Genetic roots of sleep points, autism could also be entwined | Spectrum
Double diagnosis: when one twin has autism or autism characteristics, the other twin often has insomnia, a new study shows.
The genetic factors influencing autism may overlap with those underlying insomnia, according to a new study of autistic people and their relatives. In contrast, the two conditions show a minimal overlap of environmental influences.
The results could help explain the common coexistence of autism and sleep problems, says lead investigator Mark Taylor, researcher in psychiatric epidemiology at Karolinska Institutet in Stockholm, Sweden. Up to 90 percent of people with autism have sleep disorders, and around 30 percent have a clinical diagnosis of a sleep disorder according to previous research.
“This paper shows that [autistic individuals] who are quite often diagnosed with insomnia and prescribed melatonin to help them fall asleep, ”says Taylor. “But we also consider siblings and relatives in this study, and relatives of autistic people also have a higher risk of developing insomnia.”
The strong overlap between the conditions underscores the importance of diagnosing and treating sleep problems in autistic people, says Philippe Mourrain, an adjunct professor of psychiatry and behavioral science at Stanford University in California who was not involved in the research.
“Sleep problems are overlooked. They’re seen as a by-product – additional symptoms that aren’t worth investigating when it comes to autism, ”he says. In fact, however, poor sleep can affect brain development and affect the severity of autism characteristics.
Taylor and his colleagues used Swedish health registries to identify 50,097 autistic people, along with nearly 56,000 of their full siblings (including 60 identical and 340 dizygoti twins), 31,669 half siblings and 214,665 cousins. They also analyzed data from 500,970 unrelated gender and age-matched controls. They tracked which participants were diagnosed with insomnia – difficulty falling or staying asleep – or were taking melatonin, which was only available by prescription in Sweden before May 2021 when it was available over the counter.
About 23 percent of autistic participants had insomnia or were taking melatonin, compared with 1.1 percent of controls, the study shows. In addition, the relatives of autistic people are also at increased risk of suffering from insomnia; the closer the family member is, the greater their chances. Identical twins, for example, were about 6.6 times the usual chance of suffering from insomnia, while cousins were about 1.3 times the usual chance.
A second analysis of data from 30,558 monozygotic and dizygotic twins in the ongoing Child and Adolescent Twin Study in Sweden found similar results: of 423 autistic twins in this sample, about 39 percent had insomnia or were prescribed melatonin, compared with just 4 percent of those who did not -autistic twins.
When one twin in a pair has autism or autism traits, the other twin often has insomnia, the team found. This trend was more pronounced in identical twins, who share almost all of their genes, than in dizygotic twins, who share only half. Common genetic factors accounted for 94 percent of the correlation, while non-shared environmental factors accounted for only 6 percent.
The results were published in the Journal of Child Psychology and Psychiatry in July.
“Find a genetic correlation [between autism and sleep problems] confirms what we often see clinically, ”said Amanda Bennett, clinical chair of the Autism Integrated Care Program at Children’s Hospital of Philadelphia. “What could really change the practice one day would be if we could identify genetic variations that help us proactively predict and combat these concurrent symptoms.”
Taylor’s team is studying the common occurrence of autism and other characteristics with mental illnesses such as anxiety, depression, schizophrenia, and bipolar disorder. Some traits, including sensory sensitivity, hyperactivity, and anxiety, can contribute to poor sleep in autistic people and are genetically correlated with autism, he says – leaving open the possibility that insomnia is not directly genetically correlated with autism, but rather with other co-occurring ones Conditions.
Quote this article: https://doi.org/10.53053/OOHQ7251