Dwarfism

Medically Reviewed By William C. Lloyd III, MD, FACS
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What is dwarfism?

Dwarfism refers to short stature caused by medical or genetic conditions. Most adults with dwarfism are no taller than 4 feet, 10 inches, with an average height of 4 feet. The condition is typically present from birth, though it may be recognized later (such as with a growth hormone deficiency that can arise in childhood due to illness or injury).

About 30,000 Americans are estimated to have dwarfism, which affects about 650,000 people worldwide. The most common condition causing dwarfism is achondroplasia, which is triggered by a genetic mutation that limits the ability of cartilage to become bone. Achondroplasia causes about 70% of dwarfism. Up to 400 other, more rare conditions also cause dwarfism.

Achondroplastic dwarfism results in people having disproportionate features: relatively large heads for their body size, plus shorter legs and arms than would be expected based on the size of their torsos. These differences are apparent from birth or early infancy. Often, people with achondroplasia or similar dwarfism-causing conditions experience medical complications, particularly painful orthopedic problems like spinal stenosis (caused by inadequate space for their spinal cord), or sleep apnea, which can impede breathing. Such complications may require surgery or other treatment, so regular contact with a physician is important.

People with dwarfism may encounter public misconceptions about their abilities. Most are not intellectually disabled and can hold jobs, raise families, and live normal lives, albeit with some accommodations needed to make up for their shorter stature (such as specially enabled cars and home adaptations). Advocacy groups promote “dwarf pride,” referring to dwarfism as a difference rather than a disability.

What are the different types of dwarfism?

Dwarfism can be divided into two general categories:

  • Disproportionate dwarfism, in which some parts of the body are small (such as arms and legs), while others are average size or above-average size. About 200 to 400 bone disorders can cause this type of dwarfism. The most common type is achondroplasia.
     
  • Proportionate dwarfism, when all body parts are small to the same degree and in the same proportions as in a person of average height. The most common cause of proportionate dwarfism is a hormone deficiency, such as lack of sufficient growth hormone during childhood.

One common misconception is that “midget” is a type of dwarf. This is not the case. The term “midget” started about 150 years ago, during a time when people of small stature were used as attractions in carnival “freak shows.” Today, “midget” is considered an offensive term by most people with dwarfism, who prefer to be referred to as “little people,” “people of small stature,” or “dwarf.”

What are the signs of dwarfism?

Signs and symptoms of dwarfism can vary, depending on the disorder causing the condition. Some signs can appear in utero, where the fetus might have an extra-large head or short arms compared to body size. These indicators of disproportionate dwarfism also may be apparent early in infancy. Other signs may not show up until later in childhood or even adulthood, especially in people with proportionate dwarfism.

Common signs of dwarfism

The most common symptoms of dwarfism include:

  • Adult height of 4 feet, 10 inches or less

  • Childhood height much lower than peers (2nd to 5th percentile on growth charts)

  • Disproportionately large head, prominent forehead, and flattened bridge of the nose

  • Mismatch in size between areas of the body, such as an average trunk size but shorter arms and legs (especially upper arms and legs) 

  • Short fingers, often with wide separation between middle and ring fingers

It can be important to identify dwarfism early so that doctors can promptly treat the disorder or its complications. For example, infants can be born with compression of the brain stem, which can lead to death if untreated. People with dwarfism will need to have regular medical care to manage their condition.

What does dwarfism look like?

People with dwarfism can live independently, have families, and lead productive lives. Some modification to their homes or workplaces may be necessary to accommodate shorter stature, disproportionate body areas. Dwarfism is commonly recognized in two categories: proportionate dwarfism and disproportionate dwarfism.

Dwarfish man walking with hands in pockets on city street
Getty

Proportionate dwarfism is when all body parts are small to the same degree and in the same proportions as in a person of average height.

Portrait of a dwarf woman using laptop working from home
Getty

Disproportionate dwarfism is when some parts of the body are small, while others are average size or above-average size.

What causes dwarfism?

Dwarfism can be caused by metabolic, hormonal and genetic conditions. The most common cause is achondroplasia, a genetic condition that prevents cartilage from being turned into bone, thus interfering with bone development and growth. Achondroplasia occurs in one in every 25,000 to 40,000 births.

In most cases (80%), children with achondroplasia are born to normal-size parents who do not have this condition. The genetic mutation that causes achondroplasia most often occurs during conception, from a random mutation in the sperm or egg, rather than inherited from a parent.

Many other conditions also cause dwarfism. Growth hormone disorders—often triggered by benign pituitary tumors—are the most common cause of proportional dwarfism. Pituitary gland injuries or birth defects (such as being born without a pituitary gland) can cause growth hormone deficiency, too, as can abnormalities in the hypothalamus. Malnutrition also has been linked to smaller than normal stature. For some people with dwarfism, the cause is not known.

