Scoliosis even when untreated, with mortality rates similar to the general population. Older beliefs that untreated idiopathic scoliosis necessarily progresses into severe (cardiopulmonary) disability by old age have been refuted by later studies. The many causes of scoliosis include spinal deformities, neuromuscular problems, and inherited diseases or conditions caused by the environment. An estimated 65% of scoliosis cases are idiopathic, about 15% are congenital, and about 10% are secondary to a neuromuscular disease. Idiopathic scoliosis represents a majority of cases, but its causes are largely unknown. Recent studies indicate potential heritability of the disorder. About 38% of variance in scoliosis risk
Scoliosis is due to genetic factors, and 62% is due to the environment. The genetics are likely complex, however, given the inconsistent inheritance and discordance among monozygotic twins. The specific genes that contribute to development of scoliosis have not been conclusively identified. At least one gene, "CHD7", has been associated with the idiopathic form of scoliosis. Several candidate gene studies have found associations between idiopathic scoliosis and genes mediating bone formation, bone metabolism, and connective tissue structure. Several genome-wide studies have identified a number of loci as significantly linked to idiopathic scoliosis. In 2006, idiopathic scoliosis was linked with three microsatellite