Polymorphic variants on chromosomes probably play a significant role in infertility

Area of Science:

• Human Genetics
• Reproductive Biology
• Cytogenetics

Background:

• Chromosome variants, particularly in heterochromatin and nucleolar organizing regions (NOR), were historically deemed 'normal' due to lack of coding potential.
• Emerging evidence suggests genes crucial for fertility and viability may reside within heterochromatic regions.
• Recent findings indicate heterochromatic regions can be transcriptionally active under stress, challenging the 'non-coding' paradigm.

Purpose of the Study:

• To investigate the prevalence of polymorphic chromosome variants in individuals attending an In Vitro Fertilization (IVF) clinic.
• To assess the potential clinical significance of these variants in cases of primary infertility and recurrent miscarriages.
• To advocate for reconsidering the classification of chromosome variants and their screening in fertility contexts.

Main Methods:

• Karyotyping analysis was performed on 842 individuals presenting with primary infertility or recurrent miscarriages.
• Statistical analysis was used to determine the prevalence of polymorphic variants in male and female patient cohorts.
• The study correlated variant presence with reproductive history.

Main Results:

• A significant prevalence of polymorphic variants was observed: 28.82% in males and 17.19% in females attending the IVF clinic.
• These rates are considered high, suggesting a potential link between chromosome variants and reproductive issues.
• The findings challenge the traditional view of certain variants as benign, especially in the context of infertility.

Conclusions:

• Polymorphic chromosome variants are more prevalent in infertile populations than previously assumed and may not be 'normal'.
• Cytogeneticists should not overlook these variants, as they may impact fertility and pregnancy outcomes.
• Screening prospective gamete donors for chromosome variants could potentially improve IVF success rates.