Previously, we showed that As exposure in this population is associated with increase in mRNA levels of an oxidative-response DNA repair gene, OGG1 (8-oxoguanine DNA glycosylase gene; GenBank accession no. AB000410.1), and a nucleotide excision repair gene, ERCC1 (excision repair cross-complementing rodent repair deficiency, complementation group 1; GenBank accession no. BC008930) (Mo et al. 2006; Mo J, unpublished data). This evidence concerns the gene OGG1 and hyperinsulinemic hypoglycemia, familial, 4.