The changes below were made to the article on the date noted. These changes have been incorporated in the article and the details are documented here.

20 November 2011:

In Appendix 1 there are two typographical errors. For marker rs7543472 the alleles should be T (common allele and risk allele) and C (rare allele and non-risk allele) instead of T and G as shown. For Marker rs11260867 the alleles have been switched and should be C (common allele and risk allele) and G (rare allele and non-risk allele). The p-values and odds ratios for each marker remain unchanged.