Brain cells receive sensory inputs from the outside world and send signals throughout the body telling organs and muscles what to do. Although neurons comprise only 10% of brain cells, their functional and genomic integrity must be maintained over a lifetime. Most dividing cells in the body have well-defined checkpoint mechanisms to sense and correct DNA damage during DNA replication.

The cause of rare diseases is increasingly being detected through genome sequencing, which involves reading the entire human DNA by first breaking it into small pieces—short reads. Christian Gilissen, Lisenka Vissers, and colleagues found that a new technique using long reads is even more effective at detecting complex causes. They report that 80–90% of cases were detectable, as stated in The American Journal of Human Genetics.