Can Two Negative Parents Produce A Positive Offspring?
With Autosomal Dominant PKD, the only form of PKD so far identified and confirmed in cats, two genetic negative parents cannot produce a genetically positive offspring unless that offspring is a fresh mutation. See the discussion on autosomal-dominant inheritance below for further details. Based on all information available to date on PKD in felines, the most likely reasons for reports of a positive offspring from two negative parents are: one or both parents are “false negatives” — i.e., they are genetically positive but for one reason or another showed no signs of cysts when ultrasounded; or the offspring itself is a “false positive” — i.e., the offspring is genetically negative, but for one reason or another was diagnosed with apparent cysts when ultrasounded. See the discussion of False Negatives and False Positives for more details. Another possible explanation for a positive offspring from two negative parents is that one or both of the cats identified as a parent is really not
