Complete or partial loss of the Y chromosome in an unselected cohort of 865 non-vasectomized, azoospermic men

BackgroundStructural abnormalities as well as minor variations of the Y chromosome may cause disorders of sex differentiation or, more frequently, azoospermia. This study aimed to determine the prevalence of loss of Y chromosome material within the spectrum ranging from small microdeletions in the azoospermia factor region (AZF) to complete loss of the Y chromosome in azoospermic men.ResultsEleven of 865 azoospermic men (1.3%) collected from 1997 to 2022 were found to have a karyotype including a 45,X cell line. Two had a pure 45,X karyotype and nine had a 45,X/46,XY mosaic karyotype. The AZF region, or part of it, was deleted in eight of the nine men with a structural abnormal Y-chromosome. Seven men had a karyotype with a structural abnormal Y chromosome in a non-mosaic form. In addition, Y chromosome microdeletions were found in 34 men with a structural normal Y chromosome. No congenital malformations were detected by echocardiography and ultrasonography of the kidneys of the 11 men with a 45,X mosaic or non-mosaic cell line.ConclusionsIn men with azoospermia, Y chromosome loss ranging from small microdeletions to complete loss of the Y chromosome was found in 6.1% (53/865). Partial AZFb microdeletions may give a milder testicular phenotype compared to complete AZFb microdeletions. ContexteDes anomalies structurelles ainsi que des variations mineures du chromosome Y peuvent provoquer des troubles de la differenciation sexuelle ou, plus frequemment, une azoospermie. Cette etude visait a determiner la prevalence de la perte de materiel chromosomique Y dans le spectre allant de petites microdeletions dans la region du facteur d'azoospermie (AZF) a la perte complete du chromosome Y chez les hommes azoospermiques.ResultatsOnze des 865 hommes azoospermiques (1,3 %), collectes entre 1997 et 2022, presentaient un caryotype comprenant une lignee cellulaire 45,X. Deux avaient un caryotype pur 45,X et neuf avaient un caryotype mosaique 45,X/46,XY. La region AZF, ou une partie de celle-ci, etait absente chez huit des neuf hommes presentant un chromosome Y anormal sur le plan structurel. Sept hommes presentaient un caryotype avec un chromosome Y structurellement anormal sous une forme non mosaique. De plus, des microdeletions du chromosome Y ont ete trouvees chez 34 hommes presentant un chromosome Y de structure normale. Aucune malformation congenitale n'a ete detectee par echocardiographie et echographie des reins des 11 hommes porteurs d'une lignee cellulaire 45,X mosaique ou non mosaique.ConclusionsChez les hommes qui ont une azoospermie, une perte du chromosome Y, allant de petites microdeletions a une perte complete du chromosome Y, a ete observee chez 6,1 % (53/865). Les microdeletions partielles de la region AZFb peuvent donner un phenotype testiculaire plus doux que les microdeletions completes de l'AZFb.

Automated summary

This study aimed to determine the prevalence of loss of Y chromosome material within the spectrum ranging from small microdeletions to complete loss of the Y chromosome in azoospermic men. The results showed that Y chromosome loss ranging from small microdeletions to complete loss of the Y chromosome was found in 6.1% of azoospermic men. Partial AZFb microdeletions may give a milder testicular phenotype compared to complete AZFb microdeletions.