Prader-Willi Syndrome obesity linked to sleep apnoea

Prader-Willi Syndrome is a rare genetic disorder with multiple symptoms, although the best known is a voracious appetite that leads to rampant overeating and obesity.

Now researchers at the Garvan Institute have revealed some insights into the disorder, finding it is also associated with an overactive immune response and may be linked to speel apnoea.

One in 25,000 babies will be born with Prader-Willi Syndrome. Small and floppy at birth, within two years the children start to become fatter because they feel constantly hungry, no matter how much they eat.

Prader-Willi children have such voracious appetites that parents are forced to put locks on refrigerators and place food out of sight and out of reach. The children grow into ravenous obese adults with cardiovascular problems and a short lifespan, some not surviving past their 20s or 30s.

The study was conducted by Dr Alex Viardot and Professor Lesley Campbell from Sydney’s Garvan Institute of Medical Research and involved 12 individuals with Prader-Willi syndrome who were matched with 12 obese individuals who were matched for fat mass.

This matching was crucial in order to isolate effects that were due to the Syndrome rather than as effects of obesity.

The researchers found that individuals with Prader-Willi Syndrome showed an overactive immune response, causing inflammation.

It is known that obesity can trigger an increased immune response with corresponding inflammation, but the Prader-Willi group demonstrated an elevated immune response above that of the obese group.

It was also found that the Prader-Willi group showed a greater frequency of sleep apnoea, where breathing is interrupted during sleep. The researchers believe this sleep apnoea might be one cause for the increased immune response.

“We did this study to find out more about Prader-Willi and to give us better insight into obesity and appetite control generally,” said project leader Professor Campbell.

“Identifying possible causes of the immune activation in this disease will provide targets for treatment, which in turn will improve early mortality.

“The main message from this project was that the Prader-Willi group had more activation of their immune system than the obese-only group.

“And while there is always low-level inflammation associated with obesity, there seemed to be an intrinsic inflammatory process going on in the Prader-Willi group that was excessive.

“Five members of the Prader-Willi group had sleep apnoea, in contrast to one from the obese group, and that may have contributed towards their fired-up immune system.

“We believe that if we treat sleep apnoea, we may at least partially suppress the heightened immune response and decrease associated cardiovascular risk.

“With every small piece of knowledge, such as this study provides, comes hope that we will eventually find the critical clue – the thing that will allow us to turn the appetite switch off.”

The study results were published in the Journal of Clinical Endocrinology and Metabolism.