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Spondyloepiphyseal Dysplasia Congenita (SEDc)

Medically reviewed by: Amy W. Anzilotti, MD

What Is Spondyloepiphyseal Dysplasia Congenita?

Spondyloepiphyseal dysplasia congenita (SEDc) is a type of skeletal dysplasia. Skeletal dysplasias are conditions that cause problems with how and bone grow.

Spondyloepiphyseal dysplasia congenita (spon-dih-lo-eh-pih-fih-SEEL dys-PLAY-zhuh kon-JEN-ih-teh) can lead to problems with hearing and seeing.

What Are the Signs & Symptoms of SEDc?

People with SEDc have dwarfism. They might also have:

  • a wide forehead and wide-set eyes
  • a round face with a flattened nose and small chin
  • cleft palate
  • tracheomalacia (weak, floppy windpipe), which can lead to breathing problems in babies
  • joint pain and stiffness
  • hip problems
  • flat feet
  • knock-knees (knees curve in)
  • curved spine
  • instability of the neck bones
  • vision problems
  • retinal detachment (peeling of the lining of the eye)
  • cataracts (clouding of the lenses in the eyes)
  • frequent ear infections
  • hearing loss

Most children with SEDc don’t have every sign and symptom listed here. There is a lot of variability.

What Causes SEDc?

SEDc happens because of a gene change (mutation). The changed gene causes a problem with the growth plate of the bone, which leads to abnormal bone growth and shape. The changed gene also works in the eyeball, which can lead to vision problems.

Another skeletal dysplasia — Kniest dysplasia — happens when there is a different change in the same gene. Because this change is in the same gene in both conditions, children with SEDc and Kniest dysplasia can have similar signs and symptoms.

SEDc can happen when a child inherits a changed gene from a parent or, more often, from a new changed gene (a new mutation and neither parent has SEDc).

A genetic counselor can help families understand how the condition can run in families.

How Is SEDc Diagnosed?

Sometimes SEDc is found before birth if a prenatal ultrasound shows short arms and legs. Genetic testing (through amniocentesis) can confirm the diagnosis. If there’s a family history of SEDc, and the family’s gene change is known, an amniocentesis or chorionic villus sampling (CVS) can check the fetus for it too.

SEDc may also be diagnosed at birth. The diagnosis is made based by looking at the child’s growth, physical features, X-rays, and testing for the gene change.

How Is SEDc Treated?

A team of health care specialists care for people with SEDc. The specialists can include:

How Can Parents Help?

Your child needs the support of family and friends. To help your child:

  • Treat your child according to their age, not their size, and encourage others to do the same.
  • Talk about or SEDc as a difference rather than a problem. Your attitude can help your child develop good self-esteem.
  • Find ways to adapt. For example, get a light switch extender and a stepstool so your child can turn the lights on and off. Encourage your child’s school to make similar changes that can help.
  • If someone asks a question about your child’s SEDc, answer as simply as possible. For example, if someone asks why your child is short, say, “Mateo is shorter because his bones grow differently than yours.” Then, mention something special about your child. For example, “Mateo has so many different interests. You should see his baseball card collection.” This shows your child that things other than SEDc make them special.
  • Teach your child that being teased or bullied is not OK. If your child is teased or bullied at school, work with your child, teachers, and administrators to end it.
  • Encourage your child to find a hobby or activity to enjoy. Help your child try many different activities, like sports, music, art, computers, writing, and photography. Be sure to check with your doctor about any sports your child should avoid.

What Else Should I Know?

To help your child stay well and manage any problems, it’s important for your child to have regular medical care. Be sure to go to all doctor visits, and follow all recommendations.

Health problems can come up that need to be treated right away. So regular medical follow-up should include exams by an:

  • ophthalmologist to check for nearsightedness and to check the retina
  • orthopedic doctor to watch for neck instability and other issues that can come up with the back and legs

Support groups also can be helpful for kids and their families. Ask the care team for recommendations. You also can find support and more information online at:

Medically reviewed by: Amy W. Anzilotti, MD
Date reviewed: October 2022