An ultrastructural and immunocytochemical study of a rare genetic sperm tail defect that causes infertility in humans.
OBJECTIVE
To characterize and describe the ontogenesis of a rare flagellar defect affecting the whole sperm population of a sterile man.


METHODS
Case report.


METHODS
Regional referral center for male infertility in Siena, Italy.


METHODS
A 28-year-old man with severe asthenozoospermia.


METHODS
Physical and hormonal assays, semen analysis, and testicular biopsy.


METHODS
Semen samples and testicular biopsies were analyzed by light and transmission electron microscopy; immunocytochemical study with anti-beta-tubulin and anti-AKAP 82 antibodies was performed to detect the presence and distribution of proteins.


RESULTS
Ultrastructural analysis of ejaculated spermatozoa and testicular biopsy revealed absence of the fibrous sheath in the principal-piece region of the tail. Fibrous sheath-like structures were observed in cytoplasmic residues and residual bodies released by spermatids in the seminiferous epithelium. Other anomalies observed were supplementary axonemes and mitochondrial helix elongation. These features were confirmed by immunocytochemical staining.


CONCLUSIONS
This rare sperm tail defect, characterized by absence of the fibrous sheath, presence of supplementary axonemes, and an abnormally elongated midpiece, originates in the seminiferous tubules during spermiogenesis, as detected in testicular biopsy sections. These defects occur in the whole sperm population, and therefore a genetic origin could be suggested.
Baccetti
Baccio
B
Department of Pediatrics, Obstetrics and Reproductive Medicine, Section of Biology, University of Siena, Via T. Pendola 62, 53100 Siena, Italy.
Bruni
Emanuele
E
Gambera
Laura
L
Moretti
Elena
E
Piomboni
Paola
P
D000328:Adult; D006801:Humans; D007150:Immunohistochemistry; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology; D008297:Male; D013082:Sperm Tail / Q000473:pathology* / Q000648:ultrastructure*; D013091:Spermatogenesis / Q000235:genetics