Frontotemporal dementia with a C9ORF72 expansion in a Swedish family: clinical and neuropathological characteristics.

BACKGROUND In 2011 the C9ORF72 repeat expansion was identified as the most frequent genetic mutation underlying FTD and ALS. The main aim of this study was to investigate clinical characteristics in a large C9ORF72-positive FTD family, and to compare these with the neuropathological findings. METHODS The clinical records of 12 related FTD patients were thoroughly evaluated. The five neuropathologically examined cases were revised using additional TDP-43 immuno-stainings. Four cases were screened for the C9ORF72 expansion. RESULTS All 12 patients fulfilled the criteria for bvFTD. Restlessness and social neglect were often among the first reported symptoms. Psychotic symptoms were reported in 8 patients. Somatic complaints were seen in 7 cases. All the neuropathologically examined cases were TDP-43 positive. CONCLUSIONS The phenotype of this C9ORF72 hexanucleotide expansion carrier family was bvFTD. The clinical symptom profile was strikingly homogenous. Psychotic symptoms and somatic complaints were observed in most of the cases.