Prader-Willi syndrome (PWS) Overview PWS is a rare genetic disorder in which a part of the brain known as the hypothalamus doesn’t develop as expected. PWS is associated with a number of issues including short stature, difficulties with behavioural and social skills, and distinct facial features. PWS affects about 1 in 20,000 children. Cause The cause of PWS is genetic and it can also affect a number of hormonal processes. A few different genes are affected, leading to a number of health issues. In nearly 80% of PWS cases, the body may not produce enough growth hormone leading to short stature. Symptoms In PWS a few different genes are affected, therefore symptoms can be quite varied. Some symptoms include short stature, affected infant social skills, distinct facial features, learning disabilities, behavioural and psychiatric problems, late puberty and obesity. Diagnosis Diagnosis can be made in the first few months of a baby’s life, allowing early care and treatment. Genetic testing can be used to check the chromosomes in the child’s blood sample. As well as confirming the diagnosis, the results may also determine the likelihood of having another child with the syndrome. Growth calculator It is important to keep track of your child’s growth in order to identify if there is a problem early on. We recommend measuring your child every 6 months, which is now easier, with our simple to use growth calculator. Calculate your child’s growth Talking to your doctor about child growth If you are concerned about your own or your child’s growth, you should speak to a doctor. This section will help you with what questions to ask, so that you can be prepared. Get prepared Related Familial short statureChildren with familial short stature tend to fall at the lower extreme of the growth chart (below the 3rd percentile) and their growth is usually impacted by their parents’ heights. This does not tend to impact their overall health and their height is generally considered to be appropriate for their genetic potential based on their parents’ heights. HypothyroidismHypothyroidism occurs when the thyroid gland does not produce enough thyroid hormone, which can result in slowing down of the body processes. In children this can mean slower growth and delayed puberty. Hypothyroidism in children is generally quite rare.