Effect of the delta-aminolevulinic acid dehydratase gene polymorphism on renal and neurobehavioral function in workers exposed to lead in China

摘要

Effects of delta-aminolevulinic acid dehydratase (ALAD) polymorphisms on the renal and neurobehavioral functions were investigated in Chinese workers from a storage battery plant exposed to inorganic lead. Blood and urine were collected from each worker to determine the ALAD genotypes, blood lead levels (PbB), urinary P2-MG and urinary NAG activity. The World Health Organization Neurobehavioral Core Test Battery (WHO-NCTB) was used. Of the 135 lead workers tested for ALAD genotype, 126 were ALAD1-1,9 were ALAD1-2 but none were ALAD2-2. The gene frequencies of ALADI-1 and ALADI-2 were 93.33% and 6.67%, respectively. The workers with ALAD1-2 genotype had significantly higher concentrations of PbB (62.52 μg/dl vs. 41.02 μg/dl), urinary NAG (22.01 U/gCr vs. 13.49 U/gCr), urinary β2-MG (194.98 μg/gCr vs. 112.88 μg/gCr), and digit span backward (DSB) score (6.67 vs. 533) than those of ALADI-1 genotype. Urinary NAG of ALADI-2 genotype carriers was significantly higher than that of ALADI-1 genotype under the same blood lead level (b, 0.75 vs. b, 0.29). Interaction between PbB and ALAD genotypes has a significant influence on NAG (P=0.02) and β_2-MG (P= 0.01). It is postulated that the workers with the ALAD2 allele appear to be more susceptible to the effects of lead on renal injury, whereas neurobehavioral functions in ALAD1 homozygote tend to be more vulnerable.