Spinal deformities in hereditary motor and sensory neuropathy - A retrospective qualitative, quantitative, genotypical, and familial analysis of 175 patients

Study Design. Retrospective study of 175 patients with hereditary motor and sensory neuropathy (HMSN), i.e., Charcot-Marie-Tooth (CMT) disease. Objective. To investigate the frequency, age of onset, character, familial, and genotypical incidence of spinal deformities among HMSN patients. Summary of Background Data. Prior studies addressing HMSN discuss the associated spinal deformities. However, these data vary significantly while inconsistently including genotypes within the classification framework. Methods. Plain-film radiographic spine studies of 175 HMSN patients were performed to determine the incidence, character, and severity of spinal deformity. The degree of the spinal deformity was evaluated measuring Cobb's angle of the main curve. The results of the entire cohort were initially assessed before being classified by genotype. Results. The incidence of spinal deformity for the entire group was 26%. Of these, 58% demonstrated scoliosis, 31% had kyphoscoliosis, and 11% had thoracic hyperkyphosis; 73% of patients with spinal deformity were classified as HMSN Type I with confirmed duplication of the PMP 22 ( peripheral myelin protein) gene on chromosome 17. The incidence of spinal deformity by genotype was: duplication of the PMP 22 gene: 29% (25 of 87); deletion of the PMP 22 gene: 0% (0 of 15); Cx32 (connexin 32) gene mutation: 24% (8 of 34); and MPZ ( myelin protein zero) gene mutation: 100% (6 of 6). Familial incidence of spinal deformity was found in "MPZ gene mutation" and "duplication of PMP 22 gene" subgroups. Conclusion. This study demonstrates a 26% incidence of spinal deformity among HMSN patients. Spinal deformity was most frequently observed in patients with the MPZ gene mutation, where the most common familial incidence was also found.