Allele C of rs2237892 in the maternally expressed gene KCNQ1 was first observed to associated with T2D in Asian populations11, 12. Power to detect association in populations of European ancestry is low due to the high frequency of the variant there (~93% compared to ~61% in Asians), but the association has nonetheless been replicated11, 12. In the T2D samples we have previously employed in genome-scans (Table 1) that include 1,468 cases, none of the tests involving parental origin were significant for rs2237892. But when a new T2D list (Supplementary Information) allowed us to add 783 patients, giving a total of 2,251 cases, allele C was significantly associated with the disease (OR = 1.30, P = 0.0084) when maternally transmitted, while the results for the paternally inherited allele were flat (OR = 1.03, P = 0.71).
