Bertolotti Syndrome in Children

About one in ten Australians who have lumbar X-rays has a lumbosacral transitional vertebra. The anatomy is present at birth: the lumbosacral border is set in the embryo by genes that have been studied for thirty years, the trait is heritable in animals, three human loci have been identified, and it runs in families without following a rule. In children it is silent in early life, tethers the growing spine, and in a minority becomes painful from the teens onwards, when it is called growing pa…