Does Aneuploidy in the Brain Play a Role in Neurodegenerative Disease?

Aneuploidy, a state in which cells exhibit copy number changes of (parts of) chromosomes,
is a hallmark of cancer cells and, when present in all cells, leads to miscarriages
and congenital disorders, such as Down syndrome. In addition to these well-known roles
of aneuploidy, chromosome copy number changes have also been reported in some studies
to occur in neurons in healthy human brain and possibly even more in Alzheimer’s
disease (AD). However, the studies of aneuploidy in the human brain are currently under
debate as earlier findings, mostly based on in situ hybridization approaches, could not be
reproduced by more recent single cell sequencing studies with a much higher resolution.
Here, we review the various studies on the occurrence of aneuploidy in brain cells from
normal individuals and Alzheimer’s patients. We discuss possible mechanisms for the
origin of aneuploidy and the pros and cons of different techniques used to study aneuploidy
in the brain, and we provide a future perspective.