Prader-Willi syndrome
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What is Prader-Willi syndrome?
Prader-Willi syndrome (PWS) is a rare genetic disorder that occurs in approximately 1 of 15,000 live births. It is characterized by weak muscle tone at birth, short stature, and intellectual disabilities. Beginning between one and six years of age, children with PWS develop a tremendous interest in food and overeat, which leads to childhood obesity and high rates of morbidity and mortality. PWS arises from the deletion or disruption of genes in a particular region of chromosome 15. Though PWS is incurable, several treatments are available to alleviate the symptoms.
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What causes Prader-Willi syndrome?
Prader-Willi syndrome (PWS) is a rare genetic disorder that stems from the disruption or deletion of genes in a specific region of chromosome 15.
PWS results from mutations in imprinted genes. Maternally imprinted genes are expressed only when inherited from the father, while paternally imprinted genes are expressed only when inherited from the mother. The disease gene associated with Prader-Willi syndrome is maternally imprinted, so only the paternal copy is expressed. If the paternally inherited copy carries a mutation, the child will not have functional copies of the gene expressed, and the clinical traits of Prader-Willi syndrome will result.
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What are the main symptoms of Prader-Willi syndrome?
Prader-Willi syndrome (PWS) is a rare genetic disorder that leads to several distinctive symptoms.
Key characteristics include:
* Weak muscle tone at birth
* Small stature
* Intellectual disabilities
* Overeating, which can lead to obesity in childhoodOther common features of PWS include a narrow face, almond-shaped eyes, a small-appearing mouth, and thick saliva. Children with PWS may also have behavioral issues, such as aggressive outbursts and obsessive-compulsive disorder. Endocrine problems, like reduced sex hormones, can also occur.
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How does Prader-Willi syndrome affect a person's growth and development?
Prader-Willi syndrome (PWS) is a rare genetic disorder that impacts growth and development, resulting from the disruption of genes on chromosome 15.
PWS is characterized by weak muscle tone at birth, small stature, intellectual disabilities, and an insatiable appetite that can lead to childhood obesity and increased mortality. Children with PWS experience delays in meeting developmental milestones like walking and talking. Endocrine issues, such as reduced sex hormone secretion, are also common, which can delay puberty and result in shorter stature. Growth hormone therapy can help improve growth, strength, and agility. A balanced, low-calorie diet, along with weight monitoring and exercise, can help manage eating and weight issues.
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How is Prader-Willi syndrome diagnosed?
Prader-Willi syndrome (PWS) is a rare genetic disorder that arises from the disruption of genes on chromosome 15. Genetic tests, such as fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH), are used in diagnosing PWS because of their high rates of sensitivity and specificity. FISH can detect genetic deletions involving a few genes, while CGH is more sensitive and can detect small chromosomal rearrangements, deletions, and duplications. These procedures provide results more rapidly than traditional karyotyping because they don't require cell culture.
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What treatments and support are available for people with Prader-Willi syndrome?
Prader-Willi syndrome (PWS) is an incurable genetic disorder that causes weak muscle tone, short stature, intellectual disabilities, and overeating, which leads to obesity. However, treatments are available to alleviate the symptoms of PWS.
Available treatments:
* Growth-hormone therapy can help with short stature, linear growth, and physical strength.
* Octreotide can help with weight loss in obese children.
* Therapies are available to stimulate testosterone production in patients with hypogonadism.
* Physical therapy and exercise can help improve strength and coordination.
* Speech therapy can benefit patients with language problems.
* A balanced, low-calorie diet, weight monitoring, external food restriction, and daily exercise can help control eating and weight problems as the child grows.1 Britannica SourceCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
Prader-Willi syndrome (PWS), a rare human genetic disorder characterized by weak muscle tone at birth, small stature, intellectual disabilities, overeating leading to childhood obesity, and high rates of morbidity and mortality. PWS arises from the deletion or disruption of genes in a particular region of chromosome 15. First described in 1956 by Andrea Prader, Heinrich Willi, and others, it occurs in approximately 1 of 15,000 live births.
Mothers with prior experience of normal pregnancies report distinctly delayed onset of labour and reduced fetal activity during the pregnancies involving Prader-Willi children. PWS is characterized at birth by the lack of spontaneous movements, excessive daytime sleepiness, and protective reflexes. Babies display little interest in feeding, and their ability to suck is weak or absent. They will take longer to attain the ability to walk, talk, sit, and stand. Children will go on to develop symptoms of muscular hypotonia (weak muscle tone). Distinctive facial features also identify a child with the syndrome; these include a narrow face, almond-shaped eyes, small-appearing mouth, a thin upper lip with down-turned corners of the mouth, and full cheeks. The child’s eyes may cross (strabismus). A frequent feature generally overlooked is thick saliva at the edges of the mouth. Patients also tend to be relatively insensitive to pain.
Between ages one and six, children with PWS suddenly develop a tremendous interest in food and begin overeating (hyperphagia). Dysfunction in the brain regions associated with satiety and hunger leads to severe disturbances of appetite regulation, including delayed meal termination and early return of hunger after a meal, resulting in abnormal body mass composition and obesity; this in turn leads to increased cardiovascular morbidity and mortality. Some obese PWS patients eventually are diagnosed with type 2 diabetes, of which obesity is a common cause.
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PWS children commonly exhibit behavioral problems. In some cases, for example, affected children display spontaneous outbursts of aggressive behaviour. PWS has also been associated with obsessive-compulsive disorder and sleep abnormalities. Patients may develop other behavioral difficulties as well as intellectual disabilities and other cognitive and learning problems.
Children with PWS also have endocrine problems including reduced or absent secretion of sex hormones (hypogonadism). During adolescence, males may have a smaller penis and undescended testis. Secondary sexual characteristics such as pubic hair and breast development in females may not develop as well. Growth spurt is also delayed, and thus patients tend to have a shorter stature.
PWS is incurable; however, several treatments are available to alleviate the symptoms. Growth-hormone therapy for short stature improves body composition, linear growth, physical strength, and agility. Treatment with octreotide, a somatostatic agent, can induce weight loss in children with obesity. Other therapies can stimulate testosterone production and virilization in patients with hypogonadism. Physical therapy and exercise help improve strength and coordination. Speech therapy is often beneficial for patients with language problems. As the child grows, eating and weight problems can be controlled through a balanced low-calorie diet, weight monitoring, external food restriction, and daily exercise.