Page 215 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

General discussion and future perspectives
22q11.2DS would be needed to study the efficacy of treatment interventions
for trauma and to identify if and how these interventions need to be adapted
to the strengths and weaknesses of individuals with 22q11.2DS. Another
example can be found in our study of hearing in chapter 4. About one out of
three adults with 22q11.2DS were prescribed hearing aids but reported not
to use them.71, 72 Given the high prevalence of hearing loss and the impact it
may have on daily life functioning, strategies to increase the use of hearing
aids may be examined.
Second, longitudinal studies starting in childhood up to late adulthood in
individuals with different GNDs are needed to further close the knowledge
gap regarding conditions that develop over the life course.46, 62 Since genetic
variants associated with GNDs are often identified at an early age, long-
term follow up of individuals with these GNDs provides the opportunity to
generate knowledge of disease trajectories.73, 74 The need for longitudinal
studies starting early in life is further emphasized by the fact that symptoms
of late-onset disorders such as motor symptoms of Parkinson’s disease
often present after cells, such as dopaminergic neurons, have already
died. Ideally, future studies include comprehensive (epi)genetic testing,75
detailed phenotyping and assessment of environmental factors (such as
diet, physical exercise, stress and trauma)76 in minor to severely affected
individuals. In order to obtain adequate sample sizes of individuals with
GNDs multi-center and/or consortia studies are required.66 Longitudinal
studies are crucial for the identification of early predictors and biomarkers
for late-onset disorders, such as proposed in chapter 6, for optimizing
screening and monitoring of at-risk groups, and for identifying windows
of opportunity for treatment interventions. Qualification of retinovascular
and retinoneural parameters as susceptibility biomarkers for psychosis or
neurodegenerative disorders in 22q11.2DS depends on whether the change
in these parameters explain the change in clinical state (e.g., from normal
cognitive functioning to cognitive decline). Therefore, longitudinal studies
would be needed to evaluate such parameters as susceptibility biomarkers
in 22q11.2DS.
Third, cross-GND studies may help to understand differences and overlap
between GNDs and identify, potentially shared, underlying mechanisms
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