Figure 2

‘Disease Page’ as information portal for each rare inborn error of metabolism. As an example, the page with specific features and online resources for Niemann Pick Disease Type C is presented here. Levels of Evidence are defined as follows: (source: Centre for Evidence-Based Medicine, Oxford UK, www.cebm.net): Level 1a = Systematic Review of Randomized Controlled Trials (RCT), 1b = Individual RCT, 1c = ‘All or None’ (=(prolongation of) survival with therapy); Level 2a = Systematic Review of Cohort Studies, 2b = Individual Cohort Study, 2c = ‘Outcomes Research’ (focused on end results of therapy for chronic conditions, including functioning and quality of life (http://www.ahrq.gov/clinic.outfact.htm)); Level 3 = Systematic Review of Case–control Studies; Level 4 = Individual Case–control Study or Case-series/report; Level 4-5 = Single Case Report; Level 5 = Expert opinion without critical appraisal.