A possible haploid effect in acrosome malformations of human spermatozoa.

Acrosome malformations of spermatids and spermatozoa in the testes of two infertile patients were investigated with the light and electron microscope. The first visible abnormalities appear at early spermatid stages. The detailed morphological analysis of the malformed spermatids shows that in most cases only the differentiation of the acrosome granule is interfered with. This may be the origin of the malformations of the mature spermatozoa. The fact that almost half the early spermatids lack the acrosome granule suggests that the original cause is genetic and that the genes are expressed in the haploid phase.