Objective: To explore the associations of polymorphism of delta-aminolevulinic acid dehydratase (ALAD) gene with blood levels of lead and zinc protoporphyrin (ZPP).
Methods: Blood samples were collected from 370 children exposed to a higher level environmental lead and their blood levels of lead and ZPP, and ALAD genotype were examined. Exposure to lead condition, such as parents' lead exposure and sites of lead source around their residence, and age and sex were matched in ALAD1-1 and ALAD1-2/2-2 subgroups.
Results: Blood lead level was higher in the ALAD1-2/2-2 subgroup than that in the ALAD1-1 children [(2.621 +/- 0.561) mumol/L vs (2.360 +/- 0.596) mumol/L, P = 0.04)]. Blood ZPP level was also higher in with ALAD1-2/2-2 subgroup than that in the ALAD1-1 genotype [(13.07 +/- 9.38) mumol/L vs (9.90 +/- 6.30) mumol/L), P = 0.02)].
Conclusion: The results suggest that the ALAD1-2/2-2 genotype may influence the body burden and blood toxicity of lead in high lead exposed children.