Status of Congenineal Stationary Night Blindness in Argentine Appaloosa horses

Abstract

Congenital Stationary Night Blindness (CSNB) is a non-progressive disease of genetic origin, which seriously compromises vision under dim light conditions. It is due to alterations in the retina, specifically on the bipolar On cells that are associated with the retinal rods. This disease has been reported in different parts of the world, with Appaloosa horses being the most affected. The various theories regarding the pathophysiology of the disease agree that the "leopard complex" is involved in its development. The leopard complex (LP) comprises a group of coat patterns generated by a gene with incompletely dominance. In this breed, homozygous LP/LP and heterozygous LP/lp individuals can be phenotypically determined according to the extension of white spots. Horses that present the LP allele show alterations in the function of the Bipolar On cells associated with the rods, due to a mutation in the gene that encodes the Transient Potential Membrane Receptor 1 (TPMR1), generating an interruption in the transmission of the electrical impulse from the rods to the ganglion cells, resulting in CSNB. In the bibliographic search carried out, no scientific reports were observed that demonstrate the presence of congenital stationary night blindness in Argentina.