Prader-Willi syndrome is a genetic disorder that causes mental and physical impairments and leads to abnormal eating behavior. The disorder is rare and affects both men and women.
What is Prader-Willi syndrome?
Prader-Willi syndrome (PWS) is a genetic disorder that occurs in both men and women. It is caused by a gene defect on chromosome number 15. The altered gene causes mental and physical disability as well as metabolic disorders. A particular hallmark of Prader-Willi syndrome is an uncontrollable desire to eat, which leads to marked obesity in patients. The disorder was named after Swiss physicians Andrea Prader and Heinrich Willi, who first described the symptoms in 1956. The chromosome on which the triggering genetic defect is located was found in 1981. Prader-Willi syndrome occurs rarely, and it is estimated that about 350,000 people worldwide are affected.
Causes
The cause of Prader-Willi syndrome is a mutation of chromosome 15. Here, there are three different variants, but they all lead to the same symptoms. In 70% of the cases the cause is the absence (deletion) of a part of the paternal chromosome 15. In about 29% the chromosome 15 is present in double version from the mother, instead of once from the father and once from the mother as normally. The third very rare variant is a special mutation called an imprinting defect. The gene alteration causes hormone release in the hypothalamus not to occur regularly. The resulting undersupply of hormones causes the physical and mental disorders.
Symptoms, complaints, and signs
Typical symptoms of Prader-Willi syndrome include congenital muscle weakness (muscle hypotonia). In this case, the basic tension of the skeletal muscles is lower than in other people. Affected individuals are also often less sensitive to pain than other individuals. The mental and physical developmental level of affected individuals is below what would be expected given their age. Prader-Willi syndrome is associated with moderate intellectual disability. At this level of mental retardation, the mental age is between six and nine years. This corresponds to an IQ of 35 and 49. For comparison, an IQ of 85 to 115 is considered normal. Another characteristic of Prader-Willi syndrome is an increased appetite and a disturbed feeling of satiety. Affected individuals often eat more than they need. Both continuous eating and binge eating are possible. As a result, most people with Prader-Willi syndrome are overweight or obese. Obesity often develops in early childhood. Diabetes (diabetes) is another possible symptom of Prader-Willi syndrome. Affected individuals typically suffer from an underactive gonad (hypogonadism). As a result, they may be infertile. Outward signs of Prader-Willi syndrome include almond-shaped eyes and a triangular mouth area. Hands and feet are often unusually small – short stature also occurs. Visual disturbances are also part of the symptoms in many cases. Nearsightedness and strabismus, or squinting, are particularly common.
Diagnosis and course
The symptoms of Prader-Willi syndrome vary from case to case. Some children are already conspicuous as unborn babies during pregnancy because of a lack of activity. As infants, they drink little and have flabby muscles. The children have almond-shaped eyes and a triangular mouth part, they suffer from vision problems, often they are short-sighted or squint. The hands and feet are smaller than normal, and the overall height is also below average because too little growth hormone is produced in Prader-Willi syndrome. The sexual organs are underdeveloped, and boys often have undescended testicles. Puberty is delayed, sex characteristics are poorly developed, and most affected individuals are infertile. Mental retardation may exist. Later in life, at about three years of age, uncontrollable binge eating begins to develop. The children eat everything they can find, including scraps. Diagnosis is made on the basis of symptoms, as well as through various examinations, such as hormone determination in the blood and examination of the thyroid gland.A genetic test can reliably detect whether Prader-Willi syndrome is present.
Complications
The complications to be expected in Prader-Willi syndrome are primarily due to the severe obesity from which affected individuals almost always suffer, as well as the consequences of metabolic diseases, especially diabetes mellitus. The often very high overweight can also cause severe orthopedic damage. Early orthopedic damage to the lower extremities is already observed in children. In particular, the weight-bearing joints of the lower extremities, i.e. hip, knee and ankle joints, as well as the feet, often show signs of overload and wear due to obesity. Life-threatening complications can be expected in Prader-Willi syndrome, especially when the great excess weight leads to damage to the blood vessels and internal organs. In addition, because patients suffering from Prader-Willi syndrome do not have a sense of satiety, there is a risk that they will overstretch the stomach until it ruptures. This risk is increased by the fact that sufferers do not vomit or experience fullness or pain when they overeat. Also, the rupture of the stomach often goes unnoticed at first. Patients therefore run the risk of bleeding internally as a result of the gastric rupture. Furthermore, in patients suffering from Prader-Willi syndrome, sleep apnea syndrome can be life-threatening. Sleep apnea is a condition in which sufferers experience cessations of breathing during sleep.
