A case of Gerstmann-Sträussler-Scheinker disease with a novel six octapeptide repeat insertion

Gerstmann-Straussler-Scheinker (GSS) disease is a rare inherited neurodegenerative disease due to a mutation in the prion protein (PRNP) gene, resulting in dementia and/or ataxia associated with mandatory amyloid plaques visible in the cerebral and/or cerebellar cortices on specimens stained with haematoxylin-eosin. Such amyloid plaques are dichroic in polarized light after Congo red staining and well marked by immunohistochemistry to prion protein (PrP). Almost every GSS family carries a PRNP missense mutation and almost half of them are due to a P102L mutation present in the original Austrian family [1], and also in a large family from central England [2–4]. GSS cases were also reported with a P105L mutation in Japan [5], with an A117V mutation in French-Alsacian [6], American [7] and English [8] families, and with a F198S mutation in the Indiana Kindred [9]. Other rare mutations have briefly been reported [3]. Three GSS cases due to an octapeptide repeat insertion (OPRI) in their PRNP between codons 51 and 91 [3] have also been investigated, eight in two unrelated French families [10– 13] and seven in a Dutch family [14]. We report here a French case with a novel six OPRI.