ABSTRACT NUMBER: ESOC2026A1270 ISCHAEMIC STROKE IN MYOTONIC DYSTROPHY TYPE 1 WITHOUT CONVENTIONAL RISK FACTORS

Abstract Background and aims Myotonic dystrophy (DM1) is an autosomal dominant disorder mostly caused by CTG repeats in the DMPK gene, affecting skeletal and smooth muscles. Although cardiac involvement is common, stroke is uncommon and typically associated with cardiomyopathy or atrial arrhythmias. We highlight a case of myotonic dystrophy and ischaemic stroke in a patient with genetically confirmed DM1 in the absence of vascular risk factors. Methods A 41-year-old man with history of falls presented with transient right leg weakness. There was bilateral foot drop, myotonic grip, and frontal balding; his mother also had myotonia. Stroke workup, genetic testing and electromyography was performed. Care was delivered via a multidisciplinary team. Results CT brain was unremarkable and CTA revealed no stenosis. MRI confirmed acute left pontine infarction and atypical white matter disease with increased signal intensity noted in the outer aspect of the temporal lobes bilaterally. Echocardiography with bubble study showed no PFO. Cardiac monitoring showed sinus rhythm with first-degree AV block. Blood tests including autoimmune and thrombophilia screens were unremarkable. Electromyography showed myotonic discharges. Genetic testing confirmed pathogenic CTG repeat in the DMPK gene, consistent with DM 1. Conclusions This case highlights the rare association between DM1 and ischemic stroke. Despite an extensive negative stroke work-up, a neuromuscular disease was identified. This report shows the importance of considering myotonic dystrophy as a potential risk factor for stroke, the importance of family history and clinical examination. Conflict of interest Mergani Abdelwhab: Nothing to disclose.