Progressive Retinal Atrophy
Early Symptoms to Look For
Progressive Retinal Atrophy is inherited as an autosomal recessive trait in nearly all breeds. There is a great discrepancy between genotype and phenotype for PRA. Note that the PRA gene is denoted by the letter p. A Basenji with homozygous dominant alleles (PP) is not a carrier of the disease and does not display signs of it. A heterozygous genotype (Pp) is a carrier of the disease yet is unaffected by it. A homozygous recessive (pp) dog is both a carrier of the disease and affected by it. Two heterozygous parent Basenjis have a 1 in 4 chance of having a puppy that will suffer PRA.
In the video below, the speaker explains these genotypes and phenotypes in dogs (from 8:21 to 9:10).
Basenji breeders were once cautious when it came to the spread of PRA. A dog that was even slightly suspected of being a carrier was not bred. However, the standards of breeders have gone downhill in recent years, and carelessness has led to a rise in PRA carriers and affected dogs.
The ability to DNA test a dog for the genes related to PRA makes the eradication of this disease more feasible for breeders today by taking out the guesswork.
"Diagnostic Ophthalmology" by Bruce H. Grahn and Lynne S. Sandmeyer
"Progressive Retinal Atrophy in the Border Collie: A new XLPRA" by T. Vilboux, G. Chaudieu, P. Jeannin, D. Delattre, B. Hedan, C. Bourgain, G. Queney, F. Galibert, A. Thomas, and C. André.
"Basenji Health Information" on Basenji Club of America website