In 80% of patients, the cause of scoliosis is unknown. Such cases are called Idiopathic Scoliosis.
It is thought to 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.
Researchers have not been able to identify the specific genetic abnormalities that make a young person susceptible to spinal distortion. Inherited physical abnormalities, problems in coordination, abnormalities in the central nervous system, and other inherited factors may play some role either alone or in combination with other conditions to produce Scoliosis.
Researchers are investigating possible physical abnormalities that may cause imbalances in bones or muscles that would lead to scoliosis. Among them are the following:
Imbalances in muscles around the Vertebrae. Some research suggests that imbalances in the muscles around the vertebrae may make children susceptible to spinal distortions as they grow.
One study showed a higher incidence of abnormally high arches in the feet in people with Idiopathic Scoliosis, suggesting that altered balance may be a factor in certain cases.
Some experts are looking at inherited defects in perception or coordination that may cause asymmetrical growth in the spine of some children with Scoliosis.
Genetic Abnormalities in the Central Nervous System. Genetic defects that cause altered processing in the brain may play a role in producing abnormalities in the growing spine. For example, interesting research has implicated low levels of melatonin, a hormone secreted in the brain that is involved with sleep and growth.
Researchers speculate that genetic factors that cause reduced blood levels of melatonin may adversely affect muscle tone and development during sleep, perhaps contributing to Scoliosis.
A number of other biologic factors are being investigated for some contribution to Scoliosis:
In collagen, the critical structural protein found in muscles and bones. Enzymes known as matrix metalloproteinases are involved in the repair and remodeling of collagen. Researchers have found high levels of the enzymes in the disks of patients with Scoliosis, which suggests that the enzymes may contribute to curve progression. Elevated levels of the enzymes can cause abnormalities in components in the spinal discs, contributing to disc degeneration.
A possible defective gene responsible for production of fibrillin, an important component of connective tissue, which makes up bones and muscles.
Abnormalities in a protein called platelet calmodulin that binds to calcium.
Congenital Scoliosis is caused by inborn spinal deformities that may result in the development of absent or fused vertebrae. Kidney problems, particularly having only one kidney, often coincide with Congenital Scoliosis. The condition usually becomes evident at either age two or between ages eight and 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 five -- may be important in many of these patients to prevent serious complications.
Scoliosis may be a result of various conditions that affect bones and muscles associated with the spinal column. They include the following:
Diseases that can cause scoliosis are Marfan's syndrome, Friedreich ataxia, Albers-Schonberg disease, rheumatoid arthritis, Cushing's syndrome, and osteogenesis imperfecta.