Aussie Genetics Fact Sheet: Pelger-Huet Anomaly (PHA) by C.A. Sharp Pelger-Huet Anomaly is an incomplete dominant. Dogs with only one gene are almost always healthy, but if bred to another heterozygote, the pups that receive two PHA genes will be reabsorbed, stillborn or die shortly after birth. PHA isa breeder's problem, rather than an owner's, because it rarely affects the health of a dog but results in small litters or loss of neonates. There is a blood test to screen for it (make sure the lab does the canine test, not one for another species because they don't work for dogs). All Aussies used for breeding whose parents have not tested clear of PHA should be screened. If a dog carries PHA, don't ever breed it to another carrier. Be sure anyone buying puppies of a PHA carrier for breeding knows that they will need to be screened to determine their PHA status before being bred.