Prader Willi Syndrome

Prader Willi Syndrome

prader willi syndrome
prader willi syndrome

What is Prader Willi Syndrome?

This medical condition is a rare genetic disorder. It is also called chromosome 15 disorder. It was discovered in 1956 by a group of scientists, Andrew Ziegler, Heinrich Willi, Gudio Fanconi, Andrea Prader, and Alexis Labhart. It is so rare that only one in fifteen to sixteen thousand people worldwide are born with it. It can affect all races and equally occurs in males and females. Although this is a rare genetic disorder, it is one of more common ones known that can cause life-threatening obesity.


Some of the symptoms of this syndrome are caused by abnormal function of the hypothalamus gland that controls the functions of thirst, hunger, and also releases the hormones that are responsible for sexual and growth development. The symptoms of Prader-Willi Syndrome will normally occur in two different stages.

During the first year of life

  • Having poor muscle tone called hypotonia. They may rest with their knees and elbows loosely extended instead of the normal way which is fixed. They may also feel floppy when you hold them.
  • They have distinct facial features such as being born with eyes that are almond shaped, a thin upper lip, narrowing of the head at the temples, and a mouth that is turned down.
  • Having lack of eye coordination called strabismus, which means that their eyes may not move together and instead wander to the side or cross.
  • They generally will have poor responsiveness such as seeming to be unusually tired, they are difficult to wake up, have a weak cry, or respond to stimulation poorly.
  • Have a low birth weight
  • Having difficulty sucking, whether breast feeding or using a bottle.

During early childhood

This time frame normally refers to children from the ages of one to four but can be later. In this age group the problems will be there throughout their life and will require careful treatment and management. These symptoms can include:

  • There is a constant craving for food resulting in rapid weight gain, which is a classic symptom of Prader-Willi Syndrome. This is called hyperphagia. A child with this disorder is always hungry and last their entire lifetime. They want to eat continually and eat large portions at a time. They may also start to develop strange food seeking behaviors such as eating frozen food or garbage and even hoarding food.
  • They have a metabolism that will drastically use fewer calories than normal.
  • Their sexual organs are underdeveloped. This symptom/condition is called hypogonadism. The ovaries in women and the testes in men produce little to no sexual hormones. Their development at puberty is incomplete and nearly all with this syndrome are infertile. Some women may never menstruate or not start until they are in their thirties. Some men may never have voices that deepen fully and may not have much facial hair.
  • Poor physical development and growth. They have low muscle mass, short feet and hands, and are usually shorter than other members of the family when they reach full adulthood.
  • They may have mild to moderate leaning disabilities with cognitive impairment one of the common learning disabilities. The average IQ for a child with this syndrome is seventy.
  • They will have delayed motor development which means that they reach physical movement milestones later than normal children. For example sitting up by themselves may be delayed until they are a year old and not walking until they are two years old.
  • Speech can be delayed until they are two years of age and they still may always have poor articulation of words.
  • They have behavioral problems such as throwing temper tantrums and being extremely stubborn, especially when they are not given food. They may also have obsessive-compulsive behavior, rectal gouging, or skin picking.
  • Some will have sleep disorders that include sleep apnea or disruptions of a normal sleep cycle,
  • Developing an abnormal curvature of the spine called scoliosis.

Other Symptoms

  • Being nearsighted also known as myopia.
  • Their skin may be lighter than other members of the family.
  • They may have a high tolerance of pain.


The cause of Prader-Willi Syndrome is due to seven genes on the chromosome 15 are missing, unexpressed, or deleted on the paternal chromosome, which comes from the father. One of the reasons that the gene is unexpressed is that the child inherited no chromosome 15 from the father and instead received two chromosomes 15 from the mother. The genetic defect also disrupts the normal functioning of your hypothalamus gland. Although this is a genetic disorder, it is not hereditary but if a mother has one child with this disorder there is a greater chance of her having another child with it.


The main way to diagnosis Prader-Willi Syndrome is by using genetic testing. A diagnosis can be made by a physician based on the clinical symptoms. Sometimes a doctor will suspect Prader-Willi Syndrome if the infant is born with significant muscle weakness and appears to be very floppy when held. They can also us the mental behavior, condition, and physical characteristics of a child to see if they are consistent with Prader-Willi Syndrome. In order to actually confirm the diagnosis the physician will order a blood test done called a methylation analysis. With this test they are able to detect ninety-nine percent of the cases. This test is especially important for the diagnosis of children who are young and have not displayed sufficient features and characteristics to make a diagnosis based on clinical observation.


There is no cure for Prader-Willi Syndrome but children with this genetic disorder will need to have the following treatments and care:

  • As an infant they will need to have good nutrition. Infants with this syndrome often have trouble feed because their muscle tone has decreased. Your infant may be given a high calorie formula to help them gain weight. Their development will also be monitored.
  • They may be given growth hormone treatment to influence their body to convert food into energy and to stimulate growth. Some studies suggest that using growth hormone treatment can also help to improve their muscle tome and help to decrease the amount of body fat.
  • Use sexual hormone treatment such as hormone replacement therapy. This would be progesterone and estrogen for the women and testosterone for males to help replenish their low levels of sexual hormones. It can also help to decrease the child’s risk of developing osteoporosis, or thinning of the bones.
  • Making sure that the child is eating a healthy reduced calorie diet to help keep their weight under control.
  • Their overall development will be watched by a variety of doctors and therapists including speech therapists to help improve their verbal skills, physical therapists to help improve their strength and motor skills, and others.
  • Mental health care workers such as a psychiatrist or psychologist to help the child if they have a mood disorder or obsessive compulsive disorder. Some may need medication to help control their behavioral problems.
  • Because most of these children are obese and may have sleep apnea, they may need a machine that will help them breathe while they sleep.

In addition, if the syndrome is diagnosed in a newborn treatment mentioned above can be started early to help control and lessen various aspects of this disease.

Life Expectancy

There is no definite answer as to how long a child with Prader-Willi Syndrome will live because there are many factors that can figure in to whether he lives a long life or dies young. If they follow a healthy diet and keep their weight under control they will live a long life. If they do not and become obese because of the uncontrolled hunger they could develop lung problems and heart failure resulting in dying young.

Prader Willi Syndrome Pictures

Photos, Images and Pictures of Prader Willi Syndrome…

prader willi syndrome

prader willi syndrome pictures

prader willi syndrome pictures 2

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