Table 1_PRNP D178N-129MM prion disease: Creutzfeldt-Jakob disease-like cortical ribboning without prominent early insomnia.docx

Background<p>The PRNP p.Asp178Asn (D178N) mutation on a methionine-bearing codon-129 allele is classically associated with fatal familial insomnia (FFI), but some carriers develop a Creutzfeldt-Jakob disease (CJD)-like phenotype.</p>Case presentation and findings<p>We report a 59-year-old woman with two months of rapidly progressive cognitive-language decline, caregiver-observed nocturnal sitting-up and sleep talking, weight loss, extensive cortical diffusion-weighted imaging (DWI) ribboning, positive cerebrospinal fluid 14–3-3, and positive multisite skin real-time quaking-induced conversion.

Electroencephalography showed diffuse slowing without periodic sharp-wave complexes. PRNP sequencing identified D178N with methionine homozygosity at codon 129. A focused literature review identified six previously reported individual D178N-129MM cases with prion-compatible cortical or cortical-striatal DWI abnormalities.