Causes:

Until recently, researchers have not been able to identify any specific genetic abnormalities that make a young person susceptible to spinal distortion. The first gene clearly related to idiopathic scoliosis (scoliosis of unknown cause) was found at the conclusion of a 10-year study, the results of which were published in 2007. Variations in this gene, CHD7, can make people more susceptible to idiopathic scoliosis. It is still unclear how this gene affects a person's susceptibility.

Physical Abnormalities. Researchers are investigating possible physical abnormalities that may cause imbalances in bones or muscles that would lead to scoliosis. Among them are the following: Some research suggests that imbalances in the muscles around the vertebrae may make children susceptible to spinal distortions as they grow.

Problems in Coordination. Some experts are looking at inherited defects in perception or coordination that may cause unusual growth in the spine of some children with scoliosis.

Other Biological Factors. Several other biological factors are being investigated for some contribution to scoliosis:

• Elevated levels of the enzyme matrix metalloproteinases may cause abnormalities in components in the spinal disks, contributing to disk degeneration.
• Abnormalities in a protein called platelet calmodulin that binds to calcium. This protein acts like a tiny muscle and pulls clots together.

Idiopathic Scoliosis

In 80% of patients, the cause of scoliosis is unknown. Such cases are called idiopathic scoliosis. (Idiopathic means without a known cause.) Idiopathic scoliosis may be due to multiple, poorly understood inherited factors, most likely from the mother's side. However, the severity often varies widely among family members who have the condition, suggesting that other factors must be present.

Idiopathic scoliosis may be classified based on age of presentation. Age of onset may also determine the treatment approach. The classification is as follows:

• Infantile: Up to 3 years old
• Juvenile: Four to 9 years old
• Adolescent: Ten years old through the teen years

Idiopathic scoliosis may be initially diagnosed in adults during evaluation for other back complaints or disorders, although the curve is unlikely to be significant.

Congenital Scoliosis

Congenital scoliosis is caused by inborn spinal deformities that may result in absent or fused vertebrae. Kidney problems, particularly having only one kidney, often coincide with congenital scoliosis. The condition usually becomes evident at either age 2 or in children ages 8 - 13 as the spine begins to grow more quickly, putting additional stress on the abnormal vertebrae. It is essential to diagnose and monitor such curvatures as early as possible, since they can progress quickly. Early surgical treatment -- before age 5 -- may be important in many of these patients to prevent serious complications.

Neuromuscular Scoliosis

Neuromuscular scoliosis may result from a variety of causes, including:

• A traumatic spine injury
• Neurological or muscle disorders
• Cerebral palsy
• A traumatic brain injury
• Poliomyelitis (Polio)
• Myelomeningocoele (a hernia of the central nervous system)
• Spinal muscle dystrophy
• Spinal cord injuries
• Myopathies

These patients frequently have significant complications, including an increased risk for skin ulcers, lung problems, and significant pain.

Causes of Degenerative Lumbar Scoliosis in Adults

Adult scoliosis has two primary causes:

• Progression of childhood scoliosis.
• Degenerative lumbar scoliosis. Degenerative lumbar scoliosis is a condition that typically develops after age 50. With this condition, the lower spine is affected, usually due to disk degeneration. Osteoporosis, a serious problem in many older adults, is not a risk factor for new-onset scoliosis, but it can be a contributing factor. In most cases, however, it is not known why scoliosis occurs in adults.

Conditions That Affect the Spinal Column and Surrounding Muscles

Scoliosis may be a result of various conditions that affect bones and muscles associated with the spinal column. They include the following:

• Tumors, growths, or other small abnormalities on the spinal column. For example, syringomyelia, a disorder in which cysts form along the spine, can cause scoliosis. These spinal abnormalities may play a larger role in causing some cases of scoliosis than previously thought.
• Stress fractures and hormonal abnormalities that affect bone growth in young, competitive athletes.
• Turner syndrome, a genetic disease in females that affects physical and reproductive development.
• Other diseases that can cause scoliosis are Marfan syndrome, Aicardi syndrome, Friedreich ataxia, Albers-Schonberg disease, rheumatoid arthritis, Cushing syndrome, and osteogenesis imperfecta.

Spina bifida is a congenital disorder (present at birth) in which the backbone and spinal canal do not close before birth. In severe cases, this can result in the spinal cord and its covering membranes protruding out of an affected infant's back. Spina bifida may also be nearly inconsequential, or may be repairable through surgery.