Health condition
Prader-Willi syndrome in adults
Prader-Willi syndrome in adulthood centres on lifelong management of hyperphagia - a genetically driven absence of satiety - alongside hormone deficiencies, bone, metabolic and mental health care, with food security as the foundation.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
Which gene and test confirm it, who should be tested in the family, and which specialist to see.
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Caused by loss of paternal gene expression at chromosome 15q11-q13 (deletion, maternal uniparental disomy, or imprinting defects) - recurrence risk for parents is usually low
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Hyperphagia is neurological, not behavioural weakness: without external food security, life-threatening obesity follows
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Adult checklist: growth hormone assessment (benefits continue in adulthood), sex hormone replacement, thyroid, glucose, bone density, sleep apnoea, scoliosis and skin picking
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Mental health matters: anxiety, rigidity and - particularly with uniparental disomy - psychosis risk need informed support
Understanding the condition
What it is and what happens next.
What causes it, how it is confirmed, and the testing and specialist routes available in the UK.
What it is and how it presents
Adults with PWS live with an appetite system that never signals fullness, coupled to a slower metabolism, so weight control depends on structured environments - locked food storage, supervised meals, consistent routines - that respect the biology rather than testing willpower that the syndrome has removed. Around this core, hormone deficiencies stack: most adults are growth hormone and sex hormone deficient, both replaceable with measurable gains in body composition, bone and energy; and gastric problems deserve unusual caution, since high pain thresholds can mask emergencies.
Testing, surveillance and specialist care
The best outcomes come from specialist multidisciplinary follow-up - endocrinology, dietetics, mental health and, where needed, specialist residential settings - with an adult clinic reviewing hormones, bones, glucose and sleep annually. Genetic subtype confirmation retains value in adulthood, informing psychosis vigilance and giving families precise counselling. NHS clinical genetics services carry some of the longest waits in the health service, often many months for a first appointment, whereas private genetic testing and a specialist review can typically be arranged within around two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a endocrinologist experienced in PWS, within multidisciplinary care. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any emergency symptoms.
Frequently asked
Common questions about Prader-Willi syndrome in adults.
Quick, plain-English answers to what people ask us most.
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What is Prader-Willi syndrome in adults?
Prader-Willi syndrome is a genetic condition present from birth that affects development, behaviour, and, notably, appetite regulation; in adulthood, ongoing management focuses particularly on weight, behaviour, and associated health conditions.
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What causes Prader-Willi syndrome?
It's caused by a loss of function of specific genes on chromosome 15, usually due to a missing or non-functioning paternal copy of this chromosome region, occurring in most cases without it being inherited from an affected parent.
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What are the features in adults with Prader-Willi syndrome?
Persistent, intense hunger (hyperphagia) leading to a high risk of significant obesity if not carefully managed, mild to moderate learning difficulties, behavioural challenges, and specific hormone deficiencies affecting growth and reproductive function are common.
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Is Prader-Willi syndrome serious?
Yes, particularly due to the risk of severe obesity and its associated health complications if appetite and food access aren't carefully managed throughout life, alongside other health considerations needing ongoing specialist input.
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Is Prader-Willi syndrome hereditary?
It's a genetic condition, but in the majority of cases it occurs due to a new genetic event rather than being directly inherited from an affected parent, meaning the risk of a further affected child for most parents is low.
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Can Prader-Willi syndrome be treated?
There's no cure, but a comprehensive management approach, including strict food security measures, growth hormone treatment where appropriate, and support for behavioural and psychological needs, significantly improves quality of life and health outcomes.
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How is weight managed in adults with Prader-Willi syndrome?
Careful, consistent control of food access and environment, alongside regular physical activity and specialist dietetic input, is essential lifelong, given the persistent and intense hunger drive characteristic of the condition.
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What other health issues are common in Prader-Willi syndrome?
Sleep-disordered breathing, scoliosis, osteoporosis, and specific hormone deficiencies (affecting growth, thyroid, and reproductive function) are common and benefit from regular specialist monitoring throughout adulthood.
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How is Prader-Willi syndrome diagnosed?
Genetic testing confirms the specific chromosomal abnormality responsible, usually performed in early childhood, though the diagnosis and its implications continue to be relevant and require appropriate care planning throughout adult life.
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When should I see a specialist, and how quickly can I be seen privately?
Adults with Prader-Willi syndrome benefit from regular specialist multidisciplinary follow-up; for additional or second-opinion specialist input, private assessment is typically available within about two weeks, faster than some NHS specialist service waiting times.