Dwarfism is short stature that results from a genetic or medical condition. Dwarfism is generally defined as an adult height of 4 feet 10 inches (147 centimeters) or less. The average adult height among people with dwarfism is 4 feet (122 cm).
Many different medical conditions cause dwarfism. In general, the disorders are divided into two broad categories:
Some people prefer the term "short stature" or "little people" rather than "dwarf" or "dwarfism." So it's important to be sensitive to the preference of someone who has this disorder. Short stature disorders do not include familial short stature — short height that's considered a normal variation with normal bone development.
Signs and symptoms — other than short stature — vary considerably across the spectrum of disorders.
Most people with dwarfism have disorders that cause disproportionately short stature. Usually, this means that a person has an average-size trunk and very short limbs, but some people may have a very short trunk and shortened (but disproportionately large) limbs. In these disorders, the head is disproportionately large compared with the body.
Almost all people with disproportionate dwarfism have normal intellectual capacities. Rare exceptions are usually the result of a secondary factor, such as excess fluid around the brain (hydrocephalus).
The most common cause of dwarfism is a disorder called achondroplasia, which causes disproportionately short stature. This disorder usually results in the following:
Another cause of disproportionate dwarfism is a rare disorder called spondyloepiphyseal dysplasia congenita (SEDC). Signs may include:
Proportionate dwarfism results from medical conditions present at birth or appearing in early childhood that limit overall growth and development. So the head, trunk and limbs are all small, but they're proportionate to each other. Because these disorders affect overall growth, many of them result in poor development of one or more body systems.
Growth hormone deficiency is a relatively common cause of proportionate dwarfism. It occurs when the pituitary gland fails to produce an adequate supply of growth hormone, which is essential for normal childhood growth. Signs include:
Signs and symptoms of disproportionate dwarfism are often present at birth or in early infancy. Proportionate dwarfism may not be immediately apparent. See your child's doctor if you have any concerns about your child's growth or overall development.
Most dwarfism-related conditions are genetic disorders, but the causes of some disorders are unknown. Most occurrences of dwarfism result from a random genetic mutation in either the father's sperm or the mother's egg rather than from either parent's complete genetic makeup.
About 80 percent of people with achondroplasia are born to parents of average height. A person with achondroplasia and with two average-size parents received one mutated copy of the gene associated with the disorder and one normal copy of the gene. A person with the disorder may pass along either a mutated or normal copy to his or her own children.
Turner syndrome, a condition that affects only girls and women, results when a sex chromosome (the X chromosome) is missing or partially missing. A female inherits an X chromosome from each parent. A girl with Turner syndrome has only one fully functioning copy of the female sex chromosome rather than two.
The cause of growth hormone deficiency can sometimes be traced to a genetic mutation or injury, but for most people with the disorder, no cause can be identified.
Other causes of dwarfism include other genetic disorders, deficiencies in other hormones or poor nutrition. Sometimes the cause is unknown.
Complications of dwarfism-related disorders can vary greatly, but some complications are common to a number of conditions.
The characteristic features of the skull, spine and limbs shared by most forms of disproportionate dwarfism result in some common problems:
With proportionate dwarfism, problems in growth and development often result in complications with poorly developed organs. For example, heart problems that often occur with Turner syndrome can have a significant effect on health. An absence of sexual maturation associated with growth hormone deficiency or Turner syndrome affects both physical development and social functioning.
Women with disproportionate dwarfism may develop respiratory problems during pregnancy. A C-section (cesarean delivery) is almost always necessary because the size and shape of the pelvis doesn't allow for successful vaginal delivery.
Most people with dwarfism prefer not to be labeled by a condition. However, some people may refer to themselves as dwarfs, little people or people of short stature. The word "midget" is generally considered an offensive term.
People of average height may have misconceptions about people with dwarfism. And the portrayal of people with dwarfism in modern movies often includes stereotypes. Misconceptions can impact a person's self-esteem and limit opportunities for success in school or employment.
Children with dwarfism are particularly vulnerable to teasing and ridicule from classmates. Because dwarfism is relatively uncommon, children may feel isolated from their peers.
Your pediatrician will likely examine a number of factors to assess your child's growth and determine whether he or she has a dwarfism-related disorder. In some cases, disproportionate dwarfism may be suspected during a prenatal ultrasound if very short limbs disproportionate to the trunk are noted.
Diagnostic tests may include:
A number of disorders causing dwarfism can cause a variety of developmental problems and medical complications. Several specialists may be involved in screening for specific conditions, making diagnoses, recommending treatments and providing care. This team may evolve as your child's needs change, and your family doctor or pediatrician can coordinate the care.
Specialists in your care team may include:
The goal of treatment is to maximize functioning and independence. Most dwarfism treatments don't increase stature but may correct or relieve problems caused by complications.
Surgical procedures that may correct problems in people with disproportionate dwarfism include:
For individuals with dwarfism due to growth hormone deficiency, treatment with injections of a synthetic version of the hormone may increase final height. In most cases, children receive daily injections for several years until they reach a maximum adult height — often within the average adult range for their family.
Treatment may continue throughout the teen years and early adulthood to ensure adult maturation, such as appropriate gain in muscle or fat. Some individuals may need lifelong therapy. The treatment may be supplemented with other related hormones if they are also deficient.
Treatment for girls with Turner syndrome also requires estrogen and related hormone therapy in order for them to begin puberty and achieve adult sexual development. Estrogen replacement therapy usually continues throughout life until women with Turner syndrome reach the average age of menopause.
Growth hormone supplementation for children with achondroplasia does not increase final adult height.
Regular checkups and ongoing care by a doctor familiar with dwarfism can improve quality of life. Because of the range of symptoms and complications, treatments are tailored to address problems as they occur, such as assessment and treatment for ear infections, spinal stenosis or sleep apnea.
Adults with dwarfism should continue to be monitored and treated for problems that occur throughout life.
Some people with dwarfism choose to undergo surgery called extended limb lengthening. This procedure is controversial for many people with dwarfism because, as with all surgeries, there are risks. Waiting to decide about limb lengthening until the person with dwarfism is old enough to participate in the decision is recommended because of the emotional and physical stress involved with multiple procedures.
Talk with your pediatrician or a specialist about at-home care. Issues particularly critical for children with disproportionate dwarfism include:
If your child has dwarfism, you can take a number of steps to help him or her cope with challenges and function independently:
How you learn whether your child has dwarfism will depend on the degree to which it affects his or her development. Disproportionate dwarfism is usually apparent at birth or early in infancy. Proportionate dwarfism may not be diagnosed until later in childhood or the teenage years if your child isn't growing at an expected rate.
It's important to take your child to all regularly scheduled well-baby visits and annual appointments throughout childhood. These visits are an opportunity for your child's doctor to track growth, note delays in expected growth and identify other problems in physical development.
Questions your child's doctor may ask include:
If your family doctor or pediatrician believes that your child exhibits signs of dwarfism, you may want to discuss these questions:
Preparing and anticipating questions will help you make the most of your appointment time.