Prader-Willi syndrome is a chromosomal deletion syndrome in which part of chromosome 15 is missing or malfunctioning.
(See also Overview of Chromosome and Gene Disorders.)
About 70% of people who have Prader-Willi syndrome are missing part of chromosome 15. About 30% of people who have this syndrome have problems with the function of chromosome 15.
Symptoms of Prader-Willi Syndrome
Many symptoms of Prader-Willi syndrome vary according to the child's age.
Newborns with the syndrome feel limp, feed poorly, and gain weight slowly. Eventually these symptoms resolve.
Then, between the ages of 1 and 6, appetite increases, often becoming insatiable. Children rapidly gain weight. The hands and feet remain small, and children remain short. Abnormalities of the face include almond-shaped eyes and a mouth with thin upper lips and down-turned corners. Children have bone disorders (such as scoliosis and kyphosis).
Obsessive-compulsive behaviors and intellectual disability are common.
Hormonal problems are common, and the function of the reproductive organs is abnormally decreased, which limits growth and sexual development. Boys have undescended testes (cryptorchidism) and an underdeveloped penis and scrotum.
Weight gain often continues into adulthood and is excessive, which can lead to other health problems, such as obesity. Obesity can be severe enough to justify gastric bypass surgery.
Diagnosis of Prader-Willi Syndrome
Chromosomal testing
The diagnosis of Prader-Willi syndrome may be suspected before birth or by the child's physical characteristics after birth.
The diagnosis can be confirmed by chromosomal testing. (See also Next-generation sequencing technologies.)
Treatment of Prader-Willi Syndrome
Sometimes growth hormone
Many research studies show that human growth hormone is beneficial.
Ongoing research is being done to find treatments that help improve the prognosis for children and adults who have Prader-Willi syndrome.
