1. From the Department of Medical Genetics, Family Federation of Finland, Helsinki, Finland;
2. Department of Medical Genetics, University of Helsinki and the
3. Folkhälsan Institute of Genetics, Helsinki, Finland;
4. Helsinki University Central Hospital, HD-Laboratories, Division of Medical Genetics, Haartman Institute, Helsinki, Finland; and the
5. Department of Epidemiology and Health Promotion, National Public Health Institute, Helsinki, Finland.