Idiopathic short stature (ISS) Overview ISS is a term used to cover a wide range of conditions that are associated with short stature. Idiopathic generally refers to a condition which arises spontaneously or for which the cause is unknown. These conditions are difficult to diagnose and are often caused by unknown genetic factors. Cause ISS can be caused by mutations to genes involved in the function of growth hormones and growth plate physiology; however, many causes are still unknown. Symptoms The symptoms of ISS can vary greatly. The main sign of ISS is reduced growth and short stature. Diagnosis To diagnose ISS, the healthcare professional will need to rule out other recognisable causes of short stature. This complex diagnosis includes a thorough history and physical examination, growth calculations, assessment of bone age, and eventually some laboratory investigations. In the future, as more cases of ISS are identified, we will understand more about the causes of the disorder and diagnosis may become easier. 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 Prader-Willi syndrome (PWS)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. Silver-Russell syndrome (SRS)SRS or Russell-Silver Syndrome (RSS) as it is sometimes called, is a rare genetic growth disorder. Children are generally born smaller than expected with distinct facial features. Sometimes different parts of the body will grow at different rates. Children with SRS will not catch-up to normal height in the first 2 years of life, and will need treatment early on.