Congenital scoliosis in monozygotic twins. Genetically determined or acquired in utero?

The term "congenital scoliosis" contributes little to our understanding of aetiology, for "congenital" simply means "to be born with" and is applicable to deformities present at birth whether these are genetically determined or acquired in utero. The presentation of monozygotic twins, one of whom has congenital scoliosis (vertebral anomalies) while the other is normal, provides a rare opportunity to study the cause of this deformity. Three pairs of monozygotic twins, previously unreported, are presented with a review of the previous literature. These cases add weight to the argument that congenital scoliosis may be acquired in utero rather than being genetically determined.