1. Department of Clinical Genetics, Section Community GeneticsEMGO Institute for Health and Care ResearchVU University Medical CenterAmsterdamThe Netherlands
2. School for Public Health and Primary CareDepartment of General PracticeMaastricht UniversityMaastrichtThe Netherlands
3. Department of Clinical Genetics, Section Community GeneticsEMGO Institute for Health and Care ResearchVU University Medical CenterBS7 D247, P.O. Box 70571007MBAmsterdamThe Netherlands
4. Julius Center for Health Sciences and Primary CareUniversity Medical Center UtrechtUtrechtThe Netherlands
5. Department of General Practice & Elderly CareVU Medical Centre AmsterdamAmsterdamThe Netherlands