Material and Methods
Patient was seen under a research protocol approved by the institutional ethical committee of Faculté de Médecine et d’Odonto-stomatologie (FMOS), Mali. The patient was examined by a multidisciplinary team including neurologist, ophthalmologist, cardiologist and ENT specialist after giving an informed consent. Brain MRI, nerve conduction study, and blood chemistries including vitamins B12 and E, blood glucose and blood cell counts were performed to consolidate our diagnosis and to exclude other ataxia causes. DNA was extracted from peripheral blood in the patient for genetic testing. Genetic testing was done by Athena Diagnostics in Marlborough, Massachusetts, USA.
Direct testing for the repeat expansion mutation in the FXN gene was performed by PCR amplification of the repeat region followed by high-resolution electrophoresis to determine the number of tandem repeats in each allele. Southern blot analysis was used, as necessary, to confirm homozygosity of normal alleles and to verify the number of repeats in highly expanded alleles. Southern blot analysis is performed using Bsi HKA restriction digestion of genomic DNA and hybridization with a gene specific probe. This methodology is greater than 99% accurate for the detection of repeat expansion mutations.