Page 176 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

Chapter 6
Abstract
The 22q11.2 deletion syndrome (22q11.2DS) has an estimated prevalence of
1:2148 live births and is associated with an increased risk of schizophrenia,
cognitive decline and early-onset Parkinson’s disease. Because retinal
and cerebral tissue share embryological, physiological and anatomical
characteristics, retinal blood vessel morphology and retinal nerve fiber
layer (RNFL) thickness have been proposed as non-invasive biomarkers for
psychiatric and neurodegenerative disorders. In this exploratory study, we
examined these potential biomarkers in adults with 22q11.2DS relative to
controls and in relation to age. Therefore, the central retinal artery and vein
equivalent, fractal dimension, and vascular tortuosity, obtained through
fundoscopy, and peripapillary RNFL and macular thickness, obtained
through optical coherence tomography, were compared between adults
with 22q11.2DS and sex- and age-matched controls. Mean retinal vascular
fractal dimension and tortuosity values were significantly higher in the
group of adults with 22q11.2DS than in controls (p<0.001; p<0.001). RNFL
was thicker in the nasal segment (p=0.002) in 22q11.2DS, and a trend for
thinner RNFL in the nasal inferior segment (p=0.05) was found. There were
significant negative correlations with age for fractal dimension (p<0.001)
and RNFL thickness in the global (p=0.007), temporal inferior (p=0.005) and
temporal superior (p=0.04) segments in adults with 22q11.2DS, but not in
controls. In conclusion, our results indicate higher retinal vascular fractal
dimension and tortuosity, and a decrease in fractal dimension and RNFL
thickness in relation to age in adults with 22q11.2DS. Our findings support
future studies that focus on retinal fractal dimension and RNFL thickness
as potential biomarkers for age-related manifestations in 22q11.2 including
psychotic and (early) neurodegenerative disorders.
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