PO095 Utility of ataxia gene panel testing in irish inherited ataxia cases

Inherited ataxias are heterogeneous neurodegenerative disorders in which diagnostic evaluation is often challenging. The success in obtaining a diagnosis increases with evaluation at dedicated ataxia clinics with comprehensive clinical assessment, appropriate genetic evaluation and the use of next generation sequencing (NGS) techniques. Forty-eight genetically undiagnosed patients with early or late-onset ataxia were tested using NGS gene panels. Forty six percent were male, average age was 52.9 years. Most were sporadic cases (67%), half of them adult-onset. Of the familial cases, 56% had late symptom onset. Definite genetic diagnosis was obtained in 17 patients (35.4%), an impressive yield given the heterogeneity of cerebellar ataxias. In addition, potentially pathogenic compound heterozygous variants were found in three patients, a novel variant in a dominant gene in four cases and a single heterozygous variant in a recessive gene that could potentially explain the phenotype in 7 cases. A commercial NGS panel approach has increased the rate of positive genetic results where traditional methods were unsuccessful. NGS in genetically undetermined ataxia patients has delivered new diagnostic potential, providing a diagnosis in more than one-third of patients in our cohort; higher than in other published cohorts.