Association of Delta-Aminolevulinic Acid Dehydratase Polymorphism with Blood Lead and Hemoglobin Level in Lead Exposed Workers

Introduction: Despite decades of intensive research, lead toxicity still remains one of the most health concerns. Hence, risks posed by lead are more likely to be determined by individual susceptibility as delta-aminolevulinic acid dehydratase (ALAD) gene can modify lead toxicokinetics.

Method: The present study was aimed to evaluate the association of ALAD gene polymorphism (rs1800435 C/G) (ALAD 1-1, ALAD 1-2, ALAD 2-2) with blood lead level (BLL) and hemoglobin (Hb) content from 200 lead-exposed workers of Gujarat, India against 200 controls.

Results: ALAD genotype frequency was found to be 90%, 8% and 2% in control whereas 80%, 14.5% and 5.5% in workers for ALAD 1-1, 1-2 and 2-2 genotypes, respectively. ALAD 1-1 genotype was attributed to higher BLL and lower Hb content as compared to ALAD 1-2/2-2 genotype in workers. Whereas, inverse association had been observed between BLL and Hb content in workers having ALAD 1-1 genotype. On the other hand, ALAD 1-2/2-2 genotype might play an important role in lead toxicity by decreasing free lead in blood and by transporting into tissues due to more binding affinity. So, it may protect Hb against free lead by decreasing lead availability in blood.

Conclusion: To deal with lead toxicity more effectively, attention should be given to the workers having the ALAD 1-1 genotype.