A clinical and epidemiological prevalence study on Friedreich’s Ataxia in Latium, Italy

Objective: To estimate the Fredreich's ataxia (FRDA) prevalence in a highly populated region of Italy (previous studies in small geographic areas gave a largely variable prevalence), and to define the patients' molecular and clinical characteristics. Methods: For the point-prevalence study we considered patients belonging to families with a molecular diagnosis of FRDA and resident in Latium on 1 January 2019. The crude prevalence of FRDA, specific for age and sex, was calculated and standardizing for age using the Italian population. Moreover, we investigated possible correlations among patients' genetic profile, symptoms and age of onset. Results: We identified 63 FRDA patients; the crude prevalence for total, males and females was 1.07 (95%CI 0.81-1.37), 0.81 (95%CI 0.54-1.22) and 1.32 (95%CI 0.97-1.79), per 100,000. We divided FRDA patients by three age-at-onset groups (early-EOFA 73%; late-LOFA 11.1%; very late-VLOFA 15.9%), and found significant differences in the scale for the assessment and rating of ataxia (SARA; p=0.001), a biased distribution of the shorter allele (p=0.001), an excess of scoliosis and cardiomyopathy (p=0.001) in EOFA. To determine the contribution of patients' molecular and clinical characteristics to the annual rate of progression, we performed a multivariate regression analysis that gave an R2 value of 45.3%. Conclusions: We estimated the crude and standardized prevalence of FRDA in Latium. A clinical classification (EOFA, LOFA, VLOFA) gave significant correlations. This epidemiological estimate allows to monitor a disease prevalence over time in cohort studies, and/or for developing disease registry.