Splashed White 2 (SW2)

The test determines if the PAX3 mutation (EquCab3: Chr6:11199026C>T) which causes the Splashed White 2 (SW2) phenotype is present. The inheritance is autosomal semi-dominant. SW2 originated in the Quarter Horse "Katie Gun". A horse with one copy of SW2 will usually have a wide white blaze or fully white face. All four legs will have long white socks and there can be small spots of white on the belly or lower flank. The horse may have white eyes. Many horses with the SW2 mutation are deaf. In homozygosity (SW2/SW2) it is usually embryonic lethal.