SCOLIOSIS IN TWINS - A METAANALYSIS OF THE LITERATURE AND REPORT OF 6CASES

Study Design. This study is a meta-analysis of the world's literature on adolescent idiopathic scoliosis in monozygotic and dizygotic twins. Additionally, six previously unreported cases of scoliosis in twins a re presented. Objectives. To compare and contrast the concordance, sev erity, and curve patterns in monozygotic and dizygotic twins with adol escent idiopathic scoliosis in an attempt to document a genetic etiolo gy and delineate inheritance patterns for adolescent idiopathic scolio sis. Summary of Background Data, There are numerous case reports of tw ins sets with adolescent idiopathic scoliosis, However, this data has not been previously analyzed as a single data base. Methods. The liter ature was searched for cases of twins with adolescent idiopathic scoli osis, and six cases of patients treated by authors were added. One hun dred cases of sets of twins were discovered, 68 of which had sufficien t data for comparative analysis. Each set was evaluated for monozygosi ty, concordance of scoliosis, curve pattern, and severity of curve. Re sults. Thirty-seven sets of twins were monozygous, and 31 sets were di zygous. Concordance was 73% among monozygous twins and 36% among dizyg ous twins. The difference is statistically significant at P < 0.003. C urve severity could be compared in 20 sets of monozygous twins and 16 sets of dizygous twins. Among monozygous twins, there was a correlatio n coefficient of r = 0.399 (P < 0.126). Curve pattern comparison was n ot statistically significant. Conclusions. Monozygous twins have a sig nificantly higher rate of concordance than dizygous twins, and the cur ves in monozygous twins develop and progress together. Based on these data, there is strong evidence for a genetic etiology for adolescent i diopathic scoliosis.