Prader Willi Syndrome

What is Prader Willi Syndrome?

  • Both excessive desire for food and increased risk of obesity are common in Prader-Willi Syndrome (PWS), making nutrition an important topic to discuss!

  • The symptoms of PWS can include many other things outside of nutrition, from learning difficulties to physical and behavioral challenges.

  • PWS is usually diagnosed after birth or in the early years of life. One symptom which can present itself at birth as weak muscle tone and results in ‘floppiness’ in the child. Otherwise, a genetic test can determine a PWS diagnosis.

  • PWS can present in a similar manner as Autism. PWS can often result in ritualistic, repetitive or obsessive behaviors, mood issues or depression or getting confused by social situations.

 
 

Signs & Symptoms

  • Overeating/excessive appetite

  • Overweight/obesity

  • Restricted growth (children are much shorter than average)

  • Learning difficulties

  • Reduced/lack of sexual development

  • Behavior changes

  • Low muscle tone (hypotonia)

Contributing Factors

  • Research states that PWS is caused by some genetic material which is missing on a specific group of genes, specifically on the number 15 chromosome. 

  • This interferes with a part of the brain called the hypothalamus which aids in the production of hormones. The hypothalamus also regulates the appetite and growth hormones, thus excessive appetite and growth issues arise.


Next Steps

Diet

  • Abnormally increased appetite and/or obesity may occur in childhood so nutrition is important for individuals with Prader-Willi Syndrome. It is key to have a healthy nutritious balanced diet and eat a diet within their calorie range for age and gender.

  • If the diet is not controlled and excessive eating occurs regularly, some conditions such as type 2 diabetes or heart failure can occur.

  • Choking is also a heightened hazard with PWS due to quick-paced eating.

  • Fiber is an important component of the diet for anyone but in particular someone with autism and Prader Willi Syndrome. Fiber can be found in fruit, vegetables, whole grains, and nuts & seeds.

  • Fiber allows us to feel fuller for longer, otherwise known as satiety. Fiber reduces constipation and feeds good gut bacteria. Feeding the good gut bacteria means that the gut will strive. There is significant research suggesting once the gut is happy, the behavioral issues are reduced. This can help manage certain symptoms, though it doesn't cure PWS.

  • If you let someone with PWS eat as much they want they will overeat as their typical hunger cues are altered. Eating a balanced diet that includes protein, fat, and fiber at each mealtime and at least two of the three at snack time can help with satiety cues. 

  • With proper diet management, many adults with PWS will have a normal life expectancy and a good quality of life.

Supplements

  • One study stated that those with PWS were not meeting the requirements of vitamin D, calcium, potassium and fiber [5], however this was also true in non-PWS groups. A simple blood test from the GP will let you know if your child is deficient in calcium, vitamin D and/or potassium. 

  • In another study, a probiotic called Limosilactobacillus reuteri (also known as Lactobacillus reuteri or L. reuteri) was given to 71 PWS individuals. L. reuteri has been known to have anti-inflammatory and anti-obesity effects in previous studies [6]. 

    • Within this study, it was observed that social interaction and communication improved as the trial went on. Body mass index significantly decreased for the PWS individuals on the probiotic compared to those not taking the probiotic. There was also a noticeable difference in the gut microbiome where a probiotic was consumed [6]. 

Lifestyle

It is important to inform friends, relatives, teachers and other parents of the child's condition so they do not overeat when the parents are not around. Due to low muscle tone everyday work and chores can be very tiring for PWS individuals. Some lifestyle considerations for PWS include: 

  • Finding an activity they like will help reduce the risk of obesity.

  • In one particular study, it showed that a multifactorial team (including occupational therapy) had a positive influence on health [7]. 

  • Occupational therapists can assist and help to build muscle tone [9].

  • It is recommended to get into good food practices from an early age. A good start is to have the ‘kitchen is closed’ rule. So this means outside of mealtimes and snack times, the kitchen is closed. This will help them and you to keep track of what and when they eat.

  • Increasing the quantity of lower calorie foods is a good option too. Low calorie foods include; veggies, fruit and salads [8].

  • Keeping food out of obvious view is also recommended [8].

  • Food may become a big issue and PWS individuals may start to sneak food away. If it comes to it, cupboards or kitchen doors may have to be locked to prevent excess food from being eaten [8].

  • Daily routine and structure is important and have been shown to help people with PWS cope better [8].

DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.

Prader Willi Syndrome & Autism in the Research

  • PWS may be associated with specific behavioral and psychiatric phenotypes which overlap with ASD [1, 4]. In one particular study, 26.7% of the participants within the study met the criteria of ASD [4].

  • Many of the autistic symptoms in people with PWS are displayed during adolescence and not during childhood [3]. In a systematic review of PWS research in 2015, it stated that the majority of the research was conducted on PWS individuals between the ages of 8 and above [4].

  • According to significant research, there is an association between ASD and an individual who has a duplicate of chromosome 15 from the mother, compared to a duplicate of chromosome 15 from the father [3]. In one particular study, a consistent pattern of autism-like behavioral issues was higher in those with the duplicate chromosome 15 from the mother compared to that of the father [3].

  • It might be worth noting that while there is physical growth occurring, PWS individuals may develop distractibility, inattention and impulsivity. However, obesity and poor muscle tone may prevent the behavioral traits from being recognized and some assessment tools can fail to detect them [3].


  • [1] Butler MG, Miller JL, Forster JL. Prader-Willi Syndrome - Clinical Genetics, Diagnosis and Treatment Approaches: An Update. Curr Pediatr Rev. 2019;15(4):207-244. doi: 10.2174/1573396315666190716120925. PMID: 31333129; PMCID: PMC7040524.

    [2] Overview: Prader-Willi Syndrome. NHS UK Website. Accessed October 3. Page last reviewed 28 January 2-21. https://www.nhs.uk/conditions/prader-willi-syndrome/

    [3] Ogata H, Ihara H, Murakami N, Gito M, Kido Y, Nagai T. Autism spectrum disorders and hyperactive/impulsive behaviors in Japanese patients with Prader-Willi syndrome: a comparison between maternal uniparental disomy and deletion cases. Am J Med Genet A. 2014 Sep;164A(9):2180-6. doi: 10.1002/ajmg.a.36615. Epub 2014 May 21. PMID: 24850752; PMCID: PMC4278412.

    [4] Bennett JA, Germani T, Haqq AM, Zwaigenbaum L. Autism spectrum disorder in Prader-Willi syndrome: A systematic review. Am J Med Genet A. 2015 Dec;167A(12):2936-44. doi: 10.1002/ajmg.a.37286. Epub 2015 Aug 29. PMID: 26331980.

    [5] Mackenzie ML, Triador L, Gill JK, Pakseresht M, Mager D, Field CJ, Haqq AM. Dietary intake in youth with prader-willi syndrome. Am J Med Genet A. 2018 Nov;176(11):2309-2317. doi: 10.1002/ajmg.a.40491. Epub 2018 Sep 14. PMID: 30216657.

    [6] Kong XJ, Liu K, Zhuang P, Tian R, Liu S, Clairmont C, Lin X, Sherman H, Zhu J, Wang Y, Fong M, Li A, Wang BK, Wang J, Yu Z, Shen C, Cui X, Cao H, Du T, Wan G, Cao X. The Effects of Limosilactobacillus reuteri LR-99 Supplementation on Body Mass Index, Social Communication, Fine Motor Function, and Gut Microbiome Composition in Individuals with Prader-Willi Syndrome: a Randomized Double-Blinded Placebo-Controlled Trial. Probiotics Antimicrob Proteins. 2021 Dec;13(6):1508-1520. doi: 10.1007/s12602-021-09800-9. Epub 2021 Jun 11. PMID: 34115318; PMCID: PMC8578098.

    [7] Campbell N, Van Zant S, Lammers J. Multifactorial influences on successful health outcomes for an adolescent with Prader-Willi syndrome: a qualitative case study. Physiother Theory Pract. 2022 Jan 31:1-9. doi: 10.1080/09593985.2022.2036277. Epub ahead of print. PMID: 35100943.

    [8] NHS, 2021. Management of Prader-Willi Syndrome. [Online] Available at: https://www.nhs.uk/conditions/prader-willi-syndrome/living-with/ [Accessed 06 09 2022].

    [9] PWSA UK, 2022. Dietary Management. [Online] Available at: https://www.pwsa.co.uk/dietary-management [Accessed 06 09 2022].

Authors

Jennifer Finlay-Mulligan, BSc, ANutr

Edited and Reviewed by Brittyn Coleman, MS, RDN/LD, CLT

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