INTRODUCTION
Very few study addressed the relationship between Aryl-hydrocarbon receptor repressor (AHRR) DNA methylation and low birth weight, especially in multiple tissues of mother-infant pairs. In this study, we aimed to investigate AHRR DNA methylation modification in cord blood, placenta and maternal blood between full term low birth weight (FT-LBW) and full term normal birth weight (FT-NBW) newborns.
METHODS
We enrolled 90 FT-LBW and 90 FT-NBW mother-infant pairs, of which all placenta and cord blood samples were collected while 45 maternal blood samples of each group were collected. We measured AHRR DNA methylation (Chr5: 373013-373606) using Sequenom MassARRAY, and assessed associations between AHRR DNA methylation and FT-LBW using logistic regression adjusting for maternal age, education, family income, delivery mode, and passive smoking.
RESULTS
FT-LBW babies had 3% lower methylation at Chr5: 373378 (CpG 13) in cord blood, and 4-9% higher methylation levels at Chr5: 373315, 373378, 373423, 373476 and 373490/373494 (CpG 10; 13; 15; 16; 17/18 respectively) in maternal blood, comparing with FT-NBW. The methylation of Chr5: 373378 (CpG 13) remained significant association with FT-LBW both in cord blood (OR = 0.90; 95% CI: 0.82, 0.98) and maternal blood (OR = 1.14; 95% CI: 1.04, 1.25) further adjusting for each other in the same model. We observed no significant difference at any CpG sites in placenta.
DISCUSSION
AHRR DNA methylation of cord and maternal blood might be independently associated with FT-LBW in different ways.