Costello syndrome-associated orthopaedic manifestations focussed on kyphoscoliosis: a case series describing the natural course.

Costello syndrome (CS) is a rare genetic condition caused by a heterozygous mutation in the HRAS gene, with an estimated prevalence of 1: 300 000. Individuals with CS present with characteristic features including scoliosis, kyphosis, Chiari 1 malformation, and syringomyelia. The natural history of the spinal deformity associated with CS has been incompletely described. This case series describes the spinal deformity associated with CS and sets out a strategy for screening and treatment. The clinical records and spinal radiographs of nine consecutive CS patients encountered at a single centre were reviewed. Radiological assessments for the presence and progression of scoliosis were studied. Nine patients with confirmed CS were followed for a mean of 6.6 years. Five patients showed mild scoliosis. Two patients had lumbar kyphosis in addition to their scoliosis, and one showed scoliosis with proximal thoracic kyphosis. Three patients underwent investigation with MRI, one of which showed Chiari I malformation and a syrinx. One showed no change in the severity of their deformity over time. The remaining four patients showed a rate of increasing coronal deformity of 2.1° per year. There were no cases of rapid progression. All cases showed delayed skeletal maturity. The spinal deformity in CS appears to be slowly progressive. To identify those at risk of more rapid progression, brain and spine MRI should be carried out to exclude structural neurological abnormalities. Long follow-up is required for patients with spinal deformity in CS due to the delay in reaching skeletal maturity. Evidence level: 4.