Parder-Willi Syndrome

by:Lo Martinez 1B

Prader-Willi Syndrome

Prader-Willi syndrome is a complex genetic condition that affects many parts of the body. In infancy, this condition is characterized by weak muscle tone (hypotonia), feeding difficulties, poor growth, and delayed development. Beginning in childhood, affected individuals develop an insatiable appetite, which leads to chronic overeating (hyperphagia) and obesity. Some people with Prader-Willi syndrome, particularly those with obesity, also develop type 2 diabetes mellitus (the most common form of diabetes).

People with Prader-Willi syndrome typically have mild to moderate intellectual impairment and learning disabilities. Behavioral problems are common, including temper outbursts, stubbornness, and compulsive behavior such as picking at the skin. Many affected individuals also have sleep abnormalities. Additional features of this condition include distinctive facial features (such as a narrow forehead, almond-shaped eyes, and a triangular mouth), short stature, and small hands and feet. Some people with Prader-Willi syndrome have unusually fair skin and light-colored hair. Both affected males and affected females have underdeveloped genitals. Puberty is delayed or incomplete, and most affected individuals are unable to have children

is it hereditary? what are the symptoms? how long do you live?

1.Prader-Willi syndrome affects an estimated 1 in 10,000 to 30,000 people worldwide. Most cases of Prader-Willi syndrome are not inherited, particularly those caused by a deletion in the paternal chromosome 15 or by maternal uniparental disomy. These genetic changes occur as random events during the formation of reproductive cells (eggs and sperm) or in early embryonic development. Affected people typically have no history of the disorder in their family.

2.Consensus clinical diagnostic criteria are accurate, but the mainstay of diagnosis is DNA methylation testing to detect abnormal parent-specific imprinting within the Prader-Willi critical region (PWCR) on chromosome 15; this testing determines whether the region is maternally inherited only (i.e., the paternally contributed region is absent) and detects more than 99% of affected individuals. DNA methylation-specific testing is important to confirm the diagnosis of PWS in all individuals, but especially in those who have atypical findings or are too young to manifest sufficient features to make the diagnosis on clinical grounds.

3.Failure to thrive in infancy may necessitate tube feeding. Infants should be closely monitored for adequate calorie intake and appropriate weight gain. Growth hormone is typically deficient, causing short stature, lack of pubertal growth spurt, and a high body fat ratio, even in those with normal weight. The need for GH therapy should be assessed in both children and adults.The life expectancy of persons with Prader-Willi syndrome (PWS) has increased in recent years but roughly the life span stretches from 18-49 years


  • Prader-Willi Syndrome (PWS) is a disorder of chromosome 15.
  • It is estimated that PWS affects one in every 12,000 – 15,000 births.
  • PWS is diagnosed through DNA analysis.
  • Newborns with PWS typically have feeding problems and difficulty gaining weight.
  • Developmental milestones typically are delayed by one to two years.
  • People with PWS are of short stature by age 15 and have small hands and feet for their age.
  • Behaviors characteristic of people with PWS include tantrums; violent outbursts; obsessive/compulsive behavior; a tendency to be argumentative, manipulative, possessive and stubborn; stealing and lying.
  • PWS puts people at greater risk for developing curvature of the spine, weakened bones, diabetes, hypertension and dental problems, among others