Hum. Reprod. Advance Access originally published online on January 5, 2007
Human Reproduction 2007 22(4):1052-1059; doi:10.1093/humrep/del481
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Ultrastructural nuclear defects and increased chromosome aneuploidies in spermatozoa with elongated heads
1 Department of Genetic and Reproduction, APHP, INSERM U782, Paris 11 University, Antoine Béclère Hospital, Clamart, France 2 Department of Andrology 3 Department of Hormonology and Molecular Biology, APHP, Kremlin Bicêtre Hospital, Kremlin Bicêtre, France
4 To whom correspondence should be addressed at: Unité d'Andrologie, APHP, INSERM U782, Service de Biologie et Génétique de la Reproduction, Hôpital du Kremlin Bicêtre, 63 rue Gabriel Peri, 94276 Le Kremlin Bicêtre, France. Tel.: +33 1 45 21 26 44; Fax: +33 1 45 21 23 21; E-mail: nprisant{at}yahoo.com
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% (3075 versus 02% 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.
Key words: chromosome abnormalities/electron microscopy/elongated sperm head/fluorescence in-situ hybridization/male infertility
Submitted on July 27, 2006; resubmitted on October 5, 2006; accepted on November 29, 2006.