a llama (Llama glama). J Vet Comp Ophthalmol 1997;7:253–257.
- Reneker LW, Silversides DW, Xu L, Overbeek PA. Formation of corneal endothelium is essential for anterior segment development - a transgenic mouse model of anterior segment dysgenesis.. Development 2000 Feb;127(3):533-42.
- Cook CS. Ocular embryology and congenital malformations.. .
- van Heyningen V. Developmental eye disease--a genome era paradigm.. Clin Genet 1998 Oct;54(4):272-82.
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