A novel day blindness in sheep: epidemiological, behavioural, electrophysiological and histopathological studies.
Four genetically related Improved Awassi sheep flocks had sporadic births of lambs with congenital visual impairments that differed from other known forms of sheep blindness. Pedigree analysis suggested an autosomal recessive mode of inheritance. Behavioural studies of 4-month old affected lambs showed that their day vision (but not night vision) was impaired. Electrophysiological results at this age demonstrated diminished function of cones but not rods. Histopathological and immunohistochemical evaluation of affected retinas from 5-month old lambs revealed both red-green and blue cones, suggesting that the behavioural day blindness and reduced cone electroretinograms reflect cone dysfunction rather than severe cone photoreceptor loss. Awassi day blindness may be a form of achromatopsia.
Shamir
Merav H
MH
Koret School of Veterinary Medicine, The Hebrew University of Jerusalem, Rehovot 76100, Israel.
Ofri
Ron
R
Bor
Amir
A
Brenner
Ori
O
Reicher
Shay
S
Obolensky
Alexey
A
Averbukh
Edward
E
Banin
Eyal
E
Gootwine
Elisha
E
D000818:Animals; D000831:Animals, Newborn; D001766:Blindness / Q000453:epidemiology / Q000235:genetics / Q000473:pathology / Q000662:veterinary*; D004596:Electroretinography / Q000662:veterinary; D005260:Female; D007150:Immunohistochemistry / Q000662:veterinary; D008297:Male; D009154:Mutation; D010375:Pedigree; D017949:Retinal Cone Photoreceptor Cells / Q000378:metabolism / Q000473:pathology; D017948:Retinal Rod Photoreceptor Cells / Q000378:metabolism / Q000473:pathology; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000235:genetics / Q000473:pathology