The SD2 phenotype is characterized by short legs with normal body length and width. In most cases the forelegs are slightly more affected than the hind legs. The international breed standard calls for shoulder heights of 56 cm?57 cm in male and 54 cm?56 cm in female Labrador Retrievers, respectively. The shoulder height in affected animals is reduced by ~6 cm on average. However, it must be noted that shoulder height is only an imperfect proxy for the SD2 phenotype as shoulder height is a complex trait with significant variance due to genetic and environmental factors. According to breeders' reports SD2-affected dogs are not particurlarly prone to secondary joint degeneration or any other health problems apart from the disproportionate dwarfism. Skeletal dysplasia 2 (SD2) is a mild form of disproportionate dwarfism in Labrador Retrievers. Affected dogs have short legs and their shoulder height is reduced by ~6 cm compared to non-affected dogs. (From OMIA)