Late-onset familial amyloid-polyneuropathy (FAP) Val30Met without family history

Abstract

Familial amyloid polyneuropathy (FAP) is rare and most commonly caused by the Val30Met mutation of the transthyretin (TTR) gene. Beside polyneuropathy, other complications due to amyloid deposits occur, but may vary in phenotype. The mutation tends to occur in endemic clusters. We describe a 65-year-old man from a non-endemic FAPVal30Met area who developed a progressive generalized painless axonal sensorimotor polyneuropathy with mild autonomic involvement and absent FAP symptoms in the family. Nerve biopsy showed amyloid deposits, staining with TTR-antibodies on immunohistochemistry.After DNA-sequencing of the TTR gene, the diagnosis of FAP Val30Met was made. Late-onset FAP Val30Met is a progressive and fatal disorder with varying penetrance, and may occur in non-endemic areas and cases without a family history. © 2008 Marshfield Clinic.