Early-onset ataxia with progressive external ophthalmoplegia associated with POLG mutation: autosomal recessive mitochondrial ataxic syndrome or SANDO?

Autosomal recessive ataxias caused by mutations of the polymerase γ (POLG) gene make an important group of progressive ataxias accompanied by a diverse spectrum of neurological disorders. Because the clinical picture can be quite miscellaneous, it is challenging to assort patients to any of the currently described syndromes; therefore, to provide such a patient with a conclusive diagnosis can be challenging for the neurologist. A typical magnetic resonance imaging finding is probably the most useful landmark in the diagnostic process, which will steer the clinician toward POLG gene testing. To illustrate this, we present a case of progressive ataxia caused by A467T and W748S mutations of POLG gene, who presented with overlapping symptoms of autosomal recessive mitochondrial ataxic syndrome and SANDO, as well as choreoathetotic movements and dysphonia. After lengthy investigations, magnetic resonance imaging showed T2 and FLAIR hyperintensities in the thalamus, inferior olives, and cerebellum, which led us to the analysis of POLG mutations.