RESUMEN
<p><b>OBJECTIVE</b>To investigate the polymorphism of delta-aminolevulinic acid dehydratase(ALAD) and the genetic susceptibility to lead toxicity in Uighur and Yi population in China.</p><p><b>METHODS</b>The ALAD genotypes were determined by PCR and MspI restriction fragment length polymorphism techniques in 214 Uighur individuals from Xinjiang autonomous region and 144 Yi individuals from Yunnan province. The correlation between the polymorphism of ALAD and blood lead levels, and the factors affecting the latter were explored.</p><p><b>RESULTS</b>The frequencies of the allele ALAD1 and ALAD2 in Uighur are 0.91 and 0.09; and in Yi are 0.98 and 0.02 respectively. In Uighur the average blood lead level was (76 +/- 4) microgram/L, and 25.7% individuals with blood lead level > or = 100 micrograms/L. In Yi the average blood lead level was (50 +/- 16) microgram/L, and 6.3% individuals with blood lead level > or = 100 micrograms/L. However, no statistic correlation between the distribution of ALAD alleles and the blood lead level was found in both populations.</p><p><b>CONCLUSION</b>The genetic susceptibility of ALAD polymorphism to lead toxicity may exhibit in a lead dose-dependent manner.</p>