What are the risk factors for dwarfism?

Dwarfism typically affects males and females equally, with one exception being dwarfism in females caused by a rare genetic condition that only females can get, called Turner syndrome. Dwarfism also is not linked to any particular race or ethnic groups. Most people are born with it or develop it soon afterward due to medical or genetic conditions.

Risk factors include:

  • Having at least one parent with a condition linked to dwarfism, such as achondroplasia

  • Having a growth hormone deficiency

  • Being severely malnourished in childhood

Genetic counseling for dwarfism risk

If you have dwarfism and are considering having a baby, genetic counseling may be helpful. For example, if you and your partner both have achondroplasia, your potential child would face the following odds:

  • 25% chance of not having achondroplasia (thus avoiding dwarfism)

  • 50% chance of having achondroplasia similar to what you have

  • 25% chance of having a “double mutation” of the achondroplasia gene mutation, which likely would cause your baby to die at birth or shortly thereafter

A genetic counselor can help you figure out your best reproductive options. Your primary care doctor can help you identify what has caused your dwarfism and can refer you for genetic tests and counseling, if needed.

What are the diet and nutrition tips for dwarfism?

People with dwarfism are at a high risk for obesity, which can take 10 to 20 years off a person’s life expectancy. More than half of those with achondroplasia are obese. One problem people with dwarfism face when trying to lose weight is that their smaller bodies require only about half as many calories as average-sized peers to maintain their weight—and even less (200 to 400 fewer calories) if they want to shed pounds.

In addition, some people with dwarfsim may not be as physically active as their peers and may not burn off calories through exercise in the same way. This is because people with dwarfism are prone to orthopedic conditions, such as spinal stenosis or joint problems, that make engaging in many exercises taxing or painful.

Experts have developed a food pyramid for little people, set for different calorie amounts (1,000, 1,400 and 1,800 per day), to help them lose or maintain weight. In general, these diets favor fresh fruits and vegetables, plus grains, dairy and protein.

Other diet and nutrition tips for those with dwarfism include:

  • Focusing on diet rather than exercise to lose weight

  • Eating a variety of foods to ensure necessary amounts of vitamins and minerals

  • Drinking lots of fluids

  • Having children learn to eat less during childhood than their average-sized siblings or friends, so they can make this a habit into adulthood

Ask your healthcare provider for guidance before making significant changes to your diet.

What are some conditions related to dwarfism?

People with dwarfism often suffer from related conditions. Some of the common ones include:

  • Spondyloepiphyseal dysplasias (SED), a type of bone disorder affecting one in 95,000 births. Some types of SED may not be noticed until a child reaches school age, while others are apparent at birth. They also are linked to clubfeet, cleft palate, and reduced joint mobility, as well as vision and hearing issues.

  • Diastrophic dysplasia, a disorder that, like achondroplasia, causes short limbs (particularly forearms and calves); it also may cause cleft palate, club feet, and joint changes limiting movement. Diastrophic dysplasia affects one in 110,000 births. 

  • Hypochondroplasia, a short-limbed type of dwarfism that often is not recognized until later childhood or even adulthood. About 10% of those with it have intellectual disability. It is caused by a different mutation of the same gene that causes achondroplasia.

  • Osteogenesis imperfecta (OI), also known as brittle bone disease, which causes frequent fractures as well as small stature

  • Growth disorders, in which too little growth hormone is released. (Conversely, some disorders cause too much growth hormone to be produced, causing gigantism in children and acromegaly—a form of gigantism—in adults.)

  • Hormone disorders. Some conditions cause lower levels of gonadotropins, which control male and female sex hormones, resulting in lack of pubertal development. Juvenile hypothyroidism can result in short stature due to less production of thyroid hormones needed for skeletal growth.

How do doctors diagnose dwarfism?

Disproportionate dwarfism is usually present or apparent in prenatal ultrasounds, at birth, or in early infancy, with trademark physical signs such as markedly short limbs compared to the trunk or an excessively large head. Proportional dwarfism may take longer to become apparent.

To diagnose your child’s condition, your doctor or licensed healthcare practitioner will:

  • Take careful measurements of your baby’s height, weight and head circumference, which may be repeated frequently if the doctor sees a pattern of abnormal growth

  • Order imaging tests, such as X-rays, MRIs and CT scans to check for abnormalities in your child’s skull, skeleton, pituitary gland or hypothalamus

  • Order genetic tests to determine which disorder is behind your or your child’s dwarfism, or as needed for family planning purposes

  • Take a detailed family history to look for signs of genetic dwarfism-related conditions

  • Order hormone tests to look at growth and other hormones.

What are the treatments for dwarfism?

Some dwarfism treatments aim to correct or treat dwarfism, while others focus on treating its side effects and complications.

