What is PWS?

Prader-Willi Syndrome (PWS) is the most common known genetic cause of life-threatening obesity in children. It is a complex genetic disorder most commonly related to problems along chromosome 15. The genes lacking in people with Prader-Willi Syndrome have a major role in the regulation of appetite and metabolic levels, cognitive functions and behavior patterns.

PWS is a complex disorder. It occurs in all races and sexes. Swiss doctors Prader, Willi and Labhart published a study of floppy babies with certain characteristics in 1956. Following the usual practice of identification, the syndrome was named for the researchers.

It has been described as a two-stage syndrome where the first, or "failure to thrive" stage, weight gain is slow and developmental milestones (both physical and intellectual) are delayed. The baby tends to be "floppy" due to low muscle tone. The second stage, "thriving too well" emerges as muscle tone improves. A compulsion to eat and an obsession with food usually appears between the ages of two and four, but sometimes later. Without environmental controls, serious weight gain occurs in 95% of the children. As this second stage evolves, behaviours such as stubbornness and mood change as well as tantrums may become evident.

Although the following statement by PWS research pioneer Dr. Hans Zellweger objectively expresses the seriousness of the syndrome, it is important that parents and families realise that not all the characteristics are predominant in each child. If, as a parent, you are reading this, your child will be himself/herself first and foremost; some of the characteristic behaviours will occur, and some won't. Careful management from parents, caregivers and families will lessen the extremes.

Dr Zellweger states: I have reached the conclusion that PWS is one of the two most grave ailments I have encountered, the other being Huntington's Disease (HD....PWS is a devastating birth defect that characteristically presents major problems from birth....PWS children constantly appear plagued by a relentless hunger that dominates their lives. The presence of this insatiable urge to eat, which is beyond the control of the patient, his family, or physician, becomes the primary focus for the child and inhibits all other activities and interest.... Parents, usually unable to manage diets, food-seeking activities, and bizarre behavior, become distraught and emotionally drained. Family systems deteriorate and life becomes hell for all concerned.

The key to understanding PWS lies in the good management of the child, a clear understanding of the syndrome, and the ability to control the environment (locked cupboards, cabinets, fridges - at home, at school, on holiday).

The two hallmark characteristics of Prader-Willi Syndrome are:

• Extraordinarily weak muscle tone
• Chronic, insatiable feeling of hunger.

These two factors lead to excessive eating and life threatening obesity. In addition, the genetic condition typically causes low muscle tone, cognitive disabilities, incomplete sexual development, obsessive compulsive disorder and problem behaviors.

PWS causes organic damage to the hypothalamus, which controls appetite and metabolism. It also causes damage to other areas of the brain that control cognition and behavior. This damage is irreversible and there is no cure. However, good medical intervention such as growth hormone treatment, and anxiety-reducing medication, can help with good physical growth which encourages the child's ability to be more active and able, while anxiety-reducing medication can help alleviate worries and concerns and therefore reduce challenging behaviours, tempers, and outbursts. Good behavioural management techniques are imperative and should be used by all who work with, live with, or teach people with PWS.

The incidence rate of Prader-Willi Syndrome is estimated to be one in 10,000 to 25,000. Outlined below is a description of Prader-Willi Syndrome.

The Infant

 

Typically born pre-mature, and 'floppy', with low-birth weight, newborns quickly experience "failure to thrive". Failure to thrive can claim an infant's life if it is not responded to rapidly and appropriately by attending medical staff. Infants spend the first few weeks of life in neo-natal intensive care units and are discharged home with complicated instructions. Because of the inability to properly suck from a nipple, most infants cannot breast feed or take food from a bottle. Tube feeding is generally required for several weeks or even months. Respiratory problems require apnea monitors and oxygen therapy.

The Child

Developmental delays in the toddler require constant occupational, physical and speech therapies. At approximately two years of age a child with the syndrome begins to develop an insatiable appetite. The child will continue his/her drive to eat and seek food regardless of the amount consumed. This drive is not satiated with food. Unless some type of significant intervention is provided, such as strict management of food intake, an exercise programme, restricted access to food, the child will become extremely obese. The two following medical record excerpts illustrate the suffering caused by PWS:

 

• Four years old, weighing 95 pounds is in ICU on "deaths doorstep." The obesity has caused upper airway restriction and an enlarged heart.
• Mother found her three-year-old daughter dead. The autopsy revealed she had PWS. Death was due to weight related obstructive sleep apnea and a fatty liver.

The Adolescent

 

Without intervention, extreme obesity leads to life threatening health problems and social ridicule in the older child.

 

For the parents, survival often becomes the name of the game. Kitchens are locked tight and guarded with vigilance. Mealtimes are a constant struggle where desserts are unheard of and the child with PWS intently watches everything his/her parents and siblings eat. Meals often end with the inevitable, "It's not fair...!" and the beginning of a tantrum.

Equally significant are the emotional issues that arise, particularly as the child ages into adolescence. Such problems as emotional outbursts and temper tantrums increasingly alienate the child from their family and peers. In addition, the child with Prader-Willi usually has speech and communication difficulties that increase their frustration and contribute to social withdrawal.

The Adult

Largely due to a lack of appetite control and behavioral problems, adults with Prader-Willi Syndrome are unable to live independent lives. Holding down jobs, even with the constant supervision of one-to-one aides, becomes impossible. The runaway appetite and resulting behavior and social issues mean an adult with PWS needs a lifetime of controlled environments and activities. In comparison to the cost of caring for, and supervising, persons with all disabilities, the annual cost of care and supervision of an individual with PWS is among the highest, between USD75,000 and USD150,000 per year. The high cost of PWS care is due to the unique nature of the behavioral problems and appetite control issues. The following case reports highlight the need for extreme levels of supervision and care:

• A young man, 25 years old, who had been a poster person of PWS success, recently died from complications of a ruptured stomach. He had gone to a baseball game with the staff from his group home and excused himself to go to the bathroom. Using money he had stolen, he bought and consumed a huge amount of food before returning to his seat. Later that night after complaining of stomach pain he was admitted to the hospital and died hours later.
• A 33 year-old, 390 pound man was hospitalized after swallowing a potato whole. He was trying to sneak food and was afraid he would be caught. The potato was surgically removed, the young man remained on a respirator for four days before he died.

Only with constant care and supervision from infancy and early childhood through adult life can a person with Prader-Willi Syndrome avoid a lifetime of chronic health, social crises and premature death. Based upon a review of PWS-related deaths by the Prader-Willi Syndrome Association (USA) for the years 2001 through 2003, the average age of death was 27-years-old. With the correct care and management around food and social structures, a person with PWS can live a normal life-span.