X Chromosome Loss Tied to Infertility

Women with higher LOX levels had more than double the odds of failing to conceive naturally.

By
Mouj Hijazi
May 15, 2026
4 min

Conexiant

Overview

The study identifies a significant association between hematopoietic loss of the X chromosome (LOX) and reduced likelihood of natural conception in women, particularly those aged 35-39. A LOX threshold of 0.87% was established, indicating increased odds of infertility independent of traditional markers, suggesting a need for further investigation into its clinical implications.

Background

Understanding the factors influencing female fertility is critical, especially as age-related infertility becomes more prevalent. Traditional ovarian reserve markers may not fully capture the biological complexities of reproductive aging, such as the impact of somatic mosaicism. This study explores the potential of hematopoietic LOX as a novel biomarker for assessing fertility risk.

Data Highlights

Group	LOX Level	Odds Ratio for Infertility
Infertile Women	LOX Level > 0.87%	OR ≈ 2.2
Controls	LOX Level < 0.87%	Reference

Key Findings

Participants with infertility had higher LOX levels compared to controls, with specific values indicating a significant difference.
LOX levels increased with age, particularly in women aged 35-39, with a noted increase of X% per year.
A LOX threshold of 0.87% was identified as indicative of reduced likelihood of natural conception.
LOX was not associated with outcomes of assisted reproductive technology (ART).
LOX did not correlate with serum AMH or FSH concentrations.
LOX may reflect systemic genomic instability or biologic aging rather than traditional ovarian reserve markers.

Clinical Implications

Clinicians should consider the potential role of hematopoietic LOX as a complementary biomarker for assessing fertility risk, particularly in women of advanced reproductive age. However, reliance solely on LOX for fertility evaluation is not recommended given its modest discriminative performance, and further validation studies are necessary.

Conclusion

Hematopoietic LOX may provide valuable insights into reproductive aging and infertility risk, warranting further investigation in prospective studies to validate its clinical utility and explore its mechanisms.