Paternal Age and Numerical Chromosome Abnormalities in Human Spermatozoa

Area of Science:

• Reproductive Biology
• Human Genetics
• Cytogenetics

Background:

• Sperm aneuploidy, a numerical chromosome abnormality, can lead to infertility and developmental issues.
• The influence of paternal age on sperm chromosome abnormalities is a critical area in reproductive health research.

Purpose of the Study:

• To investigate the relationship between numerical chromosome abnormalities in sperm and age in healthy men.
• To compare aneuploidy and diploidy rates in sperm between younger (<40 years) and older (>60 years) men.

Main Methods:

• Fluorescence In Situ Hybridization (FISH) was performed on spermatozoa from 10 healthy donors (5 younger, 5 older).
• 1,000 sperm nuclei per chromosome were analyzed for each donor, totaling 15,000 nuclei per donor.
• A TelVysion assay was used to assess aneuploidy across 19 chromosomes, providing a genome-wide perspective.

Main Results:

• No significant differences were found in autosomal disomy, sex chromosome disomy, total disomy, diploidy, or total numerical abnormalities between younger and older men.
• Aneuploidy of sex chromosomes was confirmed to be more common than autosomal aneuploidy, irrespective of age.
• Certain probe combinations in FISH assays may overestimate diploidy rates, indicating potential limitations.

Conclusions:

• Paternal age does not appear to influence the rate of numerical chromosome abnormalities in sperm.
• Sex chromosome aneuploidy is consistently more prevalent than autosomal aneuploidy in sperm.
• Limitations of FISH technology, particularly regarding probe specificity for diploidy assessment, should be considered.