Posterior Spinal Fusion for Friedreich Ataxia-Related Scoliosis in Twin Girls

Abstract

Friedreich ataxia (FRDA) is an autosomal recessive spinocerebellar ataxia with an incidence of two in 100,000 Caucasians1. Caused by a triplet expansion mutation of the frataxin gene, which is located on chromosome 9q13, it is the most common recessively inherited ataxia2. Early symptoms include tabetocerebellar ataxia, generalized clumsiness, scoliosis, and pes cavus or equinovarus1,2. Later, dysarthria, nystagmus, hypertrophic cardiomyopathy, and diabetes mellitus may arise1. Symptoms begin within the first two decades of life, and most people with FRDA lose the ability to walk within fifteen years3. Cardiomyopathy may lead to arrhythmia, congestive heart failure, and premature death by the third or fourth decade4. Scoliosis has been reported in 63% to 100% of people with FRDA2,5-8. Curve classification is varied, with most now recognizing a neuromuscular pattern5-8. Bracing does not halt the progression of these curves and can further hinder mobility5-7, so surgical treatment is indicated7,8. A report in the recent literature demonstrated enhanced stability with use of segmental pedicle screw fixation7. Despite the familial nature of FRDA, there have been no reports, to our knowledge, of posterior spinal fusion in twins with FRDA-related scoliosis. We present the case of twin girls with FRDA and scoliosis. We highlight the similarity of phenotype in these twins, with respect to scoliosis curve type, onset, and progression, as well as the timing and success of surgical intervention. Both patients and their guardians were informed that data concerning their cases would be submitted for publication, and they all provided consent. Fourteen-year-old identical twin sisters with FRDA and scoliosis were referred to our center. Genetic testing showed homozygous mutation of the frataxin …