Comet assay–based risk prediction of cleft lip and palate during preconception planning in women residing in areas with environmental toxicants

Relevance. The alkaline comet assay is among the most sensitive methods for detecting genotoxic effects in diverse tissues and body fluids. It quantifies the migration of fragmented chromosomal DNA in an electric field; the extent of migration correlates with the degree of DNA damage.

Materials and methods. The study was conducted at the Republican Children’s Clinical Hospital (Ufa, Russian Federation). Five groups were compared: (1) 40 children with cleft lip and palate (CLP) living in an area without environmental toxicants; (2) 60 children with CLP living in an area with environmental toxicants; (3) 40 mothers residing in an area without environmental toxicants; (4) 60 mothers residing in an area with environmental toxicants; and (5) 40 apparently healthy children to establish reference values. Peripheral blood lymphocytes were evaluated using the alkaline comet assay. Gels were stained with SYBR Green I. Statistical analyses were performed in R (version 4.x) using the stats package.

Results. Among children with CLP residing in areas with environmental toxicants, the mean tail length measured 11.473 µm (95% CI, 11.411–11.535), % tail DNA averaged 7.816 (95% CI, 7.768–7.865), and the tail moment amounted to 0.897 (95% CI, 0.886–0.907). In mothers from the same areas, the mean tail length reached 11.403 µm (95% CI, 11.336–11.470), % tail DNA averaged 6.662 (95% CI, 6.628–6.697), and the tail moment was estimated at 0.760 (95% CI, 0.754–0.766).

Conclusion. Use of the alkaline comet assay during preconception planning in women residing in regions with environmental toxicant contamination provides significant clinical utility for risk prediction of CLP in offspring. Thresholds of tail length ≥ 11.0 µm, % tail DNA ≥ 6.5, and tail moment ≥ 0.73 are associated with a markedly increased predicted risk of cleft lip and palate in the offspring.  

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