Search for mutations involved in human globozoospermia*

Abstract

Globozoospermia is a severe form of teratozoospermia characterized by round-headed sperm with an absence of acrosomes. Family cases of globozoopermia suggest that this pathology has genetic origins, but the mode of inheritance remains unknown. So far, no responsible genes have been identified. Recently, a mouse lacking the casein kinase IIalpha' (encoded by the Csnk2a2 gene) was described. This mutant mouse presents a single phenotype reminiscent of that seen in human globozoospermia. Interestingly, the fission yeast orthologue (orb5) exhibits, when mutated, a spherical phenotype. Casein kinase II is a heterotetramer, composed of two catalytic subunits alpha or alpha' and two regulatory beta subunits (encoded by the Csnk2b gene). Based on the evolution conservation, phenotypes observed in mouse and yeast mutant and the structure of casein kinase II, we analysed Csnk2a2 and Csnk2b genes in six patients with globozoospermia and 10 fertile controls. Genomic DNA was extracted from peripheral blood and PCR was performed to amplify Csnk2a2 and Csnk2b genes before sequencing. No mutation was identified among these six patients. Further work is needed, with a larger patient data set, to identify putative genes involved in this form of male infertility.