Multiple congenital ocular anomalies syndrome in a family of ponys

[Guillermo Rodriguez]

Multiple congenital ocular anomalies syndrome in a family ofShetland and Deutsches Classic ponies in Belgium

Equine Veterinary Education 2012; In Press

Authors:J. E. Premont*, L. Andersson† and M. Grauwels S.
Pages:6 Pages
Language: English
Format DF
Size: 375Kb

Summary
The multiple congenital ocular anomalies (MCOA) syndrome
has been associated with the Silver phenotype only in a few
equine breeds. This report describes the phenotypic and
genotypic characteristics of MCOA in a family of Silver-coated
Shetland ponies including a 20-year-old stallion, 17-yearold
mare and their 1.5-year-old female offspring. Another
7-year-old Silver female Deutsches Classic Pony descending
from the same dam but from a different sire, was also
examined. Each pony underwent a complete ophthalmic
examination, tonometry, ocular ultrasonography and
genotyping for the silver coat colour. The stallion had a
thickened iris, temporal retinal atrophy and bilateral iridociliary
and peripheral retinal cysts. All females presented more
severe anomalies: cornea globosa, iridocorneal adhesions,
miosis, hypoplastic granula iridica and poorly responsive
pupils to light and to pharmacological mydriasis. Iris
hypoplasia, anterior cortical cataracts and temporal retinal
atrophy were detected in 2 mares. One female presented
bilateral lens subluxation. Supero-temporal cystic structures
were confirmed ultrasonographically in all ponies. The stallion
was heterozygous for the Silver mutation, whereas all females
were homozygous. This is the first report of the MCOA syndrome
in a family of Shetland ponies and a Deutsches Classic Pony in
association with the Silver phenotype, in Europe.

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