Abnormal elongation of midpiece, absence of axoneme and outer dense fibers at principal piece level, supernumerary microtubules: a sperm defect of possible genetic origin?

We report a rare sperm tail defect, characterized by abnormal elongation of the midpiece and absence of the axoneme and the outer dense fibers at the principal piece level in 95% of flagella. This defect occurs in the vast majority of the sperm population from a sterile man, and therefore a genetic origin could be hypothesized.