[1] Univ Groningen, Univ Med Ctr Groningen, Dept Genet, Groningen, Netherlands
[2] Vrije Univ, Dept Human Genet & Amsterdam Reprod, Dev Res Inst, Amsterdam, Netherlands
[3] Vrije Univ, Dev Res Inst, Amsterdam UMC, Amsterdam, Netherlands
[4] Maastricht Univ, Maastricht Univ Med Ctr, Dept Hlth Ethics & Soc, Maastricht, Netherlands
[5] TNO, Dept Child Hlth, Leiden, Netherlands
[6] Dutch Coll Gen Practitioners, Utrecht, Netherlands
[7] Univ Groningen, Univ Med Ctr Groningen, Dept Genet, POB 30 001, NL-9700 RB Groningen, Netherlands