Correction to: European Journal of Human Genetics (2010) 18, 163–170; doi:10.1038/ejhg.2009.152; published online 7 October 2009
Since the publication of the above paper, the authors noticed that the affiliation of Umberto Balottin and Fausta Piazza is incorrect. For both the co-authors the affiliation is Child and Neuropsychiatry Unit, University of Pavia, IRCCS Fondazione C. Mondino, Pavia, Italy.
The authors would like to apologise for this mistake.
The online version of the original article can be found at 10.1038/ejhg.2009.152