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Dwarfism and Bone Dysplasias

What are dwarfism and bone dysplasias?

Bone dysplasias are a group of more than 150 disorders in which a child’s bones do not grow the way bones usually do. Often, children who have bone dysplasias are very short.

Children can be shorter than others their age for many reasons. They may have short parents or lack the hormones that help control growth. They may have an ongoing disease affecting the kidneys, heart or intestines, or a nutritional or digestive problem that stops calcium and vitamin D from working properly in their bodies and promoting growth.

Dwarfism is a particular type of short stature that happens when the bones do not have the ability to grow to an average length. Instead, they are short and sometimes crooked. The child’s arms, legs or trunk may be short in comparison with the rest of her body.

Children with dwarfism are very far below average height for their age. They may not have full motion in their joints and they sometimes have bowlegs or knock-knees.

How do you evaluate dwarfism and bone dysplasias?

Achondroplasia
Achondroplasia

Children usually come to us after their parents or doctors notice that they are not growing as quickly as other children their age, or that their arms and legs, trunk or face look different from other children’s.

When you come to our clinic, we will ask about your child’s growth history. We also will ask about the height of members of your child’s family, and how the mother’s pregnancy progressed.

We will want to know about any medical conditions your child has, and any similar problems in the rest of your family.

Next, we will examine your child. We will measure her height and the length of her arms and legs. We will take X-rays of her arms, legs, pelvis, spine and skull. This is called a skeletal survey, and it helps us find out which bones may not be growing the way they usually do in children.

We may also take blood samples from your child so that we can test for levels of hormones and other chemicals that can help us understand how your child is growing.

Because children may have other conditions that come along with bone dysplasias, we may ask your child to have an MRI or a CT scan to check for other problems.

Often children with dysplasias have difficulty breathing at night (sleep apnea), and so we may ask them to have a sleep study.

Sometimes, pregnant women have ultrasound tests that raise concerns about the growth of the fetus in their womb. In these cases, we take specific ultrasound images that can help identify bone dysplasias before birth.

Who gets dwarfism and bone dysplasias?

Bone dysplasias and dwarfism are rare. The most common type of dwarfism (achondroplasia) occurs in one in 15,000 children.

A defective gene that stops bone from growing in the usual way causes most bone dysplasias. Sometimes this gene is passed on from a parent to a child (genetic).

Much more often, though, the condition arises from a new change in the gene (spontaneous genetic mutation), and the baby is the first in her family to be affected.

What is your experience with dwarfism and bone dysplasias?

At Children’s Hospital, we have cared for children with genetic conditions since the 1960s.

The team at our Skeletal Health and Genetics Clinic specializes in diagnosing and caring for children with rare bone conditions, and our staff has long experience in treating them.

Both the orthopedic doctors and geneticists on our staff have cared for children with dysplasias, and they have done research that expands medical knowledge about dysplasia.

We have also written widely on the subject, and have been active with Little People of America, Inc., the advocacy and support group for families with dwarfism.

Our goal is to accurately identify your child’s condition, determine if there are any further problems associated with it and help you learn what to expect throughout your child’s life — from childhood through adolescence to adulthood.

Our team includes geneticists, orthopedic doctors, genetic counselors, radiologists, nurses and advanced nurse practitioners. Our consultants in other specialties, including neurosurgery, otolaryngology and social services, also may help to care for your child.

Our clinic also provides medical care and therapy to adults with dwarfism and rare bone conditions. When adult patients need surgery, we work with the University of Washington.

When a pregnant woman’s ultrasound image suggests that her fetus may have a bone dysplasia, we provide diagnostic and counseling services to her and her family.

How do you treat dwarfism and bone dysplasias?

Our goal is to help children, teenagers and adults with bone dysplasias function well and have a high quality of life. This means we are ready to treat all aspects of the disorder, from medical problems to social and family issues.

We understand the social and physiological challenges faced by children with rare conditions and their families. We offer supportive social, medical and psychological services, both at Children’s Hospital and in the child’s community. We encourage contact with organizations such as LPA.

Orthopedic treatment

The major deformities of children with skeletal dysplasias affect the arms, legs and spine. In some cases, surgery can help correct these deformities.

These conditions are rarely seen at medical centers that do not specialize in bone dysplasias. Our orthopedic staff is highly skilled and very experienced in treating these conditions. When orthopedic treatment may be helpful, we manage all aspects of care.

Surgery to correct limb problems

Sometimes arms and legs grow crooked, causing hip or knee pain and making walking and running difficult. In some cases, operations to realign these joints may be helpful.

These operations include:

  • Inserting metals staples into the growth plate in one or more of your child’s bones to correct the way a limb is growing
  • Dividing a bone, straightening it and then fixing it in place using metal plates and screws

When arms and legs are so short that it is difficult for your child to manage daily activities such as personal hygiene, you and your doctor may consider limb lengthening. In this operation, the doctor cuts a bone into two pieces.

Then, over a period of time, the two pieces of bone are gradually pulled apart (distracted) while new bone forms in between them, thus making the healed bone longer.

Surgery to correct spine problems

Curving in the backbone (scoliosis) is a common problem for children with dwarfism. If your child has severe scoliosis, you and your doctor may consider surgery that uses metal rods and screws to help straighten the spine.

Spinal stenosis, a condition in which the canal that the spinal cord runs through is narrower than usual, is another condition that often affects people with dwarfism. It can put pressure on the spinal cord, causing pain and weakness in your child’s arms and legs. It may also interfere with normal breathing.

In these cases, you and your child’s doctor may consider an operation to open up the spinal canal to take pressure off the spinal cord and nerves.

Diagnostic and genetic counseling services

We provide diagnostic services for both children and pregnant women, and genetic counseling for families. Our staff includes experts who can help explain genetic conditions and the possibilities of having a child with a bone dysplasia.

Learn more about genetic testing for achondroplasia.