Scoliosis and Rett syndrome

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Our understanding of the rare progressive neuromuscular disorder associated with the name of Andreas Rett has advanced significantly in the last 20 years. This includes the consequences for the musculoskeletal system. What have we learned? Scoliosis is exceedingly common in Rett syndrome, developing in 50 to 90% of individuals with the condition. It often appears during juvenile growth, worsens rapidly during adolescence, and continues to progress in severity after skeletal maturation. In its more severe forms it can impair sitting and positioning, reduce pulmonary function, and cause pain. Like scoliosis associated with cerebral palsy, it occurs with greater frequency in individuals with more extensive developmental impairment, particularly when regression of skills is noted before 6 months of age and when walking is never achieved or is lost before maturation. Unlike cerebral palsy, the risk of scoliosis in Rett syndrome appears to be linked to specific chromosomal changes. Of the numerous mutations of the methyl-CpG-binding protein 2 gene (MECP2) at chromosome Xq28, two mutations (R294X and R306C) are known to be associated with milder developmental impairment and reduced risk for developing scoliosis.1, 2 Other mutations of MECP2 may be found to be associated with increased risk of severe developmental impairment and the formation of scoliosis. The study of Riise et al.3 affirms the link between more severe developmental impairment and increased risk of scoliosis. The authors also suggest that a link may exist between patterns of scoliosis in Rett syndrome and the severity of the developmental impairment. They found a tendency for individuals with more severe manifestations of Rett syndrome to have long single curves in which the pelvis acts as an end-vertebra, resulting in pelvic obliquity. Milder manifestations of Rett syndrome were associated with balancing double curves, usually of smaller magnitude. In Rett syndrome, physiotherapy is valued for encouraging flexibility, strength, and movement but therapy appears to have no effect on curve behavior. Spinal bracing slows the pace of curve progression but seems incapable of preventing the formation of large curves. Slowing the rate at which curves progress (and improving trunk shape and balance) has merit but braces can be difficult to wear. Successful spinal fusion surgery yields a smaller deformity and a more balanced trunk, and may improve pulmonary function and reduce pain. The result is appreciated by parents and other care providers but it is a complex technical procedure and a major physiological challenge that is prone to complications.4, 5 If future studies demonstrate a relationship between specific MEPC2 mutations and the risk for developing certain patterns of scoliosis or large, severe, curves then we, as clinicians, may be able to properly focus our worry and our interventions. For the group of patients prone to severe curves or curves associated with pelvic obliquity and poor sitting posture, spine fusion could be completed before the deformity necessitates both anterior and posterior surgical approaches, and before the general deterioration of health increases the risk of serious complications.6 For other patients, physiotherapy, bracing, and specialized seating arrangements could be employed as needed to assist in individual care.