Different types

of rare genetic causes of hard-to-control hunger and obesity


Depending on the genes that are affected, different genetic conditions can lead to hard-to-control hunger (hyperphagia) and obesity, as well as a wide range of other physical and mental symptoms.1

Some of the information here may be a bit complicated but don’t worry. If you think you or someone you care about may be affected, the important thing is to speak to your doctor. Find help with having that conversation with our discussion guide

If a genetic condition is suspected by your doctor, a blood or saliva test can be used to help confirm the diagnosis. You can learn more about genetic testing here.

Bardet-biedl syndrome

Bardet-Biedl (pronounced BAR-day BEED-el) syndrome, also known as BBS, is a type of rare MC4R pathway disease and has a wide range of signs, including hard-to-control hunger and childhood obesity. Different people living with BBS will have different signs of the disease, some may have a lot and some may have only a few.1

Monogenic obesity

When a change in one gene leads to hard-to-control hunger and obesity, this is called monogenic obesity. This change in the gene can be inherited from parents, in the same way that genes for eye and hair colour are passed down.2

Prader-Willi syndrome

Prader-Willi (PRAH-dur VIL-e) syndrome causes a number of physical symptoms, including hard-to-control hunger, early childhood obesity, learning difficulties and behavioural challenges.1

Alström syndrome

Alström syndrome (Al-Strom) is a rare genetic condition that affects multiple organs in the body, including the kidneys, brain, heart, pancreas and liver.4

What can you do?

If you think you have spotted one or more of these signs in yourself, or your child, download and complete our discussion guide to help prepare for an appointment with your doctor or nurse.


  • 1

    Forsythe E, et al. Orphanet J Rare Dis. 2023; 18(1): 12

  • 2

    Huvenne H, et al. Obes Facts. 2016; 9(3): 158-173

  • 3

    Driscoll DJ, et al. GeneReviews. Seattle (WA): University of Washington, Seattle; 1993–2023

  • 4

    Marshall JD, et al. Current Genomics. 2011; 12: 225-235