Prader-Willi syndrome (PWS) is a rare genetic disorder that affects both boys and girls. It is estimated to occur in approximately one out of every 15000 to 25000 live births.
24PWS is caused by abnormal changes in DNA sequence on chromosome.
24 In most cases, these genetic changes occur randomly and are not inherited from parents. PWS can be passed on from one generation to the next, but this is uncommon (less than 3%).
25Affected infants typically have a ‘floppy’ body and poor muscle tone (hypotonia). They have poor sucking and swallowing reflexes, which cause feeding difficulties and growth failure.
24 The hypotonia improves over time but residual weakness may persist into adulthood.
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The early period of growth failure during early infancy is followed by increased appetite, excessive eating and rapid weight gain in later childhood. Children with PWS develop an increased interest in food and gradually become obese as a consequence to obsessive eating. There is poor linear growth despite excessive calorie intake.
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Growth hormone insufficiency is common in PWS.
25 Children with PWS are likely to be of short stature, have small hands and feet without growth hormone replacement. Excess body fat is distributed mainly around the abdomen, hips, and thighs. A lack of a pubertal growth spurt results in significantly short adult height.
26Diagnosis of PWS is based on specific clinical features and confirmed by genetic testing.
25Growth hormone therapy is indicated for growth failure in PWS.
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