[1] Univ Turku, Inst Biomed, Dept Med Genet, FIN-20520 Turku, Finland
[2] Univ Turku, Cent Hosp, Dept Pediat, Clin Genet Unit, FIN-20520 Turku, Finland
[3] Univ Turku, Cent Hosp, Dept Pathol, FIN-20520 Turku, Finland
[4] Natl Publ Hlth Inst, Dept Mol Med, Helsinki, Finland