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Genetic link to sleepwalking
A study published in Neurology has provided further evidence that the phenomenon of sleepwalking can have a genetic basis.
The study set out to determine the inheritance of sleepwalking across four generations of a family of extreme sufferers, and to identify the chromosomal region responsible. Nine sleepwalkers and thirteen unaffected family members were interviewed and DNA samples collected and analysed.
The results indicated that the family’s sleepwalking was inherited as an autosomal dominant disorder with reduced penetrance, meaning that inheriting a single copy of the gene responsible can be enough to cause the condition, but that it will not always cause it to appear; perhaps due to lifestyle factors or interaction with other genes. A linkage study of this type is not able to pinpoint the specific gene concerned, but was able to narrow it down to a region on chromosome 20 containing around 28 genes.
Sleepwalking is a widespread phenomenon, particularly during childhood, and can potentially put sufferers in dangerous situations. It had previously been known that the condition was heritable, but it had not been linked to a particular chromosome or region. Since this study is a small-scale one within a family of particularly severe sleepwalkers though, it doesn’t necessarily follow that the genomic region identified here is responsible for the condition in those with less severe or variant forms of the disorder. The researchers themselves point out that since other studies have shown different inheritance patterns, it is likely that sleepwalking has a number of genetic causes. Further studies will be required to determine how widely applicable these findings are, and also to identify the specific genes involved and the underlying mechanism before this work can point to possible therapies.