Page 45 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

Parkinsonism in GNDs
Discussion
In this first systematic literature review on parkinsonism in patients with
GNDs, we provide a comprehensive overview of phenotypic characteristics
and proposed pathophysiology in 69 different GNDs, based on a total of
422 patients. The main messages and implications of this review can be
found in Figure 3.
Parkinsonism has been reported in a growing number of GNDs. This number
may be expected to further increase given advances in clinical genetic
testing and an increase in life expectancy due to improved medical care for
patients with GNDs. Parkinsonism in these populations however appears to
be underrecognized in clinical practice and to be an understudied research
topic.93-95 An explanation may be that, on the one hand, patients with GNDs
may not always be aware of motor symptoms and may not be capable to
express their symptoms adequately. Professionals on the other hand may
attribute motor symptoms to manifestations of the GND, antipsychotic
medication-induced parkinsonism or co-existing neurologic disorders,
while in fact they may miss a treatable condition of parkinsonism.82
Phenotypic characteristics
Many patients showed the typical phenotypic characteristics found for
patients with Parkinson’s disease: presence of cardinal motor signs, a good
response to antiparkinsonian medication and reduced DAT binding with
dopaminergic imaging. However, there were some notable findings. For
example, almost half of the patients included in our review were female,
atypical for idiopathic Parkinson’s disease sex distribution,96 and the median
age at motor onset was 26 years, much younger compared to age-related
parkinsonism in the general population.97, 98 Also, many patients had co-
existing neurologic disorders, of which dystonia, seizures, and ataxia were
most common.99, 100 While previous research has suggested that patients
with neurodevelopmental disorders may be susceptible to drug-induced
parkinsonism,93, 101 drug-induced parkinsonism as the main cause was
reported in only two patients.
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