Association between delta-aminolevulinic acid dehydratase polymorphism and placental lead levels

• Maternal ALAD G177C polymorphism was associated with placental lead levels.
• Mothers with ALAD2 allele had higher placental lead levels than those with ALAD1 allele.
• Mothers with ALAD1 allele may be more advantageous in terms of having lower placental lead levels.

Lead inhibits the delta-aminolevulinic acid dehydratase (ALAD) activity and results in neurotoxic aminolevulinic acid accumulation in the blood. During pregnancy, lead in the maternal blood can easily cross the placenta. The aim of this study was to determine whether the maternal ALAD G177C polymorphism (rs1800435) was related to the placental lead levels. The study population comprised 97 blood samples taken from mothers to investigate ALAD G177C polymorphism and their placentas to measure lead levels. ALAD G177C polymorphism was detected by standard polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) technique and atomic absorption spectrometry (AAS) equipped with a graphite furnace and Zeeman background correction system was used for lead determination. The median placental lead levels for ALAD1-1, ALAD1-2 and ALAD2-2 genotypes were 7.54 μg/kg, 11.78 μg/kg and 18.53 μg/kg, respectively. Statistically significant association was found between the maternal ALAD G177C polymorphism and placental lead levels (p < 0.05). This study suggested that maternal ALAD G177C polymorphism was associated with placental lead levels.