JLE

Médecine Thérapeutique / médecine de la reproduction

MENU

Genotype-phenotype correlations in Y chromosome long arm deletions Volume 9, issue 5, novembre-décembre 2007

Figures

See all figures

Authors
AP-HP, Hôpital Armand Trousseau, Service de Génétique et d’Embryologie médicales, Université Pierre et Marie Curie-Paris 6 EA 1533 75012 Paris, France, Institut Pasteur Unité Reproduction, Fertilité et Populations

The Y chromosome has two major roles in mammals which are sex determination in fetus and male reproduction in adults. Its sequencing in 2003 has revealed a unique structure of the long arm which contains large blocks of amplified sequences organized in palindromes and named amplicons. Recombinations between homologous sequences explain the occurrence of molecular deletions found in some infertile patients, leading to the loss of either AZFa, b or c regions. The two formers are known to be associated with azoospermia by Sertoli cell only syndrome or meiotic blockage, leading always to negative testicular biopsies, while the third one may be compatible with some degrees of spermatogenesis authorizing an ICSI in many cases. Recent data have pointed out the existence of partial deletions in AZFc, the clinical significance of which remains to be established. The most frequent of these partial deletions, the gr/gr deletion, is either considered as a polymorphism by some authors or as a predisposing factor to infertility by other. The extreme variability of Y chromosome structure among humans implies that genotype-phenotype correlations must now be established in very large cohorts of patients and normospermic controls of known geographic origins.