Spondyloepiphyseal dysplasia congenita (SEDc) is a rare genetic disorder that results in short stature and skeletal anomalies that primarily affect the spine and long bones of the arms and legs. A form of dwarfism, children with SEDc often have vision and hearing issues. The condition is present at birth.
People with SEDc are short; adult height ranges from 34 to 57 inches tall. Their feet, hands and head are regular size, but their legs, arms and spine are shortened.
Children with SEDc can have a number of musculoskeletal problems including an unstable neck, loose ligaments, poor muscle tone, back and spine issues, hip deformities, foot issues and degenerative joint disease in the hips, knees or shoulders.
Children with the disorder may also have craniofacial deformities including a cleft palate, a flat face and hypertelorism (wide-set eyes).
SEDc is rare, occurring in less than 1 in 100,000 births. It occurs equally in males and females.
SEDc is caused by a mutation in COL2A1 (type II collagen alpha 1 chain) on chromosome 12. The mutation affects the collagen and connective tissues in the bones, eyes and other parts of the body.
Most cases of SEDc result from new mutations of this gene and occur in families with no history of the disorder. However, SEDc can be inherited. The condition generally follows an autosomal dominant pattern, meaning if one parent has the disorder, each of their children has a 50 percent chance of inheriting it. Some cases of autosomal recessive inheritance have also been reported in children with SEDc.
Signs of SEDc can vary from child to child, but may include:
- Bone deformities, including short stature, short body trunk, long limbs in relation to their frame, hip deformities such as coxa vara, and an unstable neck
- Back and spine issues, such as scoliosis, lordosis, kyphosis
- Musculoskeletal pain, including osteoarthritis, hip and joint pain
- Muscle and joint issues, such as poor muscle tone and joint problems
- Foot deformities, including club feet, flat feet and feet that turn inward
- Mobility issues, such as a waddling gait, stiff joints, loose ligaments and decreased ability to walk
- Craniofacial deformities, such as cleft palate, flat face and wide-set eyes
- Hearing and vision problems, including decreased vision, hearing deficits and deafness
- Digestive and stomach issues, such as inguinal hernia and a belly that sticks out
- Respiratory issues related to abnormal chest development, such as breathing problems and sleep apnea
Diagnostic evaluation usually begins with a thorough medical history and physical examination of your child. At Children’s Hospital of Philadelphia (CHOP), clinical experts use a variety of diagnostic tests to diagnose SEDc and possible complications, including:
- X-rays, which produce images of bones.
- Magnetic resonance imaging (MRI), which uses a combination of large magnets, radiofrequencies and a computer to produce detailed images of organs and structures within the body.
- Genetic testing, in which a sample of your child’s saliva or blood is used to identify your child’s DNA.
- Hip arthrography, which uses X-rays and dye injected into the joint to show the soft tissues (ligaments, tendons, cartilage and muscles) of the joint.
- EOS imaging, an imaging technology that creates 3-dimensional models from two planar images. Unlike a CT scan, EOS images are taken while the child is in an upright or standing position, enabling improved diagnosis due to weight-bearing positioning.
- Vision and hearing tests, which assess eye and ear function levels.
- Pulmonary function tests, which test how well the lungs are working.
All of these tests allow clinicians to gather a full picture of your child’s medical health and help them decide on an individualized care plan.
Treatment for SEDc varies because the condition affects several body systems, and each child’s case is different. Some children will only require careful monitoring. Others will need non-surgical or surgical treatments to address specific aspects of their condition.
At Children’s Hospital of Philadelphia, we practice collaborative, family-centered care. A team of expert clinicians — including leading orthopaedic surgeons and physicians, pediatric nurses, physical and occupational therapists, psychologists and other specialists — will partner with you in the care of your child.
Many children with SEDc are also diagnosed with a variety of orthopaedic conditions including: scoliosis, coxa vara, foot anomalies and joint problems. In many cases, these conditions only become evident — or problematic — as your child grows.
Depending on your child’s needs, specialists from the Spine Program, Hip Disorders Program, and Leg and Foot Program will treat your child’s orthopaedic and musculoskeletal issues.
Children with other effects of SEDc will be examined and treated by CHOP specialists in genetics, gastroenterology, general surgery, neurology, ophthalmology (eye), otolaryngology (ear, nose and throat) and plastic surgery.
For effects of SEDc, treatment may include:
- Bracing and/or surgery for spine issues
- Bracing and/or surgery for hip disorders
- Bracing and/or surgery for neck instability
- Bracing and/or surgery for knee instability and foot anomalies
- Staged reconstructive surgery for craniofacial disorders
- Glasses for vision problems.
- Hearing aids for hearing issues; tubes to reduce ear infections
- Medication or pain relievers for joint pain
- Physical therapy to help your child remain limber
Your child with spondyloepiphyseal dysplasia congenita should be monitored by an orthopaedic physician throughout her development, into adulthood.
Doctors will watch for spine, hip and knee instability, degenerative joint disease and joint pain. It is not uncommon for children with SEDc to need surgery during adolescence to treat spine or hip anomalies. Gait issues and neck instability may require some children with SEDc to limit walking and instead use a wheelchair.
If your child had spine, hip or foot surgery, she will need to see the orthopaedic surgeon about one to two weeks after surgery, then again at three and six months post-surgery. After that, annual monitoring by trained clinicians is strongly encouraged to ensure any problems are spotted and treated as soon as possible.
Additionally, physicians may recommend your child see several specialists because other body systems may be affected by SEDc.
For example, your child may see:
- An orthopaedist for any bone-, muscle- and joint-related issues
- Physical therapists and occupational therapists to expand your child’s physical dexterity and skill
- A neurologist or neuromuscular specialist to address any nerve or muscle weakness
- An ophthalmologist for vision issues
- An otolaryngologist for hearing loss, cleft palate or frequent ear infections
- A pulmonologist to monitor lung function, breathing and sleep issues
- A psychologist or social worker to address any body-image and related mental health issues
During follow-up visits, X-rays and other diagnostic testing may be done. The goal of continued monitoring is to help spot any irregularities in growth or development and to address health issues as they develop.
Follow-up care and ongoing support and services are available at our Main Campus and throughout our CHOP Care Network. Our team is committed to partnering with parents and referring physicians to provide the most current, comprehensive and specialized care possible for your child.
People with SEDc live a normal life span and have normal intelligence.
Because children with spondyloepiphyseal dysplasia congenita often have unstable necks, many activities are not recommended. Your doctor will give you a list of low-impact activities your child can do.
If you have questions about how your child’s condition and any related health issues may affect your child’s prognosis or long-term goals, talk to your child’s healthcare provider.