Characterization of idiopathic scoliosis in a clinically well-defined population

Idiopathic scoliosis is a highly prevalent disorder, familial in nature, wi th marked clinical variability. The purpose of this study was to characteri ze idiopathic scoliosis in a large series of families to be used for a geno me-wide search. One hundred thirty-one multigenerational families (892 indi viduals) with at least two affected individuals were studied. Data obtained included curve pattern, treatment, and back pain. Maximum curvature as a c ontinuous variable was evaluated using t tests for dichotomous characterist ics and linear correlation for continuous variables. An analysis of familia l loading was done. Four hundred forty-four individuals were classified as affected (82% female; 18% male). The right thoracic and left lumbar curves had the highest mean curvature (49 degrees). Mean curve size was greater in individuals with back pain. Back pain was most prevalent in the right thor acic and left lumbar curve pattern. The Pearson correlation coefficient bet ween the number of affected family members and the maximum degree of curvat ure was 0.16, suggesting that the greater the lateral curvature, the higher the proportion of family members affected with scoliosis. The sample popul ation is consistent with those of previous studies in relation to gender an d curve size. Statistically, the familial nature of this disorder is suppor ted.