Dwarfism and Skeletal Dysplasias

In skeletal dysplasias, like dwarfism, a child’s bones do not grow in the usual way. Often, children with skeletal dysplasias are much shorter than average, or their bones may be more fragile than is typical.

Dwarfism is a type of short stature that happens when a child’s bones cannot grow to a typical length. Instead, the bones are short and sometimes crooked. Your child’s arms, legs or trunk may be short compared with the rest of their body. The most common type of dwarfism is called achondroplasia (ay-con-druh-PLAY-zhuh).

• How common are skeletal dysplasias?

  There are more than 400 types of skeletal dysplasia. Together, these conditions affect 1 in 5,000 children. Achondroplasia affects 1 in 15,000 children.

• What causes skeletal dysplasias?

  Most of the time, skeletal dysplasia is caused by a problem with a gene involved in bone growth. Sometimes this gene is passed on from a parent to a child. Other times, a baby has a new random change in a gene, and they are the first in the family to have skeletal dysplasia. The gene change is not caused by something parents did or didn’t do before or during the pregnancy.

• What are other reasons a child may have short stature?

  Children can be shorter than others their age for many reasons. They may not have any form of skeletal dysplasia. They may have:

  • Parents with short stature
  • A problem with hormones that help control growth
  • A disease that affects the kidneys, heart or intestines
  • A problem with nutrition or digestion that stops calcium and vitamin D from working well in their bodies

Seattle Children’s Skeletal Health Program cares for babies, children, teens and some adults with dwarfism, other types of skeletal dysplasias and metabolic bone diseases. We see many children each year with these conditions.

• The experts you need are here
  • The Skeletal Health Program brings together orthopedic surgeons, endocrinologists, geneticists, genetic counselors, radiologists, nurses and nurse practitioners to provide comprehensive care for your child.
  • Medical centers that do not specialize in skeletal dysplasias rarely see these conditions. At Seattle Children’s, we see many children with skeletal dysplasia. Our team is highly skilled and very experienced in the treatments your child may need.
  • Our doctors and nurses are known worldwide for their expertise in dwarfism and skeletal dysplasias. We have written widely on the subject.
• Comprehensive care for your whole child
  • We begin by taking care to make the correct diagnosis and understand all the ways your child’s condition affects them. Careful diagnosis helps us make sure your child gets the right treatment — and that they avoid treatment they do not need.
  • Dwarfism and skeletal dysplasia can affect more than a child’s bones, muscles and joints. That’s why we connect you and your family with any expert your child may need across Seattle Children’s. For example, we often work with Neurosurgery, Sleep Medicine, Otolaryngology, Audiology, the Heart Center and Dentistry, as well as social services.
  • Experts in our Spine Program treat spine problems linked with dwarfism and skeletal dysplasias. We have the largest pediatric spine center in the Pacific Northwest. Our spine team cares for even the most complex spinal problems in children of all ages.
• We treat infants through adults
  • For some families, our work begins even before their baby is born. If a prenatal (before birth) ultrasound suggests that your developing baby may have a skeletal dysplasia, we work with Seattle Children’s Fetal Care and Treatment Center. Together, our experts provide diagnostic and counseling services to you and your family.
  • After birth, we tailor care to your child’s age and developmental stage. Our focus is always on your child’s long-term health and wellness. We help you learn what to expect during your child’s life, from birth to adulthood.
  • For young adult patients who are ready to move to adult care, we can guide you in finding local experts.
• Support for your whole family
  • We know it can be stressful to have a child with a skeletal condition and to find the treatment they need. Everyone at Seattle Children’s works to make your experience here as easy as we can on your whole family.
  • Your child’s team does more than plan and provide care for your child. We also make sure you and your child understand your child’s condition and treatment options.
  • Seattle Children’s supports your family with a range of resources. Our Child Life specialists, Family Resource Center and Guest Services are here to help.
  • For more support beyond our walls, the Skeletal Health Program has close relationships with:
    • Little People of America, Inc., the advocacy and support group for families with dwarfism
    • Osteogenesis Imperfecta Foundation
    • Camp Korey, which offers camps for children with skeletal dysplasia and metabolic bone diseases
• Research and advances to improve care
  • Our team has done research to expand medical knowledge about dwarfism and skeletal dysplasias and to improve care and quality of life for patients everywhere.
  • Seattle Children’s doctors helped to found the Skeletal Dysplasia Management Consortium. This international panel of experts developed evidence-based guidelines on how to diagnose and treat skeletal dysplasias. 
  • Our doctors were part of an international panel of experts that developed evidence-based guidelines to diagnose and treat foramen magnum stenosis in babies with achondroplasia. 
  • Our team did research on the medicine pamidronate (which slows bone breakdown) for children with severe osteogenesis imperfecta. It showed they were better able to take part in sports and other physical activities after using this medicine for a year.
  • We are involved in studies to check the results of 2 medicines that may help children with genetic conditions that affect bone health. They are vosoritide to increase height in children with achondroplasia and burosumab-twza to strengthen bones in children with X-linked hypophosphatemia (low levels of phosphorus in the blood).
  • Learn more about current orthopedics research at Seattle Children’s.

Children usually come to us after their parents, caregiver or doctors notice things like these:

• They are not growing as quickly as other children their age.
• Their arms and legs, trunk or face look different from other children’s.
• They get scoliosis before age 10.
• They break their bones more easily than usual, such as in osteogenesis imperfecta.

We will ask about your child’s growth and medical history and examine them. We may take X-rays and suggest other tests that can give us more details.  

• Growth and medical history

  When you come to our clinic, we ask about:

  • Your child’s growth history
  • The height of members of your child’s family
  • How the pregnancy went
  • Any health conditions your child has
  • If your child has met common developmental milestones
  • If anyone else in your child’s family has symptoms or features like theirs 
• Physical exam and X-rays

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

• Other tests your child may have
  • Blood and urine tests. We may take blood and urine samples from your child to test for levels of hormones and other chemicals. This may help us understand how your child is growing.
  • MRI or CT scan. Children may have other conditions that sometimes go along with skeletal dysplasias. So, we may ask your child to have an MRI (magnetic resonance imaging) scan or a CT (computed tomography) scan to check for signs of these conditions.
  • Sleep study. Often, children with dysplasias have trouble breathing at night (obstructive sleep apnea or central sleep apnea). We may ask your child to have a sleep study. This is a test to check how well your child sleeps and what happens in their body during sleep, like their brain waves, heartbeat and how well they breathe.
• Genetic counseling

  Our staff includes experts called genetic counselors who can help explain genetic conditions and the chance of having a child with a skeletal dysplasia.