Regular doses of a widely used fertility drug may help to boost cognitive skills in people with Down’s syndrome, a pilot study led by researchers from France and Switzerland has suggested.

In a small-scale trial, researchersExternal link fitted seven men who have Down’s syndrome with a pump that provided a dose of GnRH, a gonadotropin-releasing hormone, every two hours for six months.

Six out of the seven men showed moderate cognitive improvements after the treatment, including in attention and being able to understand instructions, compared with a control group who were not given the hormone.

The team from the Lille Neuroscience & Cognition laboratory and Lausanne University Hospital (CHUV) behind the work said brain scans of the participants, who were aged between 20 and 37, given the hormone suggest they underwent changes in neural connectivity in areas involved in cognition.

“[People] with Down’s syndrome have cognitive decline which starts in the 30s,” Professor Nelly Pitteloud, co-author of the study from the University of Lausanne, told The Guardian. “I think if we can delay that, this would be great, if the therapy is well tolerated [and] without side effects.”

Down syndrome, also known as trisomy 21, is the most common genetic cause of intellectual disability, affecting about one in 800 babies. It occurs when a person is born with an extra copy of chromosome 21. Down syndrome results in a variety of clinical manifestations, including decline in cognitive capacity. With age, 77% of people with the condition experience symptoms similar to those of Alzheimer's disease. Gradual loss of the ability to smell is also common.

The researchers previously found mice with an extra copy of chromosome 16 experienced an age-related decline in cognition and sense of smell, similar to that seen in people with Down’s syndrome. In a series of experiments, the team found regular doses of gonadotropin-releasing hormone boosted both the sense of smell and cognitive performance of these mice.

Their work was published in Science journal on September 1.

Following these promising findings, the researchers are considering the launch of a larger study – with the inclusion of women – to confirm the efficacy of this treatment in people with Down syndrome, but also for other neurodegenerative conditions such as Alzheimer's disease.

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