When should you see a doctor?
Babies with Prader-Willi syndrome need a lot of support during and after birth. Parents should consult directly with the doctor in charge so that the necessary examinations and treatments can be given early. Depending on the severity of the condition and the number and severity of the malformations, regular visits to the doctor may be necessary thereafter. If unusual symptoms occur, such as fever, swallowing difficulties or visual problems, the relevant specialist must be consulted. In addition to the pediatrician, internists, surgeons, ophthalmologists, ENT specialists and other specialists may also be called in, depending on the symptoms. The affected child also needs physiotherapeutic support. In the case of severe malformations, a rehabilitation measure is already necessary in the first years of life, which is usually carried out with the mother and the child. If the complaints become more severe, a visit to the pediatrician is necessary. If an accident or fall occurs as a result of the deformities, it is best to call the emergency doctor. Psychological counseling is offered if the condition has a negative effect on the mental state of the child or the relatives.
Treatment and therapy
Treatment of Prader-Willi syndrome is based on the symptoms. Because there is decreased hormone secretion in the condition, hormone replacement therapy is given. The earlier hormone administration is started, the better the symptoms can be alleviated. Children with Prader-Willi syndrome usually require comprehensive care and special support. Weight must be reduced and food intake controlled. Edibles must be literally locked away, as patients with Prader-Willi syndrome will eat anything they can find, whether it is edible or not. This means they also eat animal food, garbage or frozen food. In most cases, many symptoms improve as patients lose weight. Behavioral therapy can be supportive in maintaining the diet. Physical therapy helps improve muscle tone and counteract slack muscles. Speech therapy supports the ability to speak. Eye problems usually require ophthalmologic treatment, and vision should be checked regularly. The children need mental support, possibly attendance of special schools is necessary. Sometimes, in the further course of Prader-Willi syndrome, heart problems and a spinal curvature develop, caused by extreme overweight. In this case, orthopedic and internal therapy is necessary in addition to weight reduction.
Prevention
Prader-Willi syndrome cannot be prevented because it is genetic. Early diagnosis and rapid onset of therapy are important to prevent serious sequelae caused by Prader-Willi syndrome.
Follow-up
Prader-Willi syndrome is a genetic chronic disease that cannot be cured.Medical treatment is only purely symptomatic. Therefore, follow-up care in the classical sense is not possible. However, affected children and adults with Prader-Willi syndrome are affected by life-threatening obesity and other health complaints throughout their lives. For this reason, regular check-ups and intensive dietary care are necessary. These measures are usually ordered and monitored by a pediatrician or general practitioner. First and foremost, the body weight of the affected children or adults is checked. In addition, regular blood tests are common. Sometimes urine or stool samples or other tests are also required. The attending physician decides on the frequency of the check-ups and the necessary follow-up measures. In many cases, affected patients are placed in specialized long-term care facilities that include medical care. Apart from this, in most cases inpatient stays in rehabilitation clinics are necessary in order to develop a therapy concept suitable for the patient. In the course of such placements, at least one to two medical examinations per week are common. Further therapeutic measures may be necessary in the course of obesity therapy.
What you can do yourself
Children who have Prader-Willi syndrome need ongoing support in their daily lives. Relatives should consult a nutritionist and work with him or her to create a diet that matches the child’s eating habits. Accompanying behavioral therapy may be necessary. The child should also not have access to potentially harmful foods, waste, or inedible products. If the child has consumed something inappropriate, the emergency physician should be called. To counteract the child’s usually high level of emotion, sports and an open approach are suitable measures to accompany medical treatment. It is important for the child to have a regular daily routine from which no deviation is allowed. It is advisable to draw up a long-term plan to enable the child to lead as stable a life as possible without sudden changes in everyday life. Sick children need a lot of attention and place great physical and mental demands on their parents. This makes phases of rest and relaxation all the more important for relatives and acquaintances who are caring for the child. A therapist can help create space and work through emotional conflicts. The parent or guardian should keep in close contact with the doctors and inform them of any unusual symptoms. A comprehensive therapy approach can help people suffering from Prader-Willi syndrome lead relatively symptom-free lives.
