OGG1: A DNA repair enzyme with antimutator activity. OGG1 is one of a number of enzymes that repair damage done to DNA by environmental mutagens such as those in cigarette smoke. The gene for OGG1 is located on chromosome 3p25. Mutations in OGG1 were first reported in 1999. The OGG1 gene is polymorphic with multiple normal variations. OGG1 stands for 8-oxoguanine DNA glycosylase 1.