Validation of the RADIAL Algorithm for Diagnosis of Autosomal Recessive Cerebellar Ataxia

RADIAL is an algorithm which has been developed following a review of the literature on 67 autosomal recessive cerebellar ataxias (ARCA) and personal clinical experience. Frequency and specificity of each feature were defined for each autosomal recessive cerebellar ataxia, and corresponding prediction scores were assigned. Clinical and paraclinical features of patients are entered into the algorithm, and a patient's total score for each ARCA is calculated, producing a ranking of possible diagnoses. Sensitivity and specificity of the algorithm were assessed by blinded analysis of a multinational cohort of 834 patients with molecularly confirmed autosomal recessive cerebellar ataxia. The performance of the algorithm was assessed versus a blinded panel of autosomal recessive cerebellar ataxia experts. The correct diagnosis was ranked within the top 3 highest-scoring diagnoses at a sensitivity and specificity of \>90% for 84% and 91% of the evaluated genes, respectively. Mean sensitivity and specificity of the top 3 highest-scoring diagnoses were 92% and 95%, respectively. Our aim is now to validate in a prospective cohort of ARCA, the performance of RADIAL to predict the correct genetic diagnosis.