Prader-Willi syndrome is a chromosomal disorder which affects both sexes.

The syndrome has many characteristics, the most obvious of which is an insatiable appetite. This starts with an increasing interest in food during infancy and can develop into an obsession by the time the child starts school, leading to rapid weight gain, obesity and disease, with a shortened life-expectancy unless the diet can be carefully and strictly controlled. Children with Prader-Willi Syndrome may also have a growth hormone deficiency and various other characteristics.

Children with Prader-Willi Syndrome often share similar physical features, such as almond-shaped eyes, small mouth, hands and feet. As babies these children are usually weak and floppy and most of them suffer feeding difficulties from the start. They have weak muscle tone and their physical development and speech may be delayed.

Children with Prader-Willi Syndrome have specific, moderate or severe learning difficulties and generally lower than average cognitive abilities.

As well as an increased appetite, Prader-Willi sufferers also have a reduced biological need for calories, which exacerbates the damaging effects of their over-eating. Exercises to improve their muscle tone can be a great help.

Key characteristics

A child with Prader-Willi Syndrome may:

  • be of short stature (not all sufferers) and with small features (mouth, hands, feet)
  • have a large or obsessive appetite and therefore gain weight rapidly
  • have moderate, specific or severe learning difficulties and low cognitive ability
  • have weak and floppy muscle tone
  • lack physical coordination and have problems with fine and gross motor skills
  • be placid and easy-going, although they may have temper tantrums related to food
  • have obsessive and compulsive behaviour
  • pick their skin or possibly self-harm
  • continually repeat a question or statement
  • have poor auditory processing and have difficulty carrying out verbal instructions
  • have problems with sequencing
  • think in a rigid and orderly way
  • find changes in routine difficult to cope with
  • have problems making choices
  • have poor short-term memory
  • have poor social skills and interactions (they will probably find adults easier to talk to)
  • find it difficult to work in a group
  • be manipulative or dishonest to obtain food.

Support strategies

You may need to:

  • use visual aids and cues as much as possible
  • help them to develop strategies to improve social skills, auditory memory, sequencing, making choices and following instructions
  • follow an exercise programme to help them to strengthen muscle-tone and build physical coordination
  • if they repeatedly ask a question, ask the question back as they will probably know the answer already – praise them
  • help them to develop strategies to cope with changes in routine
  • provide frequent opportunities for practice and consolidation of skills and concepts.

Support agencies

Prader-Willi Syndrome Association (PWSA UK)