Fatal familial insomnia

Clinical and pathologic features of a patient with fatal familial insomnia whose prion (PrP) genotype is D178N coupled with methionine at codon 129 on his mutant allele and valine on his normal allele are described and phenotypic heterogeneity of FFI is suggested.

Abstract

We describe clinical and pathologic features of a patient with fatal familial insomnia (FFI) whose prion (PrP) genotype is D178N coupled with methionine at codon 129 on his mutant allele and valine at codon 129 on his normal allele. A cousin (genetic half brother) with identical PrP genotypes exhibited strikingly different clinical and pathologic changes. Comparison of these cousins shows the phenotypic heterogeneity of FFI and suggests that the phenotypic expression of D178N is influenced by multiple factors.