Prader-Willi Syndrome / Prader-Labhart-Willi Syndrome


Prader-Willi syndrome occurs due to abnormalities of chromosome 15.

Prader-Willi Syndrome (PWS) is a rare genetic disorder affecting multiple body systems. It is consequence of an abnormality in chromosome 15, which leads to a disorder of the hypothalamus, a part of the brain. The hypothalamus is responsible for various functions linking the nervous and endocrine system. It controls hunger, thirst, body temperature, sleep, behavioral aspects, fatigue and regulates release of hormones that prompt to release other substances responsible for growth.

Major clinical manifestations include hypotonia (lack of muscle tone), poor weight gain, poor reflexes including sucking reflex, and lack of appetite during infancy. In the later years, the affected individual shows other clinical features such as overeating resulting obesity, short stature with small hands and feet, almond-shaped eyes, small mouth, impaired sexual development, hormonal insufficiency, behavioral disturbances and learning difficulties affecting normal activities of the individual.

Incidence of this rare genetic disorder is found to be 1 in 30,000 live births. It affects both males and females equally. Deaths occur due to complications associated with obesity.

Early diagnosis of PWS in children is essential to allow interventional treatment to control food intake and increase physical activity. Physical examination, complete patient history and blood tests, DNA analysis and neuroimaging studies help to detect the disease.


Treatment is symptomatic and supportive. Growth hormone therapy and appropriate care help individuals to lead a normal life, although there is no cure for this disease.

Prader-Willi syndrome should be differentiated from another syndrome due to a problem in chromosome 15. This syndrome called Angelman syndrome (AS) is a rare genetic neurological disorder characterized by severe developmental delays and learning disabilities. The patients lack speech skills and show an inability to coordinate movements. They shoe a characteristic behavioral pattern with a happy disposition and unprovoked episodes of laughter and smiling, often at inappropriate times. Additional symptoms include seizures, sleeping disorders and feeding difficulties. Some affected children may have distinctive facial features.

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