Association between aminolevulinate dehydrogenase genotype and blood lead levels in Taiwan

This study was designed to evaluate the association between the aminolevuli nate dehyrdrogenase (ALAD) genotype and blood lend levels in a general popu lation environmentally exposed to lend. This study population of 660 subjec ts was secondarily sampled from the 3000 random samples of Taiwanese genera l population to study the distribution of blood lead levels in the Taiwanes e population. A simple assay based on the polymerase chain reaction-restric tion fragment length polymorphism technique was used to determine the genot ype of the ALAD gene, This study found that most of the Taiwanese populatio n was ALAD 1-1 (95.4%). Only 4.6% (30 subjects) of population were found to be 1-2 or 2-2, It has been hypothesized that the ALAD2 allele is associate d with increased absorption of lead. This study found that individuals with ALAD2 alleles had 20% higher blood lead levels than persons with ALAD1 all eles (7.83 +/- 5.95 vs 6.51 +/- 5.03 mu g/dL). However, the difference was not statistically significant, even after adjustment for other risk factors of environmental exposure. The result supports the previous finding that i ndividuals with ALAD2 allele had higher blood lead levels. The small sample size and large amount of variation in our study may account for the insign ificant association.