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Dwarfism

What Is Dwarfism?

Here are some facts that people may not realize about dwarfism.

Dwarfism:

  • is characterized by short stature. According to Little People of America (LPA), an advocacy group for people with dwarfism and their families, this means a final height of 4 feet 10 inches or less.
  • can and most often does happen in families where both parents are of average height
  • is often caused by one of over 400 skeletal dysplasias (diss-PLAY-zhee-uhs). These affect bone and growth, and often lead to disproportional short stature.

The most common type of dwarfism is achondroplasia (pronounced: ay-kon-dreh-PLAY-zyuh).

Dwarfism is not:

  • an intellectual disability. Most people with dwarfism have typical intelligence.
  • a disease that requires a "cure." Most individuals with dwarfism live long, fulfilling lives.
  • a reason to assume someone is incapable. Individuals with dwarfism go to school, work, drive cars, marry and raise children, just like their average-height peers.

What Causes Dwarfism?

Most types of dwarfism are caused by a genetic change (mutation) in an egg or sperm cell that happens before the start of pregnancy (conception). Others happen because of a genetic change(s) inherited from one or both parents. Genetic changes happen randomly. There is nothing a parent could do before or during pregnancy to prevent this change from happening. A genetic counselor can help determine the chances of having a child with dwarfism.

Depending on the type of dwarfism, two average-height parents can have a child with short stature. It's also possible for two parents with dwarfism to have an average-height child.

What Are the Types of Dwarfism?

Individuals with dwarfism all have short stature. But there are many different causes of dwarfism. Each has their own unique features and physical traits.

In general, dwarfism caused by a skeletal dysplasia results in disproportionate short stature. This means that the limbs (arms and legs) and the trunk are not of the same proportion as average-height individuals.

The two types of this disproportion are short-trunk and short-limb:

  • Short-trunk dwarfism: The torso is shortened when compared with the limbs.
  • Short-limb dwarfism: The limbs are shortened when compared with the trunk.

By far the most common skeletal dysplasia is achondroplasia. This short-limb dwarfism happens in about 1 of every 25,000 babies born of all races and ethnic groups. People with achondroplasia have a relatively long trunk and shortened arms and legs. This is most noticeable in the upper parts of their arms and legs (called rhizomelic shortening).

Other common features may include:

  • a larger head with a prominent forehead
  • a flattened bridge of the nose
  • shortened hands and fingers
  • a sway of the lower back
  • bowed legs

The average adult height for someone with achondroplasia is around 4 feet tall.

Diastrophic dysplasia is another short-limb dwarfism. It happens in about 1 in 100,000 births. People who have this type tend to have shortened forearms and calves (called mesomelic shortening). They might also have:

  • a cleft palate
  • changes in the outer ear (also known as a cauliflower-like appearance)
  • differently positioned thumbs (also called hitchhiker thumbs)
  • clubfeet (inward or downward pointing feet)
  • spine curves that can change over time

Most people with diastrophic dysplasia have joint changes that limit movement. People with diastrophic dysplasia often benefit from mobility aids, such as crutches, a scooter, or a wheelchair to get around.

Spondyloepiphyseal dysplasias (SED) are short-trunk skeletal dysplasias that involve the spine and the end of the bones that make up the joints (epiphyses). Along with achondroplasia and diastrophic dysplasia, they're one of the more common types of dwarfism. In one type of SED, the short trunk may not be noticed until the child is school age. Other types are seen at birth.

Someone with an SED also might:

  • be born with clubfeet and/or cleft palate
  • have vision and/or hearing differences
  • have instability of the spine and/or curves in the spine that change over time
  • develop reduced joint mobility and arthritis early in life

How Is Dwarfism Diagnosed?

Most pregnant women have a prenatal ultrasound to measure the baby's growth at around 20 weeks. At that stage, features of achondroplasia aren't yet noticeable. Doctors sometimes suspect achondroplasia before birth if an ultrasound late in a pregnancy shows that a baby's arms and legs are shorter than average and the head is larger. But many children with achondroplasia aren't diagnosed until after birth.

Doctors can recognize some other types of skeletal dysplasia earlier in pregnancy. Others aren't noticed until the first few months or years of life, when a child's growth slows. A health care provider may take X-rays after birth to check for bone changes. Doctors also may use genetic testing before or after birth to confirm the diagnosis.

Possible Complications and Treatments

Each condition that causes dwarfism has its own possible medical complications, which can change over time. But doctors can treat many of these.

People with dwarfism are cared for by doctors who specialize in orthopedics, neurosurgery, ENT, and pulmonology. Some medical concerns are treated with surgery. These are done with anesthesia, which can be more of a risk for little people because of their smaller body size and airways.

People with dwarfism should try to keep a healthy weight. A few extra pounds can puts harmful stress on the back and joints. It's important for them to find safe and enjoyable physical activities.

What Else Should I Know?

People with dwarfism can lead healthy, active lives. The Americans with Disabilities Act protects their rights.

Types of skeletal dysplasia and the severity of medical needs vary from person to person. In general, with proper medical care, life span is not affected by dwarfism.

Most of the complications that happen in people with dwarfism are physical, not intellectual. In fact, little people often find clever ways to do things in the average-size world. They also interact with people unfamiliar with dwarfism who make assumptions about it. While that can be tough and awkward at times, it's also a chance to enlighten people who don't know much about dwarfism.

Date reviewed: September 2020