Abstract
Early-onset Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the development of amyloid plaques and neurofibrillary tangles at an earlier age. It affects multiple cognitive domains, including memory, executive function, and motor abilities. Here, we present a case of atypical early-onset AD. A 33-year-old woman with no significant medical history experienced a two-year decline in cognitive function, resulting in job loss and incidents such as cooking-related fires. Neurological examination revealed impaired attention, myoclonus, hyperreflexia, and a dystaxic gait. Imaging and tests showed minor abnormalities, with normal cerebrospinal fluid (CSF), genetic, autoimmune, and metabolic workups. Brain magnetic resonance imaging (MRI) and positron emission tomography (PET) fluorodeoxyglucose (FDG) scans indicated cortical atrophy and parietal hypometabolism. The patient was referred to a memory center for further evaluation and potential treatment with lecanemab. This case highlights the challenges in diagnosing early-onset neurodegenerative disorders, which can present atypically and mimic other conditions. The extensive diagnostic workup emphasizes the difficulty of diagnosing these disorders, particularly in the absence of specific biomarkers. Early diagnosis of neurodegenerative disorders in young adults requires heightened clinical suspicion and a comprehensive diagnostic workup, including advanced brain imaging, such as MRI and PET scans, to ensure timely diagnosis and referral to specialized centers.