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43
42
January/February 2018^ DISCOVER^49
LEFT: SCOTT PETERSON/GETTY IMAGES. RIGHT: AUGUSTO ZAMBONATO
The Sleepless Seven: First
Genes Linked to Insomnia
❯
LACK OF SLEEP hurts people’s concentration, mood
and health. And for those with insomnia — defined
as three sleep-deprived nights a week for at least three
months — life can become a nightmare.
The cause of insomnia, which affects 10 percent of the
population, has long been considered psychological. But a
June paper in Nature Genetics identified, for the first time, a
genetic risk for the condition.
A team of international researchers looked for genomic
variations between insomniacs and sound sleepers among
113,000 people in the U.K. and found seven genes linked
to insomnia. One of the genes had been identified as a risk
factor for two sleep disorders: restless leg syndrome and
periodic limb movement. Individuals with the insomnia-
linked genes also appeared predisposed to depression, obesity
and cardiovascular diseases.
Exploring “what these genes actually do and why they
make people vulnerable for insomnia is the next step,”
says study co-author Eus Van Someren, head of the
Sleep & Cognition Group at the Netherlands Institute for
Neuroscience. The research could lead to developing more
effective drugs to treat the condition, he says. MARK BARNA
Genetic Roots
of PTSD
❯
SPOST-TRAUMATIC STRESS
DISORDER (PTSD) affects about
24.4 million Americans annually.
Now, researchers have detailed evidence
that a person’s risk of developing
the disorder — which results from
experiencing traumatic events like rape
and war — is inherited.
The work, published in Molecular
Psychiatry in April, pooled results from 11
studies to analyze data from over 20,000
volunteers. Previous research suggested
genetics might play a role in developing
PTSD. But according to senior author and
Harvard epidemiologist Karestan Koenen,
those findings only inferred heritability.
For this work, Koenen and her team
examined the entire genomes of those
earlier studies’ participants. They found
evidence that not only can PTSD be
passed down through generations, but
also that some related genes are linked
to schizophrenia. They further found that
European-American women are about 30
percent more likely than men overall to be
genetically susceptible to developing PTSD.
Knowing how the condition works on
a genetic level could help experts identify
those most at risk, and tailor treatment
to help them work through their
trauma. LACY SCHLEY