Prader-Willi syndrome is a rare genetic disability. The main characteristics are muscle weakness, short stature and a lack of satiety, which often leads to obesity. Learn more about symptoms, causes, and treatment options.
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The Prader-Willi syndrome (PWS for short) is named after the Swiss pediatricians Andrea Prader and the pediatricians Heinrich Willi, who first described the genetic disease in 1956. An estimated 1 in 15,000 children is born with the inherited condition. The lives of people with PWS have improved significantly in recent years, primarily through early psychosocial support and hormone therapy.
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How does Prader-Willi Syndrome develop?
A defective gene on chromosome 15 is responsible for the disease. In about 70 percent of cases, a piece of chromosome 15 inherited from the father is missing (paternal deletion). About 30 percent of the diseases involve problems with the structure and function of the chromosome. Because the syndrome has a genetic cause, it is also referred to as a hereditary disease.
The genetic defect results in changes in processes in the diencephalon – more precisely the hypothalamus. This part of the brain acts as an important control center of the body and is responsible for, among other things, the regulation of food intake, the control of emotional and sexual behavior and the production of growth hormones.
What is Prader-Willi Syndrome?
The Prader-Willi syndrome usually becomes noticeable in infancy. Newborns appear very lethargic, are conspicuously quiet and sleep a lot. Feeding is often very difficult because babies with PWS rarely suck and swallow. As a result, they are often underweight, which may necessitate feeding through a nasogastric tube.
The weight problem usually changes fundamentally at the age of two to three years: Because then children with PWS develop an almost food addiction. Since they do not feel full and are less active than other children, there is an increased risk of developing enormous overweight (obesity).
Other PWS features are:
Muscle hypotonia: Over time, children get stronger, but a certain degree of muscle weakness usually remains. A hunchback with curvature of the spine can develop in connection with obesity.
behavioral problems: Especially from school age, people with Prader-Willi syndrome sometimes react defiantly and irascibly and are difficult to calm down. Triggers are unforeseen changes in the daily routine or new situations, as they prefer clear structures and rituals. Anger outbursts decrease with puberty, but many suffer from depressive phases.
short stature: The delayed growth is already noticeable in infancy; On average, women with PWS reach a height of 146 centimeters, men 152 centimeters.
Underdevelopment of the sex organs: Undescended testicles are common in boys and underdeveloped labia in girls. People with PWS are often infertile.
cognitive impairments: Intelligence is often diminished. In particular, the development of language and gross motor skills is usually delayed in children with PWS.
As with Down syndrome, the range and severity of the disorders can vary greatly.
How is Prader-Willi Syndrome diagnosed?
Already during pregnancy it is usually noticed that babies with PWS are more inactive than other fetuses – they move less in the mother’s womb. In addition, physical characteristics of the newborn after birth suggest a genetic defect:
- birth weight is very low
- there is a pronounced muscle and drinking weakness
- the face is narrow, the eyes are almond-shaped
- the skull is often elongated, hands and feet very small
- the mouth has a triangular shape
- Skin and hair are usually lighter than father and mother
- the spine may be bent in an S-shape
A so-called methylation test (a special genetic test) provides clarity. Only a few milliliters of blood from the newborn are required for this, which are then examined in the laboratory. The diagnosis is usually made in the first week of life.
Prenatal diagnostics
Since 1993, Prader-Willi syndrome can be diagnosed early in pregnancy using prenatal diagnostics. Such an examination is usually carried out in the last trimester when reduced movement of the child or stunted growth is suspected. Even if, for example, a case is already known in the family, prenatal examinations can be arranged.
Therapy: How is Prader-Willi syndrome treated?
Prader-Willi syndrome cannot be cured, but the lives of sufferers can be significantly improved through a variety of therapies and measures:
Hormone therapy
For several years, growth hormone administration has been started in infancy. This primarily benefits the physical development of people with PWS. Studies also indicate that the early start of therapy has a positive effect on behavioral disorders, language development and sleep quality. Treatment is usually continued into adulthood, when those affected receive a reduced dose.
As with other drug therapies, side effects are possible when taking hormones. These include, for example, water retention on the feet or shortness of breath. Regular medical check-ups are necessary to monitor the progress of the treatment and to identify side effects.
nutrition
A major challenge with PWS is the often insatiable appetite of those affected. In order to avoid obesity and consequential damage such as diabetes mellitus, children must learn how to deal with food at an early age. People with Prader-Willi syndrome are often very imaginative when it comes to getting hold of food. Parents should therefore strictly control food intake and, for example, close the fridge.
A reduced-calorie, balanced diet and sufficient exercise are recommended. Since patients with PWS are often less active, it can be helpful to offer them varied activities such as horseback riding or swimming. Parents should seek help from a nutritionist who specializes in children with PWS, who regularly monitors body mass index (BMI) and can offer tips on how to manage the binge eating.
psychological promotion
Many children with PWS have behavioral problems and intellectual disabilities. Therefore, early educational and psychological support for children and parents can also be helpful. Behavioral therapy measures have proven effective in getting anger outbursts and emotional behavior under control. In addition, social skills should be trained with children of the same age.
Surgical and physiotherapeutic treatments
Some people with PWS have a curvature of the spine (scoliosis) that requires orthopedic treatment. Possible misalignments of the eyes (squinting) can usually be treated well with ophthalmology. In addition, underdevelopment of the sexual organs may require surgical intervention.
Physiotherapy is often recommended. In children under the age of three, targeted muscle building can help to improve physical development. For older children, daily exercise is important to maintain a healthy body mass index.
Living with Prader-Willi Syndrome
Provided a healthy weight is maintained and there are no additional diseases such as diabetes mellitus, people with PWS now have a similarly high quality of life as healthy people.
Many people with PWS require intensive care throughout their lives. But that doesn’t mean that they can’t develop and live independently. For example, there are special pedagogical-psychological care facilities for adults with Prader-Willi syndrome. Special attention is also paid to the diet of the residents.
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