Two authors, M Halme and A Räisänen-Sokolowski, were inadvertently omitted in the paper by Harrison et al, published in December 2003 (J Med Genet 2003;40:865–71). The correct author sequence should therefore be: R E Harrison, J A Flanagan, M Sankelo, S A Abdalla, J Rowell, R D Machado, C G Elliott, I M Robbins, H Olschewski, V McLaughlin, E Gruenig, F Kermeen, M Halme, A Räisänen-Sokolowski, T Laitinen, N W Morrell, R C Trembath. The error is much regretted.