Scoliosis Medical Association" (2003) asserted the lifelong physical health, including cardiopulmonary and neurological functions, and mental health of idiopathic scoliosis patients are comparable to those of the general population. Scoliosis that interferes with normal systemic functions is "exceptional" and "rare", and "untreated [scoliosis] patients had similar death rates and were just as functional and likely to lead productive lives 50 years after diagnosis as people with normal spines". In an earlier University of Iowa follow-up study, 91 percent of idiopathic scoliosis patients displayed normal pulmonary function, and their life expectancy was 2% longer than that of the general population. Generally, the
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