Dwarfism is a condition characterised by restricted growth, which results in unusually short stature. Typically, a person with dwarfism is shorter than 4 ft 10 and presents with a proportionate or disproportionate short stature.1 There are over 200 types of dwarfism caused by a range of medical conditions, however, only a few cause medical complications.2 80% of those with dwarfism have average-sized parents and siblings. In these cases, dwarfism is often caused by spontaneous genetic mutation.2
Types of dwarfism
There are two types of dwarfism: proportionate and disproportionate.3 Proportionate dwarfism is typically caused by a hormone deficiency, which can often be treated with hormone injections at a young age.2 On the other hand, disproportionate dwarfism is characterized by short arms and legs. Disproportionate short stature is commonly caused by achondroplasia, a genetic condition that affects bone growth.1 This type of dwarfism can also be caused by genetic syndromes such as Noonan syndrome, Turner syndrome, and Prader-Willi syndrome, as well as disrupted levels of growth hormone.1
Causes of dwarfism
Achondroplasia is a genetic condition which commonly causes dwarfism.3 It is the most common cause of dwarfism with 1 in 15-25,000 being affected.4 Interestingly, 4 out of 5 people with this condition have parents who are of average height.2,3 Achondroplasia is caused by an autosomal dominant genetic mutation in the fibroblast growth factor receptor 3 (fgfr3) gene which is responsible for regulating bone growth.4
Another genetic condition that can cause dwarfism is Turner syndrome, which only affects males and is caused by inheriting a non-functioning X chromosome.3 Dwarfism can also be caused by a growth hormone deficiency. For instance, hypothyroidism is caused by an underactive thyroid, and in addition to stunted growth, it can lead to cognitive difficulties and low energy.3 Intrauterine growth retardation, which occurs in the mother's womb, is another condition that can cause dwarfism.3
Signs and symptoms of dwarfism
The most common sign of dwarfism is short stature. People with disproportionate short stature (DSS) will have other recognizable traits, such as short arms and legs, a large head with a prominent forehead and flat nasal bridge, short and wide hands and feet, with short fingers and toes.1
Management and treatment for dwarfism
Achondroplasia, the most common cause of dwarfism, can require lifelong symptom management and surgical procedures.4 Hormone therapy can be used in the management of certain conditions. For example, in Turner syndrome, estrogen therapy and hormones can be used to trigger puberty.3 Surgical options are also available to correct bone growth direction, stabilise the spine, and increase the channel vertebrate surrounding the spinal cord to relieve pressure.3 Additionally, physical therapy and orthotics can be used to manage the condition.1
Surgical treatments are options fo rboth proportionate and disproportionate dwarfism.4 Surgically lengthening the limbs is an option where over many months external fixators are tightened to lengthen the limb.4 This procedure, known as the Ilizarov procedure, can help to improve life quality and allow functional gains.4 Risks of the procedure can include fractures, infection and muscle contractures.4 Intramedullary fixation is another limb-lengthening procedure that is controversial which requires bone breaking and fixation.4
Diagnosis of dwarfism
Dwarfism can often be diagnosed based on a newborn's appearance, but further tests can be performed to confirm the diagnosis.4 Additionally, genetic testing, ultrasounds, and X-rays can be used to diagnose dwarfism.2 If growth hormone (HGH) deficiency is suspected, HGH stimulation tests can be used to confirm the diagnosis.1 If blood and stimulation tests reveal low growth hormone levels, brain scans can be done to inspect the pituitary gland.1,3
There are several risk factors associated with dwarfism. Hormone deficiency and malnutrition are risk factors for dwarfism.3 Other risk factors include a family history of dwarfism, maternal health during pregnancy and inherited genetic conditions.
In general, dwarfism does not cause serious health problems, and people with this condition are expected to have a normal life expectancy.1 However, some medical issues may arise, such as hydrocephalus, which is a build up of fluid in the brain, spinal stenosis (spinal pressure), and arthritis.2 In addition, people with dwarfism may experience bowed legs, back hunching, and sleep apnea.3 Babies may also experience delayed motor skill development and weight gain that can put pressure on joints. Pregnancy in those with dwarfism can also present respiratory issues and often require a cesarean section.3
Can dwarfism be prevented
Although there is no way to entirely prevent dwarfism, those with the condition can lead relatively normal lives. Dwarfism is either inherited or spontaneous genetic mutations.
How common is dwarfism
In the UK, approximately 1 in 25,000 people are born with dwarfism, which means there are 3,000-7,000 people living with this condition across the country.2
When should I see a doctor
You should see a doctor if your child has obvious delayed growth for a physical exam.
Restricted growth resulting in dwarfism can be caused by various medical conditions that may lead to either proportional or disproportional dwarfism. Physical examination of newborns can assist in the diagnosis of dwarfism, but additional tests and pre-birth screenings may also be necessary. Although many individuals with dwarfism do not experience health complications, certain medical conditions such as arthritis, hydrocephalus, and spinal stenosis may arise. Risk factors for dwarfism include malnutrition, family history, and hormone deficiency.
- Restricted growth (Dwarfism) [Internet]. nhs.uk. 2017 [cited 2023 Apr 27]. Available from: https://www.nhs.uk/conditions/restricted-growth/
- Dwarfism facts [Internet]. [cited 2023 Apr 27]. Available from: https://littlepeopleuk.org/information-about-dwarfism-conditions/dwarfism-facts
- Dwarfism: types, causes, and more [Internet]. Healthline. 2017 [cited 2023 Apr 27]. Available from: https://www.healthline.com/health/dwarfism
- Ornitz DM, Legeai-Mallet L. Achondroplasia: development, pathogenesis, and therapy. Dev Dyn [Internet]. 2017 Apr [cited 2023 May 7];246(4):291–309. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5354942/