Clinical and Genetic Study of Friedreich’s Ataxia and Ataxia with Vitamin E Deficiency in 44 Moroccan Families

Introduction: Friedreich ataxia (FRDA) is a multi-system autosomal-recessive disease, the most common one of the genetically inherited ataxias. FRDA occurs as a consequence of mutations in the frataxin gene, with an expansion of a GAA trinucleotide. Ataxia with vitamin E deficiency (AVED) is characterized clinically by neurological symptoms with often striking resemblance to those of Friedreich’s ataxia (FA) but serum concentrations of vitamin E are low. Aim of study: To study clinical and genetic features of the Friedreich’s ataxia and AVED patients in 44 Moroccan families. Patients and Methods: Retrospective series of 72 Moroccan patients displaying Friedreich’s ataxia syndrome was recruited over a period of 22 years (1987-2009). All patients had a clinical and ophtalmological examinations, 30 patients underwent electromyography, and CT scan was performed in 29 patients. GAA repeats in the frataxin gene and the 744 del A mutation α-TTP gene were performed in all patients. Results: 17 patients (24% of cases) had the 744 del A mutation in the α-TTP gene responsible of ataxia with vitamin E deficiency (AVED) phenotype. 55 patients (76% of cases) had GAA expanded allele in the first intron of the frataxin gene. Phenotype-genotype correlation revealed a high frequency of head titubation, decreased visual acuity and slower disease progression in AVED than in Friedreich’s ataxia phenotype (p < 0.05). Conclusion: Our study represents a large series which highlight the clinical and genetic differences between AVED and Friedreich’s ataxia. AVED patients have a better prognosis after alpha-tocopherol treatment.