Evaluating LINE-1 methylation in cleft lip tissues and its association with early pregnancy exposures.

AIM: To pilot investigation of methylation of long interspersed nucleotide element-1 in lip tissues from infants with nonsyndromic cleft lip, and its association with maternal periconceptional exposures.

METHODS

The lateral and medial sides of the cleft lips of 23 affected infants were analyzed for long interspersed nucleotide element-1 methylation by bisulfite conversion and pyrosequencing.

RESULTS

The medial side showed 1.8% higher methylation compared with the lateral side; p = 0.031, particularly in male infants (2.7% difference; p = 0.011) or when the mothers did not take folic acid during periconceptional period (2.4% difference; p = 0.011). These results were not statistically significant when Bonferroni adjustment was used.

CONCLUSION

The observed differences in DNA methylation, although nonsignificant after correction for multiple comparisons, suggest that differential regulation of the two sides may impact lip fusion and warrant larger-scale replication.