Page 50 - Characterization of genetic neurodevelopmental disorders at adult age, with a focus on 22q11.2 deletion syndrome - Emma Boersma

Chapter 2
nature of most studies. Notably, given the large number and wide spectrum
of genetically and clinically heterogenous disorders, the absence of a perfect
classification system that would prevent any inconsistency in inclusion/
exclusion of reports, and differences in availability of information among
genetic neurodevelopmental disorders, we cannot rule out the possibility
of some inconsistencies in inclusion/exclusion of reports. Also, on the one
hand, because non-English reports, studies lacking detailed information on
the genetic disorder and/or criteria for parkinsonism, and studies reporting
on genetic conditions with less than three reported cases, were excluded,
this review may not have captured all relevant publications. On the other
hand, as we included all conditions listed in HPO as “neurodevelopmental
abnormality”, we may have included conditions that should not be
considered to affect brain development. Heterogeneity in reporting made
summarization of results difficult, hampering comparability between GND
phenotypic characteristics. For example, the percentages depicted in the
heat map color scheme were based on the availability of data, that greatly
varied from one report to the other (Figure 1 and Supplementary Figure S2).
Publication bias will have influenced the findings. Variable strength of the
evidence linking genes to phenotypes and the preliminary nature of some
findings should be taken into account.
Conclusion
Parkinsonism has been reported in many GNDs. Findings from this study
may provide clues for further research and improve management of
patients with GNDs and/or parkinsonism.
Acknowledgement
Agnies van Eeghen is member of ERN-ITHACA.
Funding
This work was supported financially by Stichting Wetenschappelijk
Onderzoek, ‘s Heeren Loo (#2210100). The funder had no role in the design
and conduct of the study, preparation of the review, or approval of the
manuscript.
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