Human Molecular Genetics (2006) 15, 1387–1400; doi:10.1093/hmg/ddl062

This paper was inadvertently published with an incorrect affiliation for co-author Christine Métin. The correct affiliation for Christine Métin is: U616 INSERM, Hôpital Pitié-Salpétriére, 47, Bld de l'Hôpital, 75651 Paris Cédex 13, France. The authors wish to apologise for this error.