Objective  To investigate possible effects of polymorphism of key enzyme genes in the metabolic pathway of polycyclic aromatic hydrocarbons (PAHs) on the neurodevelopment among infants aged 3 years old in a birth cohort.

  Methods  We collected umbilical cord blood samples of 850 newborns delivered in 5 main general hospitals in Qingdao city of Shandong province throughout 2014. DNA were extracted from the samples and gene genotypes of key enzymes in PAHs metabolic pathway (cytochrome P450, CYP) were determined with Sequenom MassArray system. The newborns were followed-up and their neurodevelopment at 3 years old were assessed with Gesell Developmental Diagnoses Scale (GGDS)

  Results  The results of one-way analysis of variance (ANOVA) indicated that compared to the infants with minor allele homozygote (CC) or major allele heterozygote (CA), the infants with minor allele homozygote (AA) of CYP1A1 rs2606345 had significantly higher development quotient (DQ) for gross motor behavior (109.14 ± 4.38 vs. 104.99 ± 5.25 or 104.54 ± 5.55), fine motor behavior (111.00 ± 5.69 vs. 105.95 ± 5.84 or 105.6 ± 6.35), and language (106.29 ± 5.77 vs. 101.73 ± 3.61 or 101.73 ± 3.61)(P < 0.05 for all); the infants with minor allele homozygote (AA) of CYP1A1 rs4646421 had significantly higher DQ for adaptation behavior in comparison with those with major allele homozygote (CC) or heterozygote (CA)(109.37 ± 77.46 vs. 102.49 ± 4.1 or 101.86 ± 3.91)(both P < 0.05). The results also demonstrated similar correlations between neurodevelopment and gene phenotypes of CYP1A2 rs2069526 and rs2472304 and CYP1B1 rs10012, rs2617266, rs9341266, and rs10175368 among the infants.

  Conclusion  Gene polymorphisms of key enzymes in metabolic pathway of polycyclic aromatic hydrocarbons may influence neurodevelopment in 3 years old infants, which suggests that postnatal PAHs exposure might affect infant's neurodevelopment.