Abnormal elongation of midpiece, absence of axoneme and outer dense fibers at principal piece level, supernumerary microtubules: a sperm defect of possible genetic origin?
OBJECTIVE
To characterize a flagellar defect involving 95% of the sperm population from an infertile man.


METHODS
Case report.


METHODS
Interdepartmental Centre for Research and Therapy of Male Infertility, Siena, Italy.


METHODS
A 42-year-old infertile man with severe asthenozoospermia.


METHODS
Family history, physical examination, hormonal analysis, microbial assays, semen analysis, transmission electron microscopy (TEM) and scanning electron microscopy (SEM), tubulin distribution investigated by immunocytochemistry, fluorescence in situ hybridization for chromosomes 18, X, and Y.


METHODS
Ultrastructural abnormalities of the flagellum detected by methods listed.


RESULTS
Ultrastructural analysis revealed, in 95% of sperm cells, the total absence of the axoneme and outer dense fibers at the principal piece level, whereas the midpiece appeared abnormally long. Tubulin localization showed a total disorganization of the axoneme with a network of microtubular structures emerging randomly at any level of the flagellum. Fluorescence in situ hybridization analysis was normal.


CONCLUSIONS
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.
Moretti
Elena
E
Department of Surgery, Biology Section, University of Siena, Interdepartmental Centre for Research and Therapy of Male Infertility, Siena, Italy.
Pascarelli
Nicola Antonio
NA
Federico
Maria Grazia
MG
Renieri
Tommaso
T
Collodel
Giulia
G
D000328:Adult; D053627:Asthenozoospermia / Q000175:diagnosis* / Q000235:genetics*; D054468:Axoneme / Q000235:genetics* / Q000473:pathology; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008297:Male; D008870:Microtubules / Q000473:pathology*; D013094:Spermatozoa / Q000473:pathology*