What’s passed down from your parents, grandparents and ancestors can impact the way you sleep. In some cases, genetics can be beneficial.

For instance, the short-sleep gene allows people to better cope with sleep loss.

Other families have less helpful genes, like vulnerability to insomnia caused by depression. And rarest of all, a few families in the world carry the ticking time bomb of a gene that causes fatal familial insomnia – a degenerative condition that blurs the boundaries between sleep and wakefulness, eventually ending in death.

A group of researchers from Washington University School of Medicine have discovered a family with four generations of sleepwalkers. Nine out of 22 members of the family have been sleepwalkers. And they may hold the key to finding the cause – and potentially a cure – for sleepwalking.

So far the researchers have been able to identify the chromosomal location that contains the family’s sleepwalking gene. Further research is needed to identify the exact gene.

It’s been long known that sleepwalking is a highly heritable condition. Sleepwalking and other parasomnias such as sleep talking and bedwetting are not uncommon in childhood. About 10 percent of children sleepwalk compared to only 2 percent of adults.

It appears researchers are closer to learning why that 2 percent still sleepwalk.