A Specialized Approach to Skeletal Dysplasia & Dwarfism

Understanding Skeletal Dysplasia and Dwarfism

Skeletal dysplasias, also known as Dwarfism, are a group of more than 300 genetic disorders that affect bone development, neurological function and cartilage growth, usually causing short stature. A person is considered to have dwarfism when their adult height is 4 feet 10 inches or less. The condition affects 1 in 5,000 children.

What Are the Different Types of Skeletal Dysplasia and Dwarfism?

In general, the disorders are divided into two categories:

Proportionate Dwarfism

Proportionate dwarfism is when a person’s body parts are in proportion but shortened. This is often due to metabolic and hormonal disorders such as a deficiency in the human growth hormone.

A person may have a head, limbs, and trunk that are short but still proportionate to one another. This type of dwarfism can affect other parts of the body, like the heart. Proportionate dwarfism is often caused by another medical condition that limits growth and development. One of the most common causes is growth hormone deficiency—a condition where a child’s pituitary gland doesn’t produce enough growth hormone to help the body grow.

Disproportionate Dwarfism

Disproportionate dwarfism is when a person has body parts that are not proportionate to each other—they can be several different sizes. In most cases, the trunk is average-sized and the limbs are short. However, it’s also possible that a person could have a very short trunk, and limbs that are technically “short” but appear large compared to the trunk.

The most common types and symptoms of disproportionate dwarfism:

Achondroplasia

Achondroplasia is the most common type of dwarfism, causing about 70% of cases. It occurs when cartilage – the tissue that makes up most of a fetus’s skeleton during development – doesn’t convert to bone the way normal cartilage does resulting in a usually normal torso and shortened limbs.

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Spondyloepiphyseal Dysplasia Congenita (SEDc)

SEDc is a rare genetic disorder that results in short stature and skeletal abnormalities that primarily affect the spine and long bones of the arms and legs.

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Diastrophic Dysplasia

Diastrophic dysplasia is a disorder that affects the body’s ability to form cartilage and bone development and results in short stature, joint and hand deformities, and abnormal curving of the spine.

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Pseudoachondroplasia

Pseudoachondroplasia is a rare form of dwarfism that affects bone grown. Children with pseudoachondroplasia have a normal head size, facial features and intelligence level. However, they are small in stature.

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Hypochondroplasia

Hypochondroplasia is a form of short-limbed dwarfism. Like other forms of dwarfism, it occurs when a fetus is still in the womb and there is a problem related to the cartilage converting into bone. It is considered a milder form of dwarfism.

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Turner Syndrome

Turner syndrome is a type of dwarfism that only affects females. In addition to being short in stature, girls with Turner syndrome often have heart defects and their ovaries do not develop normally. Often girls with Turner syndrome grow normally, then around age 5 their growth slows and their short stature becomes noticeable.

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The common symptoms of skeletal dysplasia

Skeletal dysplasia has many signs and symptoms, including:

• A small thorax
• Abnormal ribs
• Bowed or fractured bones
• Shortening in the bones of the legs and/or arms
• Asymmetric bone growth
• Duplication of fingers or toes
• Irregular, thickened or thin bones

Diagnosing Skeletal Dysplasia & Dwarfism

Physical appearance is often enough to alert a doctor to your child’s dwarfism. If our doctors suspect dwarfism, they may run a number of tests:

• Imaging tests: Tests like X-rays and magnetic resonance imaging (MRI) can help the physician see abnormalities of the head and body in more detail. They can also show problems with the hypothalamus or pituitary gland—body parts associated with growth hormone.
• Hormone tests: These tests check levels of hormones that are needed for proper development, like growth hormone.
• Family history: Since dwarfism often runs in families, getting a family history can help the physician determine whether the child’s short stature is the average size for the family.

The Right Treatment for Kids with Skeletal Dysplasia & Dwarfism

Treatment for disproportionate dwarfism usually doesn’t make a child taller. However, there are treatments for complications caused by dwarfism. These may include:

• Surgery: A surgeon may be able to take steps such as correcting a spine that isn’t forming in the normal shape, or bones that aren’t growing in the right direction.
• Growth hormone therapy: A child with dwarfism caused by abnormal hormone levels may receive injections of growth hormone. This can only correct short stature in a child with proportionate dwarfism.
• Estrogen therapy: This treatment may be given to a female child with Turner syndrome. Estrogen will initiate puberty, and can stimulate growth of her sex organs. This therapy can also help her pay attention, plan tasks and have a better sense of visual or spatial relationships.