Prader-Willi Syndrome

Prader-Willi Syndrome is a genetic condition caused by the loss of functional genes on the proximal arm of the chromosome 15 inherited from the father. This can be due to a deletion of this portion of the chromosome, or when both copies of chromosome 15 are inherited from the mother.



  • Constant insatiable hunger that leads to obesity
  • Poor muscle tone as an infant (hypotonia)
  • Mild-moderate learning disability
  • Hypogonadism
  • Fairer, soft skin that is prone to bruising
  • Mental health problems, particularly anxiety
  • Dysmorphic features
  • Narrow forehead
  • Almond shaped eyes
  • Strabismus
  • Thin upper lip
  • Downturned mouth


TOM TIP: The key feature everyone remembers for Prader-Willi syndrome is the the insatiable hunger. Feeding can often be a challenge initially due to hypotonia and it is only later that the food seeking and excessive eating occur. It is worth remembering some other key facts about the condition, such as the treatment with growth hormone and the poor muscle tone, so that you know more than just the link with appetite.



There is no cure. Carefully limiting access to food under guidance of a dietician is required to control weight. This usually requires locking food in cupboards, putting a lock on the fridge and even controlling access to rubbish bins. Under dietician guidance they usually require a lower than normal calorie intake, particularly as they tend to have lower activity levels due to poor muscle strength and tone. Everyone that is in contact with the child will need to be educated about limiting access to food, including teachers, carers and relatives.

Growth hormone is indicated by NICE as a treatment for Prader-Willi Syndrome, aimed at improving muscle development and body composition.

Supportive care from the multidisciplinary team to manage features:

  • Dieticians play a very important role
  • Education support
  • Social workers
  • Psychologists or psychiatrists
  • Physiotherapists
  • Occupational therapists


Last updated January 2020