PHACTR1-associated fibromuscular dysplasia presenting with extensive carotid artery dissection in a young patient with ischemic stroke: a case report

Abstract Background Ischemic stroke in young adults poses a diagnostic challenge that requires evaluation of both conventional and non-conventional risk factors, including genetic and structural vascular diseases such as fibromuscular dysplasia (FMD). Case presentation We report the case of a 41-year-old patient with a previous ischemic stroke who presented with three days of progressive, pulsatile, holocranial headache without associated nausea or photophobia. Neurological examination revealed right lower limb monoparesis and hyperreflexia. Neuroimaging demonstrated an extensive left carotid artery dissection extending from its origin to the anterior communicating artery segment, along with irregularities in the vertebral and contralateral carotid arteries, consistent with FMD. Genetic testing identified a PHACTR1 gene mutation. Conclusions This case highlights fibromuscular dysplasia as an important cause of ischemic stroke in young adults and illustrates an unusually extensive arterial dissection associated with a PHACTR1 genetic variant. These findings support a genetically mediated vascular susceptibility spectrum and emphasize the importance of early recognition of non-atherosclerotic arteriopathies to guide diagnostic evaluation, individualized management, and secondary prevention.