Epitheliogenesis imperfecta (EI) in foals was first described in Germany in 1913.1 In this paper, the breed was not disclosed. It was later found in Ardennes foals in Sweden.2 In the 1950s, Butz and Meyer3 described EI in cold-blooded horses in Germany and provided evidence that the dermal defect was due to an autosomal recessive pattern of inheritance. The pathologic defects in dermal epithelium in the earlier reports of EI reported in horses from Europe are very similar to the disease currently affecting Belgian Draft horses and American Saddlebred horses in the United States. The first appearance of EI in American Saddlebred horses was reported to the American Saddlebred Horse Association in 1975, and since that time at least 34 verifiable cases have been reported to the association. Construction of a partial pedigree for American Saddlebreds shows a pattern of inheritance and a frequency of occurrence of EI that was consistent with an autosomal recessive inheritance pattern. It was estimated that approximately 4% of the American Saddlebred breeding population carried an allele for EI.4 A condition analogous to equine EI was first reported in Holstein-Friesian newborn calves in the United States in the 1920s.5 Several cattle breeds, including Ayrshires, Jerseys, and Shorthorns, various European breeds, and Sahiwal breeds and crosses were affected