Ultrastructural nuclear defects and increased chromosome aneuploidies in spermatozoa with elongated heads.
BACKGROUND
Cellular and molecular mechanisms leading to elongated sperm heads are not known. We have analysed the nuclear status of spermatozoa with elongated heads.


METHODS
Fourteen men with at least 30% of spermatozoa with an elongated nucleus were studied and compared with five fertile men as controls. Sperm morphology was analysed by a quantitative ultrastructural analysis. Sperm chromosomal content was assessed by three-colour fluorescence in-situ hybridization (chromosomes X, Y, 18). Y chromosome microdeletion and karyotype were analysed.


RESULTS
Elongated sperm head rates of the patients were 46.9% (30-75 versus 0-2% in the control group) by light microscopy and 34.4% by electron microscopy. In all patients, the chromatin was poorly condensed in elongated sperm heads (50% of elongated nuclei). No anomalies of sperm biochemical markers were found. All the men showed normal karyotype (46,XY) and absence of Y chromosome microdeletion. Aneuploidy rates of gonosomes and chromosome 18 were significantly increased in patients (1.64- and 3.6-fold, P = 0.006 and 0.026, respectively).


CONCLUSIONS
This study demonstrates that impaired chromatin compaction and slightly increased chromosome aneuploidies are found in spermatozoa with an elongated head, suggesting possible mechanisms such as meiotic non-disjunctions or spermiogenesis anomalies.
Prisant
N
N
Department of Genetic and Reproduction, APHP, INSERM U782, Paris 11 University, Antoine Béclère Hospital, Clamart, France. nprisant@yahoo.com
Escalier
D
D
Soufir
J-C
JC
Morillon
M
M
Schoevaert
D
D
Misrahi
M
M
Tachdjian
G
G
D000782:Aneuploidy; D002467:Cell Nucleus / Q000648:ultrastructure*; D002470:Cell Survival; D002869:Chromosome Aberrations; D002875:Chromosomes / Q000648:ultrastructure*; D017353:Gene Deletion; D006801:Humans; D017403:In Situ Hybridization; D017404:In Situ Hybridization, Fluorescence; D007248:Infertility, Male / Q000175:diagnosis* / Q000235:genetics* / Q000628:therapy; D007621:Karyotyping; D008297:Male; D008854:Microscopy, Electron; D012730:Sex Chromosomes; D013094:Spermatozoa / Q000473:pathology* / Q000648:ultrastructure