The Most Common Types of Dwarfism

Dwarfism occurs when a person has a short stature. It usually results in an adult height of four feet, 10 inches or shorter. For children, this means being below the height growth curve for their age. This would be less than the third percentile, meaning that 97% of children are taller at the same age.

The terms usually preferred by people with this condition are "short-statured" or "little person" rather than "​dwarf." The term "midget" is considered to be offensive by many people.

This article will discuss the various kinds of dwarfism. It will also talk about what causes dwarfism and how a doctor diagnoses it.

Types

More than 300 different conditions can cause dwarfism. All people with dwarfism have a short stature. But different things can cause dwarfism. And people with various types of dwarfism have different physical characteristics.

Most of the conditions are genetic or inherited at birth. They are also noticeable once the baby is born. There are two main categories of dwarfism:

• Disproportionate dwarfism: This means that a person has some average-size parts of the body, such as the head and/or trunk. But they also have some shorter-than-normal parts of the body, such as the legs and arms. The most common type of disproportionate dwarfism—and the most common type of dwarfism in general—is achondroplasia. This is when a person has a normal-size torso but short arms and legs.
• Proportionate dwarfism: This means that the person is smaller than average all over. Growth hormone deficiency dwarfism, primordial dwarfism, and Seckel syndrome are all types of proportionate dwarfism.

Dwarfism is a relatively rare condition. Each of the individual types of dwarfism is even rarer.

Achondroplasia

Achondroplasia makes up 70% of all cases of dwarfism. It affects about one of every 25,000 to 30,000 newborns.

With achondroplasia, there is a problem with the gene that allows the body to change cartilage to bone while growing. This often affects the long bones.

People with this type of dwarfism have:

• A relatively long trunk
• Short arms and legs
• Short hands and fingers, with the ring and middle fingers spreading away from each other
• A disproportionately large head with a prominent forehead
• Bowed legs
• A curved spine

Many people who have achondroplasia have hydrocephalus, which is fluid in the brain. Typically, hydrocephalus associated with achondroplasia is mild. But if it is severe or persistent, the doctor can place a shunt, which is like a drain from the brain into the abdomen.

Some people with achondroplasia also have apnea or sleep apnea. This is a medical condition where you stop breathing or your breathing slows down while you're sleeping.

Other Types

Examples of other types of dwarfism include:

• Diastrophic dwarfism, which includes some bone abnormalities, such as a cleft palate
• Spondyloepiphyseal dysplasias (SEC), which can include a cleft palate, barrel chest, and club feet
• Primordial dwarfism, which includes several genetic disorders, such as Russell-Silver syndrome and Seckel syndrome
• Hypopituitarism
• Jeune syndrome
• Hurler syndrome
• Schwartz-Jampel syndrome
• Pseudoachondroplasia, which is genetically different from achondroplasia and characterized by an average-sized head and bone problems

Causes

Dwarfism can be caused by a genetic condition. It can also be caused by a medical or hormonal condition.

Genetics

The majority of people with dwarfism have gene mutations. This means they have changes in specific genes. These mutations interfere with normal development. They may also affect the growth of the cartilage and bones in the body.

Since arms and legs have the longest bones, any problems with normal bone development usually result in shorter limbs. This leads to short stature.

Any genetic change that causes dwarfism can be inherited from parents. It may also develop during fetal development.

Two short-statured people can have a non-dwarf child. Average-sized parents can give birth to a child with achondroplasia.

Medical Causes

Some non-genetic types of dwarfism can be caused by a growth hormone deficiency. They can also occur if a baby or child's body does not get the nutrients that they need for growth and proper development. A specialist can usually treat these kinds of dwarfism using growth hormones.

Diagnosis

Doctors can diagnose some types of dwarfism during early pregnancy with genetic testing.

Ultrasounds can show shorter-than-average arms and legs, as well as whether the growing baby's head is larger than average. Often, however, dwarfism can't be diagnosed until after the baby is born.

Treatment

Dwarfism itself is not a disease, so there is no "cure." Most people with dwarfism have the same level of intelligence as a person with average height. They also lead healthy, active lives.

But the conditions that cause dwarfism can cause health complications. These health complications often involve the spine and lower limbs.

Some medical issues relating to dwarfism are treated with surgery. These surgeries are usually performed on the following parts of the body:

• Back
• Neck
• Leg
• Foot
• Middle ear

Surgical treatments can help improve a little person's quality of life and survival.

If a child is very short, they might not receive a diagnosis of dwarfism when there are no other features besides short stature. Many people who are on the short side of the normal growth spectrum do not have dwarfism.

Summary

Dwarfism occurs when a person has short stature. Different things cause dwarfism. Most forms of dwarfism are genetic or inherited at birth. More than 300 genetic conditions can cause dwarfism. It can also be caused by a medical or hormonal condition.

Dwarfism is not a disease, so there is no "cure." Most people with dwarfism have the same level of intelligence as people of average height. They can also lead healthy, active lives just like any other person.