Fatal familial insomnia: Reporting a case of the rare nightmare.

Prion diseases are rare, incurable, and rapidly progressive. Pathogenic misfolded proteins accumulate in the central nervous system causing fatal neurodegeneration. Fatal familial insomnia (FFI) is an even rarer, hereditary subset of prion disease. The initial clinical course is nonspecific, leading to difficulties with diagnosis. We describe a patient with a family history of prion disease who presented with early symptoms of FFI including disordered sleep, cognitive dysfunction, and autonomic dysregulation. Notably, diagnostic studies including magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) analysis, and electroencephalography (EEG) did not show changes characteristic of prion disease. However, genetic testing showed a pathological, heterozygous mutation c.532G> A (p.Asp178Asn), confirming FFI. His clinical course progressed rapidly, and death occurred several months after the initial hospital presentation. We discuss the pathophysiology and diagnosis of FFI and the emotional care required to treat this fatal disease. General practitioners should be aware of this rare diagnosis to improve patient management.