Health A to Z
Restricted growth, sometimes known as dwarfism, is a condition characterised by short stature.
There are two main types of restricted growth:
As well as having short stature, some people with restricted growth also have other physical problems, such as bowed legs or an unusually curved spine.
However, most people don't have any other serious problems. They can often live a relatively normal life and have a normal life expectancy.
Read more about the symptoms of restricted growth.
The most common cause of PSS is being born to small parents, but it can sometimes occur as a result of the body not producing enough growth hormone.
DSS usually occurs as part of a genetic condition, such as achondroplasia. Many children born with DSS have parents of average height and the faulty gene causing the condition occurred by chance.
If your child is diagnosed with restricted growth, tests will be carried out to try to identify the underlying cause.
Treatments recommended for people with restricted growth depend on the cause of the condition and any associated problems they have. A number of different healthcare professionals will usually be involved in your care.
Some people with restricted growth may benefit from treatment with growth hormone injections, which can help a child with restricted growth grow more than they otherwise would.
In cases of DSS where the legs are particularly short, a leg-lengthening procedure is sometimes used, although this is controversial and there is uncertainty about its safety and effectiveness.
Read more about treatments for restricted growth.
People with restricted growth (dwarfism) often have no symptoms other than short stature, although some people have associated health problems.
Symptoms commonly seen in people with proportionate and disproportionate short stature are outlined below.
People with proportionate short stature (PSS) grow very slowly and have a general lack of growth throughout the body. The length of the trunk (tummy and chest) remains in normal proportion with the legs.
PSS may not be noticeable until later in childhood or until a child reaches puberty.
Additional symptoms associated with PSS depend on the underlying cause. For example:
Read more about the causes of restricted growth.
In people with disproportionate short stature (DSS), there is an overall lack of growth, and certain limbs may be shorter or out of proportion with other parts of the body.
People with achondroplasia, one of the most common causes of DSS, typically have:
Most people with DSS don't have any other significant health problems, although some people with achondroplasia have:
Restricted growth (dwarfism) may be caused by many different medical conditions, and is more noticeable in some conditions than others.
The main cause of proportionate short stature (PSS) is being born to small parents.
A less common cause is the body not producing enough growth hormone, which is estimated to affect one in every 3,500 to 4,000 children.
This may be present at birth, because of problems with the pituitary gland (a pea-sized gland below the brain responsible for producing several important hormones) or as part of another condition. It can also start in childhood, as the result of an injury, a brain tumour or radiotherapy to the brain.
In about half of children with growth hormone deficiency, the cause is unknown.
Other possible causes of PSS include:
If your child is diagnosed with restricted growth, tests may be carried out to try to identify the underlying cause.
Read more about diagnosing restricted growth.
Conditions associated with disproportionate short stature (DSS) are usually caused by a faulty gene. The affected genes stop the bones and cartilage developing properly, leading to restricted growth that is often noticeable from birth.
Many children born with DSS have parents of average height and the change to the gene happens by chance. However, people with conditions that cause DSS may pass their condition on to their children.
The most common cause of DSS is a condition called achondroplasia, which is estimated to affect around one in every 25,000 people.
Other conditions that cause DSS include:
You can read more about some of these rare conditions on the Restricted Growth Association website.
A diagnosis of restricted growth (dwarfism) is based on symptoms, height measurements, family history and tests.
Depending on the cause of the condition, restricted growth may be diagnosed before or soon after a child is born, or when growth problems become more obvious as they get older.
Tests may not need to be carried out if you or your child don’t have any other health problems.
Growth hormone deficiency is usually diagnosed using growth hormone stimulation tests.
Medicine is injected into a vein to cause growth hormone levels in the blood to increase. If the level of growth hormone is found to be lower than normal, it indicates growth hormone deficiency.
A scan of the brain is necessary to look at the pituitary gland (which produces growth hormone) if blood tests show low levels of growth hormone.
The following tests can be used to diagnose a condition that causes short stature:
Diagnosis during pregnancy (also called prenatal diagnosis) may be offered to parents who have a genetic history of a condition that causes short stature.
Some potential abnormalities may be visible during routine ultrasound scans, but tests such as chorionic villus sampling or amniocentesis are needed to confirm a diagnosis, as they can be used to see if your baby carries one of the faulty genes associated with restricted growth.
Some people with restricted growth may be able to have treatment to help them grow more than they otherwise would, although not everyone will need treatment.
Support and treatment is also available to help with related problems, such as associated health conditions and difficulties with daily activities.
The National Institute for Health and Care Excellence (NICE) recommends human growth hormone treatment (somatropin) as an option for children whose poor growth is associated with:
NICE also recommends the treatment for children who are born small and fail to catch up in growth by the age of four or later.
Somatropin treatment should be started and monitored by a child health specialist (paediatric endocrinologist) with expertise in managing growth hormone disorders in children. It's given as a single daily injection, which can usually be done by a parent or carer.
Skin reactions are the most commonly reported side effect of somatropin. In very rare cases, the treatment is associated with persistent severe headaches, vomiting and vision problems.
Children with growth hormone deficiency respond very well to growth hormone treatment and may be able to reach a relatively normal adult height. The effectiveness in children with other conditions can vary.
Growth hormone treatment may stop once your child stops growing, but in some cases it may be given into adulthood because it can sometimes help prevent problems such as weak bones (osteoporosis).
For more information, read the NICE guidelines on Human growth hormone (somatropin) for the treatment of growth failure in children and Human growth hormone (somatropin) in adults with growth hormone deficiency.
If a person has particularly short legs, a leg-lengthening process, known as distraction, may be an option. This involves dividing the leg bone and fixing it to a special frame. This is gradually adjusted every day to encourage the bone to grow over time.
This can sometimes result in a significant increase in height, but it's a lengthy treatment and has a risk of complications, so it's not always recommended.
NICE says there is uncertainty about the safety and effectiveness of this procedure, so they recommend making sure you understand exactly what it involves and to talk to your surgeon or doctor about the risks if it's suggested as a treatment.
Some people have pain after the limb-lengthening procedure. Other possible complications include:
For more information, read NICE guidelines on Intramedullary distraction for lower limb lengthening.
As restricted growth can be associated with several related conditions and problems (read more about the symptoms of restricted growth), affected children and adults are likely to be cared for by a team of different healthcare professionals.
These may include:
You may have regular check-ups with members of your care team, so your health can be monitored and any problems that develop can be treated.