Surgical treatments include:

  • Limb-lengthening, a controversial procedure in which surgeons supplement growth in legs and arms by inserting hardware in the bones. This adds height and arm length, both for functional and cosmetic purposes. The procedure carries a high risk of complications, including nerve injury, infection, fractures, osteoarthritis later in life, and unequal limb lengths, with success not guaranteed. Little People of America, an advocacy group for those with dwarfism, advises against limb-lengthening unless the person is of an age to give legal consent. 
  • Spinal procedures, such as surgery to correct spinal stenosis, which occurs when the opening in the spinal column is too small for the spinal cord, a common complication among people with dwarfism. Spinal instability may need to be corrected by inserting a metal rod to support the spinal column.
  • Joint replacement of hips and knees due to arthritis
  • Shunts inserted in the brain to drain excess cerebrospinal fluid, which is present in hydrocephalus, a common complication of dwarfism

Medical treatments include:

  • Injections of synthetic growth hormone for those with growth hormone deficiency; shots may be required daily for several years until maximum adult height is reached.
  • Supplementation of other hormones as needed. For example, females with Turner syndrome may need estrogen replacement therapy to enter puberty and reach adult sexual development. This may have to be continued throughout their lives, until they reach menopause.

A new medication may soon be available that targets the genetic mutation that causes achondroplasia. A recent study found that the medication vosoritide, in a phase 3 clinical trial, added about 0.6 inches of height in one year to people with dwarfism ages 5 to 17 who took it daily, compared to no additional growth among the control population. The makers of the medication have applied to the U.S. Food and Drug Administration for approval and are conducting trials in a younger age group (birth through age 4). This precision medication has drawn criticism by some dwarfism advocates for implying that dwarfism is a medical problem that needs correcting, as opposed to a difference that should be celebrated.

Home adaptations for dwarfism

People with dwarfism can usually live independently but may need some modifications of their homes and workplaces. For example, homes can be adapted with lower handrails in stairways, light-switch extensions, modifications of doorknobs so they can be more easily reached and turned, easy access to stools, appliances with special modifications that improve access, and furniture specially made for people of short stature. Cars can be fitted with hand controls if feet don’t reach pedals.

How does dwarfism affect quality of life?

Living with dwarfism can sometimes create social, emotional and psychological challenges. If you have dwarfism, you may encounter others who tease, bully or make unwarranted assumptions about your condition and abilities.

Other challenges include ongoing and often painful medical problems related to dwarfism, such as ear infections, sleep apnea, spinal stenosis, and other orthopedic complaints. Anything that causes pain and frustration can affect your quality of life.

You can improve your quality of life in several ways:

  • Connecting with other people with dwarfism through support groups, such as Little People of America. Such groups can often connect you with local services and other resources, as well as provide emotional support.

  • Improving your frame of mind through exercise, while making sure to choose non-impact activities, such as swimming or bicycling, which are easier on joints and limbs

  • Consulting with therapists as needed, including occupational therapists, who can provide recommendations and tools for living with dwarfism

If your child has dwarfism, encourage open discussion about teasing and other concerns, while also acting as your child’s advocate in school, especially if bullying is occurring. Role-play with your child to develop responses to teasing and bullying.

Your physician may also be able to help provide you with resources to help improve your quality of life.

What are the potential complications of dwarfism?

Dwarfism is associated with a variety of complications, which depend on which condition has caused short stature.

  • Orthopedic conditions, such as spinal stenosis (where the opening of the spinal canal is not large enough for the spinal cord), swayed or hunched back, bowed legs, and arthritis. These are common concerns, especially among people with achondroplasia or other disorders that cause disproportionate dwarfism.

  • Delays in a child’s motor skills development, such as taking longer to sit up, crawl and walk than those without dwarfism

  • Obstructive sleep apnea, due to smaller or improperly shaped airways, which can lead to failure to thrive in children, since breathing is stopped numerous times during the night 

  • More frequent ear infections, along with a risk of hearing loss

  • Hydrocephaly, which is an enlarged head caused by excess spinal fluid on the brain due to drainage openings in the skull being too small. (This can be corrected by inserting a shunt.)

  • Compression of the brain stem, caused by the base of the skull being too small for the spinal cord, which can result in central apnea and failure to thrive.

Does dwarfism shorten life expectancy?

Most people with dwarfism have a normal life expectancy. People with achondroplasia at one time were thought to have a life span shorter by about 10 years than the general population. However, changes in clinical management, especially in young children, has improved this picture so children under 4 with dwarfism have the same mortality rates as those without dwarfism. Dwarfism prognosis also depends on your underlying condition and its severity.

Keep in mind that studies don’t necessarily reflect your reality when it comes to living with dwarfism. By maintaining your health and having regular visits with your healthcare provider, you are more likely to improve both the quality and length of your life.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 30
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