[1] Danish Canc Soc Res Ctr, Childhood Canc Res Grp, Copenhagen, Denmark
[2] Danish Canc Soc Res Ctr, Stat & Data Anal, Copenhagen, Denmark
[3] Aarhus Univ Hosp, Ctr Rare Dis, Aarhus, Denmark
[4] Copenhagen Univ Hosp, Ctr Rare Dis, RAREDIS Database, Aarhus, Denmark
[5] Aarhus Univ Hosp, Aarhus, Denmark
[6] Univ Oklahoma, Dept Pediat, Oklahoma City, OK USA
[7] Aarhus Univ, Fac Hlth, Dept Clin Med, Aarhus, Denmark
[8] Univ Hosp, Aarhus, Denmark