Idiopathic scoliosis (IS) is a spine deformity of unknown etiology. Family studies have suggested that IS may be inherited as a mendelian autosomal dominant trait. We have performed linkage analysis on a three-generation IS Italian family. A positive LOD score value of 3.20 at theta=0.00 was detected with marker D17S799 after a genome-wide scanning. Analysis of six flanking microsatellites confirmed the linkage and haplotype inspection defined an interval of about 20 cM between D17S947 and D17S798. This is the first locus reported for IS. We scored genes mapping in this interval and studied the heparan sulfotransferase genes as candidates on the basis of their biochemical role. No causative mutation was detected in the affected patients.