Chromosomal and Genetic Conditions

Dwarfism and Bone Dysplasias

What Is Dwarfism and Bone Dysplasia?

Note the short proximal limb segments with preservation of trunk length. Courtesy of 'Practice of Pediatric Orthopedics,' ©2001 Lippincott Williams and Wilkins

Achondroplasia. Note the short proximal limb segments with preservation of trunk length.

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.

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 the body.

Children can be shorter than others their age for many reasons. They may have:

  • Short parents
  • A lack of the hormones that help control growth
  • An ongoing disease affecting the kidneys, heart or intestines
  • A nutritional or digestive problem that stops calcium and vitamin D from working properly in their bodies and promoting growth

Dwarfism and Bone Dysplasias in Children

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 the family to be affected.

Dwarfism and Bone Dysplasias at Seattle Children's

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. Our staff has long experience in treating them.

Both the orthopedic doctors and geneticists on our staff have cared for children with dysplasias. 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, find out 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, endocrinology, otolaryngology and social services, also may help to care for your child. Spine problems linked with dwarfism and bone dysplasias are treated by the experts in our Spine Program.

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

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