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General discussion and future perspectives2078a history of chronic otitis media were related to more severe hearing loss. For PTSD, described in chapter 7, no relationship was found with either sex or full-scale intelligence quotient. These results may provide clues to which individuals may be at increased risk of conditions that develop over the life course. However, it is important to take into account the retrospective study design, that makes it impossible to draw conclusions about causality.With respect to prediction, ideally, a risk biomarker (a defined characteristic that is measured as an indicator of normal biological processes, pathogenic processes or responses to an exposure or intervention, according to the FDANIH working group)33 could be used to identify individuals with 22q11.2DS with an increased risk of developing, for example, Parkinson’s disease or schizophrenia. This would facilitate screening and early interventions in individuals that are of increased risk, and may potentially limit hospital visits and examinations for those who are not. In chapter 6, retinovascular and retinoneural parameters were explored in adults with 22q11.2DS, and outcomes were compared with those in controls. The rationale for this lies in the fact that these parameters may possibly be used as biomarkers for psychiatric and neurodegenerative disorders in 22q11.2DS, given similarities with cerebral tissue; changes may reflect cerebral vascular and neural changes.34-39 Fundoscopy and optical coherence tomography (OCT) are non-invasive imaging techniques that were used to visualize and quantify these retinal parameters. OCT and fundoscopy have benefits over brain imaging, because they are faster, less-expensive, easier to operate and can therefore be used in smaller hospitals or other care facilities.37, 40 Results showed differences in retinovascular parameters between adults with 22q11.2DS and controls. In addition, some retinovascular and retinoneural parameters decreased with age in adults with 22q11.2DS but not in controls. Unfortunately, due the retrospective study design and lack of standardized assessments of cognitive function and psychosis in this study, it was not possible to compare these parameters between adults with 22q11.2DS with and without psychosis or cognitive decline. However, findings in adults with 22q11.2DS compared to controls and in relation to age were in the same direction as results reported in previous studies in community-based schizophrenia and neurodegenerative disorders,41-44and support future studies that focus on these parameters as potential