Abstract
Delta aminolevulinic acid dehydratase (ALAD) gene polymorphisms (rs1139488 - MspI and RsaI in exon 4) and Matrix Gla (g-carboxyglutamic acid) protein T-138C polymorphisms were reported to affect the response of individuals to lead toxicity symptoms. In several previous studies, large inter-ethnic differences in the frequencies of different gene variants have been reported. However, no informational data about the Arab world has been documented. This study was carried out to examine the effects of ALAD and MGP gene polymorphisms on blood lead levels. Method: A total of 127 subjects employed in different professions like battery shops, painting industry and automobile repair shop and plumbers from different parts of Riyadh region, Saudi Arabia. Blood lead levels (BLL), and genotyping, and restriction digestion was performed for each sample. Result: The BLLs in low BLL (<10 mu g/dL) group remained well within prescribed safe limits with mean levels of 4.37 mu g/dL. In high BLL (> 10 mu g/dL) group however, the levels were significantly elevated to 18.12 mu g/dL (p<0.001). Workers involved in battery acidifying area were found to have high blood lead level (18.70 mu g/dL), followed by those involved in plate making process (12.57 mu g/dL) and opening and breaking of old batteries (10.77 mu g/dL). On the other hand, lead level was found to be as low as <3.3 mu g/dL among the workers who were not involved in battery breaking or manufacturing process (administration, drivers and security personnel). Overall, the genotype frequencies of GG and GC+CC for ALAD exon 4 MspI restriction site (G177C) were 96.7% and 3.3%, with allele frequencies of 0.979 (G) and 0.01 (C), respectively. For ALAD exon 4 RsaI restriction site (T168C), the frequency of TT and TC+CC genotypes were 65% and 35% with allele frequency of 0.779 (T) and 0.220 (C) respectively. For the Matrix Gla (gamma-carboxyglutamic acid) gene (MGP) T-138C polymorphism, the variants TC and CC were not detected in this population; all subjects had TT genotype. BLLs for ALAD G177G, ALAD C168C and MGP T-138T genotypes from High BLL group were 18.70, 19.09 and 15.05 mu g/dl respectively. (C) 2018 The Authors. Published by IASE.