Nat. Genet. 36, 837–841 (2004).

On page 837, in the right column, the first full sentence should begin, “The G variant of this SNP had a higher frequency in affected individuals from the US (62.7%) than in matched controls (52.4%; P = 0.0008)...”

In Figure 2, the arrow indicating the direction of transcription of SUMO4 should be pointing to the right.

The version of Supplementary Table 1 that initially appeared online was incorrect and has been replaced with the correct version.