Adult-onset Niemann–Pick disease type C: A diagnostic and therapeutic odyssey of a rare condition

Niemann–Pick disease type C (NPTC) is a rare, autosomal recessive disorder characterized by lysosomal lipid storage and progressive neurodegeneration. While NPTC typically presents in infancy or childhood, adult-onset cases pose significant diagnostic challenges due to their resemblance to common neuropsychiatric conditions. This case report describes a 34-year-old male presenting with inattention and forgetfulness, initially misdiagnosed with attention deficit and depression. His symptoms, including clumsiness and memory loss, were progressive over 8 years. Despite normal routine neurological examinations and non-specific findings on brain magnetic resonance imaging, the Neuropsychiatric Test Battery suggested organic factors affecting various cognitive functions. Genetic testing confirmed NPTC, and the patient was started on miglustat. This case underscores the importance of considering NPTC in the differential diagnosis of early-onset dementia and unexplained neuropsychiatric symptoms in adults. Early recognition and intervention with disease-modifying therapies like miglustat are crucial for improving patient outcomes. The case adds to the growing evidence that adult-onset NPTC is underrecognized and highlights the need for heightened clinical suspicion and comprehensive evaluation, including genetic testing, in patients with atypical neurological presentations.