Hyperhaploid

We present three cases of PCM with hyperhaploid karyotypes from our laboratory, and review three cases reported in the literature. […] The consistent pattern of cytogenetic abnormalities present in these cases suggests that hyperhaploidy may be a distinct cytogenetic entity in PCM.

The hypohaploids may be explained in part by artifacts; however, this explanation can hardly apply to the hyperhaploids. For hyperhaploids the relative frequencies of involvement of single autosomes did not deviate significantly from expectations, assuming the same probability of nondisjunction for all autosomes.