Paternal Age and Numerical Chromosome Abnormalities in Human Spermatozoa

Abstract

This study explores the relationship between numerical chromosome abnormalities in sperm and age in healthy men. We performed FISH in the spermatozoa of 10 donors from the general population: 5 men younger than 40 years of age and 5 fertile men older than 60 years of age. For each chromosome, 1,000 sperm nuclei were analyzed, with a total of 15,000 sperm nuclei for each donor. We used a single sperm sample per donor, thus minimizing intra-donor variability and optimizing consistent analysis. FISH with a TelVysion assay, which provides data on aneuploidy of 19 chromosomes, was used in order to gain a more genome-wide perspective of the level of aneuploidy. Aneuploidy and diploidy rates observed in the younger and older groups were compared. There were no significant differences in the incidence of autosomal disomy, sex chromosome disomy, total chromosome disomy, diploidy, nor total numerical abnormalities between younger and older men. This work confirms that aneuploidy of the sex chromosomes is more common than that of autosomes and that this does not change with age. Our results suggest that some probe combinations have a tendency to indicate higher levels of diploidy, thus potentially affecting FISH results and highlighting the limitations of FISH.