Is there a genetic link between obesity, dementia, and Down syndrome?

BarcelonaPeople with Down syndrome are more likely to consume sugars and fats uncontrollably and suffer from obesity and metabolic diseases such as diabetes due to a genetic alteration. And all of this can harm them cognitively, according to a pioneering European study led by the Center for Genomic Regulation (CRG) and the Hospital del Mar in Barcelona. "It's not just a question of weight or aesthetics; in Down syndrome, obesity is a risk factor for cognitive impairment and certainly for neurodegeneration," said Dr. Mara Dierssen, leader of the cellular and systems neurobiology group of the systems biology program at the CRG and president of the Consell (Spanish Consell).

The research has found that the DYRK1A gene makes it harder for people with Down syndrome to control their urge to eat, especially when it comes to sweets and fats. This genetic alteration also makes them four times more likely to suffer from type 2 diabetes, insulin resistance, and other pancreatic or liver problems. If we add a lack of exercise, all this makes them more prone to becoming overweight or obese than the general population, and they may suffer from it earlier. "In animal models, we have seen that if [the gene] is overactivated, it prioritizes sweet and salty foods, so there is a genetic predisposition to prefer these foods," Dierssen explained.

Therefore, using animal models, the study has found that greater consumption of quality proteins, vegetables, and whole grains can improve the cognitive ability of these individuals. Differences between the sexes have also been observed: while women with Down syndrome have higher cognitive performance, they are also more affected by metabolic disorders. Dierssen noted that people with this genetic disorder, which involves having an extra copy of chromosome 21, are at "a very high risk of diabetes and obesity" in childhood and adolescence, much earlier than the rest of the population.

Dietary discipline

This particularity is also attributed to the eating habits of people with Down syndrome and those of their families, especially mothers. Therefore, experts recommend that families exercise a great deal of discipline when it comes to denying certain food treats and exercising daily, especially during childhood, adolescence, and young adulthood. Finally, it has also been found that the social stress of those affected, caused by the bullying or stigma, can lead to further overweight.

The coordinator of integrated pharmacology and systems neuroscience at Hospital del Mar, Rafael de la Torre, points out that some of these recommendations also apply to patients with Alzheimer's, who develop the disease in adulthood. However, people with Down syndrome should begin treatment from birth. And if it's necessary to change the eating and exercise habits of those affected, it's also necessary for their parents. In this regard, De la Torre pointed out that dementia is decreasing in the most advantaged socioeconomic classes thanks to everyday habits, while it continues to increase in the lower classes. Therefore, he has called for the involvement of public authorities to counteract this bias.

Preventing dementia

People with Down syndrome have a shorter life expectancy than the rest of the population, around 60 years, but this life expectancy has also been increasing, with some reaching 80. Because they are more likely to suffer from Alzheimer's disease in later life, researchers have highlighted that good lifestyle habits and a healthy diet can not only prevent cognitive decline but could also help delay the onset of dementia.

Organizations for people with this disability, such as Down Catalunya and Down España, as well as La Casa de Carlota, a design studio specializing in hiring people from this group, participated in this research.