The defect must be of a true genetic nature and not environmentally induced in any way. (dogplay.com)
It is most often of genetic nature, but may also occur because of eye, nerve, or brain damage, or due to exposure to certain chemicals. (sciencedaily.com)
Since the 1950s, there has been a growing nearly - worldwide awareness of the genetic nature of HD (hip dysplasia, often called CHD — canine HD — by vets in order to distinguish it from HD in man and other species, although very little difference exists). (siriusdog.com)