Leopard complex causes a number of different spotting patterns
Breeds known to carry this mutation
Appaloosas, Knabstruppers and some pony breeds
Incomplete dominant. A single copy is enough to allow expression of a spotting pattern but two copies will often increase the amount of white observed.
Leopard Complex causes a number of different spotting patterns. Mottled skin around the muzzle, eyes, coronets (causing striped hooves), genitalia and anus is also characteristic. There may be progressive roaning (varnishing) of the coat with age and the horse may also have distinct spots of colour on a white background on part or all of their body. Some of the wide range of Appaloosa patterns are caused by the PATN gene working with LP. Horses homozygous for LP (LP/LP) are night blind and are unable to see in low or no light situations.
Interpretation of results
n/n: Horse does not carry the mutation that causes leopard complex (Appaloosa) spotting.
Lp/n: Horse carries one copy of the mutation that causes leopard complex (Appaloosa) spotting.
Lp/Lp: Horse carries two copies of the mutation that causes leopard complex (Appaloosa) spotting. This horse will be night blind and will pass on the Lp variant to all of its offspring.
Bellone et al. Evidence for a Retroviral Insertion in TRPM1 as the Cause of Congenital Stationary Night Blindness and Leopard Complex Spotting in the Horse. 2013 PLoS ONE; 8:e78280. doi: 10.1371/journal.pone.0078280