Correction to: European Journal of Human Genetics (2012) 20, 778–782; doi:10.1038/ejhg.2011.254; published online 11 January 2012

Since the publication of this article, the authors have noticed that they had omitted elements from the Acknowledgement section. This has now been rectified and the corrected article appears in this issue. The html and online PDF versions have also been rectified.

The authors would like to apologise for their error.