Author Affiliations: Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, England.
We are grateful for the interest expressed by Silvestri and colleagues in our recent description of 2 siblings with an undiagnosed but presumed autosomal recessive spastic ataxia, who were found to harbor novel compound heterozygote mutations in the SACS gene.1 As pointed out in our original article, we appreciate that some of the features we observed within the brother and sister fell within the previously described clinical spectrum associated with mutations in this gene.1,2 However, onset in adult life is unusual, and a prominent sensorimotor neuropathy resembling Charcot-Marie-Tooth disease is not usually found.3 Thus, SACS is not the first disease gene that comes to mind for the family we described.1
Pyle A, Horvath R, Chinnery PF. Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay in the Time of Next-Generation Sequencing—Reply. Arch Neurol. 2012;69(12):1661-1662. doi:10.1001/2013.jamaneurol.389