A case series of hereditary cerebellar ataxias in a highly consanguineous population from Northeast Brazil

Background: There are few studies reporting characteristics of patients with cerebellar ataxias in the Brazilian population. The aim of this study was to provide a detailed neurological description of patients with hereditary ataxia followed by a neurology outpatient service in Brazil.

Methods: Neurological and clinical evaluation of patients with hereditary ataxia was performed at a neurology service outpatient clinic of a hospital in Northeast Brazil between October 2013 and January 2015.

Results: A total of 47 patients had ataxia as the main symptom. A high prevalence of consanguinity was found in the population studied (40.4%). Mean age was 38.4 ± 15.3 years, mean age at disease onset was 25.6 ± 17.3 years, mean disease duration was 12.8 ± 9.7 years, and mean score on the Scale for the Assessment and Rating of Ataxia (SARA) was 18.4 ± 7.7. Patients with recessive pattern of inheritance were younger, had earlier age at disease onset and greater severity of ataxia, measured by the SARA. Diagnosis was confirmed by molecular analysis, laboratory exams or biopsy in 42.56% (n = 20) of these patients. The most prevalent diseases were: Friedreich's ataxia in 35% (n = 7), Niemann-Pick type C (NPC) in 15% (n = 3), and ataxia with oculomotor apraxia type 2 in 15% (n = 3).

Conclusions: In contrast with other studies, our prevalence of recessive ataxias was much higher than that of dominant ataxias. These findings might be explained by the high number of patients living in rural areas with a higher rate of consanguineous marriages, absence of a dominant ataxia founder effect or difficult access to healthcare system.