Direct duplication of the Y chromosome with normal phenotype - incidental finding in two cases.

Structural rearrangement in the Y chromosome is closely involved in spermatogenesis. However, several Y chromosome variants may have no deleterious effects on male reproduction. Here, we report two cases of Y chromosomal duplication from incidental findings. Their FISH analysis revealed direct duplication of large segments of short and long arms of the Y chromosome. Nearly two intact Y chromosomes were carried in these two cases with normal phenotype.