Behavioral and Personality Changes as the First Manifestation of Spinocerebellar Ataxia Type 2.

Background. Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disorder caused by CAG repeat expansion in the ATXN2 gene. Although classically characterized by progressive cerebellar ataxia and oculomotor abnormalities, increasing evidence indicates that SCA2 is a multisystem disorder with prominent cognitive, behavioral, and psychiatric manifestations. These non-motor symptoms may precede overt motor signs, leading to diagnostic challenges and misdiagnosis as primary psychiatric conditions. Case Presentation. We report the case of a 59-year-old man with a several-year history of progressive behavioral and emotional dysregulation, initially diagnosed as a personality disorder. Prominent features included irritability, impulsivity, disinhibition, hypersexuality, altered eating behavior, and recurrent self-endangering suicidal gestures, with relatively preserved functional autonomy. Neurological examination revealed subtle cerebellar signs. Neuropsychological assessment showed impaired verbal memory with preserved recognition and borderline attentional–executive deficits, consistent with cerebello–frontal dysfunction. Brain magnetic resonance imaging (MRI) demonstrated moderate-to-severe cerebellar and brainstem atrophy, while dopamine transporter SPECT revealed severe bilateral presynaptic dopaminergic denervation. Cerebrospinal fluid biomarkers excluded Alzheimer’s disease. Genetic testing confirmed SCA2 with 38 CAG repeats in ATXN2. Conclusions. This case illustrates an atypical presentation of SCA2 in which behavioral and psychiatric symptoms preceded motor manifestations by several years. Recognition of such presentations is crucial to avoid misdiagnosis, reduce diagnostic delay, and enable timely genetic counselling and multidisciplinary management, reinforcing the concept of SCA2 as a multisystem neurodegenerative disorder.