[1] Inst Mother & Child Hlth, Warsaw, Poland
[2] Katholieke Univ Leuven, Dept Human Genet, Leuven, Belgium
[3] Childrens Hosp Philadelphia, Human Genet, Philadelphia, PA 19104 USA
[4] Univ Penn, Perelman Sch Med, Philadelphia, PA 19104 USA
[5] Polish Mothers Mem Hosp Res Inst, Dept Genet, Lodz, Poland
[6] Childrens Mem Hlth Inst, Dept Med Genet, Warsaw, Poland