Those are interesting cases. A similar but more ubiquitous strangeness is somatic mosaicism, specifically in the brain where it seems that "no two neurons are genetically alike."

I was in line for the Terminator ride at Universal Studios when I stumbled onto this article a few years back. Couldn't stop thinking about it the rest of the trip.

https://www.scientificamerican.com/article/scientists-surpri... “The idea is something that 10 years ago would have been science fiction,” says biochemist James Eberwine of the University of Pennsylvania. “We were taught that every cell has the same DNA, but that’s not true.”

Edit:

Reading into this more again for the first time in a while. I'm amazed at how large some of these differences are. Many having 1 million base pair copy number variants.

"Single cell sequencing of endogenous human frontal cortex neurons revealed that 13%-41% of neurons have at least one megabase-scale de novo CNV, that deletions are twice as common as duplications, and that a subset of neurons have highly aberrant genomes marked by multiple alterations." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3975283/

Couple this with...

"Megabase-scale copy number variants (CNVs) can have profound phenotypic consequences. Germline CNVs of this magnitude are associated with disease and experience negative selection. However, it is unknown whether organismal function requires that every cell maintain a balanced genome. It is possible that large somatic CNVs are tolerated or even positively selected." https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4772019/

I can't imagine our brains are just accumulating mutations of this size for no reason.

My favorite theory so far is that it has to do with memory indexing. https://www.frontiersin.org/articles/10.3389/fgene.2020.0037...