Among 10 single nucleotide polymorphisms (SNPs) strongly associated with serum urate concentrations, only ABCG2 rs2231142 was associated with early-onset gout (defined as symptom onset before 40 years of age). The association was present in people in New Zealand of European and Polynesian ancestry (in the Genetics of Gout in Aotearoa study) and was confirmed in two replication cohorts. Early-onset gout was associated with an increased frequency of flares.