Page 209 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

General discussion and future perspectives
a 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 FDA-
NIH 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,41-44
and support future studies that focus on these parameters as potential
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