Medicines for Prader-Willi syndrome

What it is

Prader-Willi syndrome (PWS) is a rare genetic condition that affects many parts of the body and causes a range of physical, developmental, and behavioural features. It is caused by a problem with genes on chromosome 15 (usually a missing or non-working part that would normally be inherited from the father). It is present from birth and is lifelong. PWS has a characteristic pattern that changes with age. In babies, it often causes floppiness (low muscle tone), feeding difficulties and poor growth, and slow development. Then, typically in early childhood, a striking and defining feature develops: a constant, intense feeling of hunger (hyperphagia) that is very difficult to control, so that, without careful management, the person tends to overeat and can gain excessive weight, which — if not managed — can lead to serious obesity and its health consequences. Other features of PWS can include: learning disability (usually mild to moderate); short stature and effects on growth (related to a growth hormone deficiency); underdeveloped sexual development (due to effects on hormones); particular behavioural and emotional features (such as temper outbursts, stubbornness, and rigid or repetitive behaviours); and other associated physical and health features. The intense hunger and the tendency to overeat are central challenges of PWS, and managing food and preventing excessive weight gain is one of the most important aspects of care. PWS is a lifelong condition with no cure, but it is managed with individualised, multidisciplinary support: careful management of diet and food access to prevent overeating and obesity; growth hormone treatment (which is used in PWS and helps growth, body composition, and other aspects); support for development, learning, and behaviour; and management of the various health and hormonal aspects. With good management and support, particularly careful food management, many of the serious consequences (especially obesity) can be reduced, and people with PWS can be supported to live as well as possible. The key messages are that PWS is a rare genetic condition affecting development, growth, and — characteristically — appetite, that the intense hunger and risk of overeating are central challenges, and that careful support and food management help greatly.

How it is treated

Prader-Willi syndrome is managed with individualised, multidisciplinary support, with careful management of food and weight being central, alongside growth hormone treatment, support for development and behaviour, and management of the various health aspects. Diagnosis is confirmed by genetic testing, and the condition is usually managed with input from a range of specialists. Because the intense hunger (hyperphagia) and tendency to overeat are defining and serious features, managing food and preventing excessive weight gain is one of the most important aspects of care: this involves careful management of the food environment and access (for example, structured eating, supervision, and controlling access to food, which is often necessary given the intensity of the hunger), a healthy, calorie-appropriate diet, and physical activity, guided by dietitians and the care team — this is central to preventing the serious obesity that can otherwise develop and its health consequences, and requires ongoing, consistent management and support, often lifelong. Growth hormone treatment is an important part of care in PWS, as it helps with growth, improves body composition (muscle and fat), and has other benefits, and is used under specialist guidance. Other aspects of care include: support for development and learning (with educational support tailored to the individual); support for behaviour and emotional wellbeing (as PWS is associated with particular behavioural features, and behavioural support and strategies help); management of hormonal aspects (such as sexual development and other hormones); management of other associated health features; and monitoring for and managing complications, particularly those related to weight. Physiotherapy and other therapies support movement and development, especially in early childhood (given the low muscle tone). Support for families and carers is very important, given the demands of managing the condition (particularly the food management), and support organisations provide information, strategies, and community. Genetic counselling is offered to discuss the condition and any implications. Care is coordinated and continues through life, adjusting to changing needs. The reassuring messages are that, although PWS is a lifelong genetic condition without a cure, individualised, multidisciplinary support — with careful food and weight management as a central focus, growth hormone treatment, and support for development, behaviour, and health — helps greatly, that careful management can reduce the serious consequences (especially obesity), and that support for the person and family is available; so consistent food management and coordinated specialist care are the keys to living well with PWS.