[1] Univ Ulster, Belfast, Antrim, North Ireland
[2] Univ Med Ctr Groningen, NL-9713 AV Groningen, Netherlands
[3] Div Autonome Genet Med, Lausanne, Switzerland
[4] Direcc Salud Publ, Registro Anomalies Congenitas CAV, Vitoria, Spain
[5] Hosp Lillebaelt, Odense, Denmark
[6] Dept Hlth Informat, Guardamangia, Malta
[7] Swansea Univ, Swansea, W Glam, Wales
[8] INSERM, Paris Registry Congenital Malformat, Paris, France
[9] Univ Bergen, Bergen, Norway
[10] Prov Inst Hyg, Antwerp, Belgium
[11] Unifersitaria Ferrara, Azienda Osped, Ferrara, Italy
[12] Dept Publ Hlth, Dublin, Ireland
[13] CNR, Inst Clin Physiol, Pisa, Italy
[14] Otto Von Guericke Univ, Fac Med, Magdeburg, Germany
[15] Johannes Gutenberg Univ Mainz, Univ Med Ctr, D-55122 Mainz, Germany