Spondyloepiphyseal Dysplasia - Causes, Symptoms, Diagnosis, and Treatment

Introduction:

Dysplasia refers to the presence of abnormalities in the cells. The organs affected with dysplasia condition are unable to provide healthy cells for their normal functions. These abnormalities are not malignant in nature, but dysplasia is often considered to be a premalignant condition.

What Is Spondyloepiphyseal Dysplasia?

The word spondyl prefixes to any medical terminology that depicts the vertebra (backbones) and the epiphysis are the ends of the long bones in the limbs (arms and legs). Thus, spondyloepiphyseal dysplasia refers to the group of skeletal disorders involving the bones of the limbs and the spine (vertebra). Typically, the condition is characteristic of underdevelopment or fragmentation in the ends of the long bones or the vertebra.

Spondyloepiphyseal dysplasia comes under the broad category of osteochondrodysplasia, specified by abnormal growth and remodeling of the cartilage and the bones.

What Are the Forms of Spondyloepiphyseal Dysplasia?

There are two main forms of spondyloepiphyseal dysplasia,

• Spondyloepiphyseal Dysplasia Congenita (SEDC): The short stature is evident at the time of birth.

• Spondyloepiphyseal Dysplasia Tarda (SEDT): The growth abnormalities are evident only when the child is five to ten years old.

What Are the Causes of Spondyloepiphyseal Dysplasia?

• Spondyloepiphyseal dysplasia is a congenital disorder (birth defect) resulting from the mutation of the COL2A1 gene.

• Genes command the creation of proteins for the purpose of various body functions.

• The body tissues are made of a copious amount of protein called collagen, which is the major component of cartilage, bones, skin, muscle, tendons, and ligaments.

• Collagens are classified into various types depending on their tissue distribution and function.

• The COL2A1 gene is responsible for the synthesis of type II collagen, which is mainly needed for the formation of cartilage and bone.

• Hence, mutation (variation) of the specific COL2A1 gene ultimately causes abnormalities in the skeleton resulting in spondyloepiphyseal dysplasia.

• Spondyloepiphyseal dysplasia is passed on to the child in an autosomal dominant pattern (one affected parent can pass on the gene to the child).

What Are the Signs and Symptoms of Spondyloepiphyseal Dysplasia?

The clinical features and the severity of spondyloepiphyseal dysplasia significantly varies between individuals. The child may not present with all of the symptoms, but the below list is often associated with spondyloepiphyseal dysplasia.

1) Growth and Developmental Disturbances:

Growth deficiency and short stature are the characteristic features, especially in spondyloepiphyseal dysplasia congenita. The body and the neck appear relatively short compared with the limbs. The affected individuals will reach a final maximum height of 4.2 feet during their adulthood. Club foot (twisted and deviated from its position), barrel chest (broad and deep chest), pectus carinatum (protruded chest bone), and limited extension of the limbs are also common findings.

2) Spinal Deformities:

Spinal abnormalities include,

• Kyphosis - Forward bending and rounding of the upper backbone.

• Scoliosis - Lateral curvature of the spine.

• Lumbar Lordosis - Inward curvature of the lower backbone.

• Cervical Instability - Subluxation of the vertebra in the neck region.

• Cervical Myelopathy - Increased instability possess the risk of a compressed spinal cord in the neck causing cervical myelopathy (pain and stiffness).

• Joint Disorders:

The most important joints of the body, like the knees, elbows, and hips, are affected by spondyloepiphyseal dysplasia. Rigidity and the loss of movement will develop. Some of the developmental findings are coxa vara and coxa valga (abnormal angulations in the hip joints). Knee deformities include genu varum (bow legs) and genu valgum (knock news).

The affected kids are more prone to develop painful inflammatory joint diseases (osteoarthritis) in the future.

3) Lung Manifestations:

Changes in the size of the rib cage (diminished or small) due to abnormalities in the development of the spine and chest bone prevent the lungs from filling the air during breathing. Thus, newborns with spondyloepiphyseal dysplasia will have breathing difficulties which will eventually wane off as the kids grow. But, few may have persistent respiratory infections and sleep apnea (paused breathing during sleep).

4) Neurological Defects:

Skeletal dislocation may cause sciatica which refers to pain, numbness, and tingling sensation in the lower back extending through the leg because of the compression of the sciatic nerve.

5) Muscular Atrophy:

Decreased muscle mass and generalized weakness make the children exhibit delay in normal milestones like crawling and walking.

6) Facial and Oral Features:

A cleft palate (split in the roof of the mouth), malar hypoplasia (underdevelopment of the cheekbone), hypertelorism (increased distance between the eyes), and a flat face may be seen.

7) Eye Abnormalities:

Myopia (nearsightedness), eye floaters, retinal degeneration, and retinal detachment will develop gradually in spondyloepiphyseal dysplasia.

8) Auditory Defects:

Deformity in the inner ear and defect in the auditory nerve (which connects the inner ear with the brain) will progressively lead to hearing loss.

How to Diagnose Spondyloepiphyseal Dysplasia?

Spondyloepiphyseal dysplasia congenita can be diagnosed with its characteristic features, family history, and detailed physical examination of the child after birth. Other clinical testings involved are,

Imaging Studies:

Basic X-rays can show gross abnormalities in the skeleton. Further advanced imaging modalities like computed tomography (CT) and magnetic resonance imaging (MRI) will illustrate detailed bone deformities for precise delineation of affected structures prior to surgical intervention.

Genetic Testing:

Single gene testing or molecular genetic testing will help to identify the specific mutated gene responsible for spondyloepiphyseal dysplasia congenita.

How to Treat Spondyloepiphyseal Dysplasia?

Symptomatic and supportive treatments are effective in treating patients with spondyloepiphyseal dysplasia.

• Genetic counseling, along with psychosocial support, is essential for the family members of the affected child.

• Periodic eye and ear examinations are required to prevent the complete loss of eyesight and hearing. Surgery may be needed for correct retinal detachments.

• Breathing difficulties are to be detected earlier, and supportive care is provided to ensure clear respiration.

• Painkillers and muscle relaxants to relieve pain. Physical therapy and exercises may reduce joint stiffness and improve their range of motion. Surgery will be required if there is any severe dislocation in the joints.

• Regular stretching and strengthening exercises will prevent muscle wasting (atrophy).

• Developmental defects like clubfoot, bow knees, knock knees, etc., are managed with splints or orthotic braces.

• Spinal deformities and cervical instability are corrected by spinal fusion surgery.

Conclusion:

Several complications are associated with undiagnosed and untreated spondyloepiphyseal dysplasia. The parents or caregivers must be completely educated regarding the condition and the risk factors. Spondyloepiphyseal dysplasia does not reduce life expectancy and cognitive behavior. Hence, by only treating physical abnormalities associated with spondyloepiphyseal dysplasia with supported care, the patients can lead a normal productive life.