What is Prader-Willi syndrome?
Prader-Willi syndrome (PWS) is a rare syndrome caused by a defect in the genetic make-up. It occurs worldwide at about 1-9 per 100,000 births. Both boys and girls can be affected by Prader-Willi syndrome. Those affected are small in stature, already have low muscle tone as newborns and suffer from obesity later in life. Mental abnormalities and a reduction in intelligence are also characteristic of Prader-Willi syndrome.
Causes
The cause of the Prader-Willi syndrome is a so-called “paternal deletion”. This means that on chromosome 15, inherited from the father, a piece of the genetic information is deleted and is now missing. In most cases, this deletion occurs spontaneously (new mutation) and is not inherited.
It is suspected that this change in the genetic material leads to a malfunction of the hypothalamus (part of the midbrain). The hypothalamus is an important control center of the body, which is also responsible for the release of many hormones. In Prader-Willi syndrome, among other things, too little growth hormone is secreted, which leads to dwarfism.
Diagnosis
The suspicion of a Prader-Willi syndrome can be raised by the pediatrician in charge shortly after birth. The newborns are conspicuous by muscular weakness, weakness in drinking and weakly developed newborn reflexes. When determining the hormone levels in the blood, lowered values for the growth and sex hormones are noticeable. The confirmation of the diagnosis can only be provided by a genetic examination. Here the deletion on chromosome 15 is detected.
By these symptoms you recognize Prader-Willi syndrome?
Affected children are already noticeable immediately after birth because they have low muscle tension (“floppy infant”), are particularly small and light and do not drink properly. Children with Prader-Willi syndrome have a characteristic appearance: almond-shaped eyes, a thin upper lip, a narrow nose root and small hands and feet. Often affected children also squint.
In boys, a small scrotum is noticeable at an early age and there is often an undescended testicle. Child development is delayed and milestones in development such as walking and talking are reached later. From about the age of three, affected children develop an uncontrollable appetite without a feeling of fullness when eating.
This pathologically increased appetite leads to obesity. Overweight can be accompanied by secondary diseases such as diabetes, sleep disorders and cardiovascular diseases. The reduced release of growth hormones also prevents a growth spurt during puberty.
The genitals also remain underdeveloped. Prader-Willi patients usually remain infertile. Typical for a Prader-Willi syndrome are also reduced intelligence and learning difficulties. Psychological abnormalities such as impulse control disorders and mood swings also occur frequently in those affected.