Photosensitivity in a patient with C9orf72 repeat expansion

Does epilepsy contribute to the clinical phenotype of C9orf72 mutation in fronto-temporal dementia?

C9orf72 mutation is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) worldwide. Recently, several reports of patients with FTD who carried the C9orf72 mutation and also manifested epilepsy have been published, since seizures occur in FTD at a higher rate than in the general population, the possible association between epilepsy and C9orf72 mutation remains to be clarified. In the attempt to understand whether epilepsy contributes to the phenotype of the C9orf72 mutation, we compared epilepsy occurrence in patients with FTD who carried the C9orf72 mutation and those who did not. In our sample of 84 patients with FTD, 7.1% of cases reported epilepsy, with no significant differences between subsamples of patients with FTD stratified according to the presence of the C9orf72 mutation or to family history of FTD/parkinsonism/motor neuron disease. Our findings did not support to the possibility that epilepsy represents a characteristic feature of the C9orf72 mutation, as suggested by recent case reports published in the English literature.

Early juvenile reading epilepsy and later frontotemporal dementia (FTD): expanding the clinical phenotype of C9ORF72 mutation?

C9orf72 mutation (C9⁺) is a common genetic cause of frontotemporal dementia and amyotrophic lateral sclerosis. C9⁺ clinical phenotype is heterogeneous and epilepsy has been recently described in few cases. We report a 47-year-old patient who developed reflex reading epilepsy (RRE) at the age of 19. After the first years with exclusive reflex seizures, afterwards the patients developed drug-resistant, unprovoked seizures and progressive cognitive deterioration. In the last years, a progressive motor impairment with spastic tetraparesis also occurred. During the hospitalization, the patient underwent an extensive workup identifying C9⁺ expansion and a family history suggestive for an autosomal dominant inheritance. This report, together with the few cases already described, raises the possibility that epileptic manifestations are part of the clinical phenotype of C9ORF72 mutation and reflect hyperexcitability of cortical networks involved in neurodegeneration.

Timing and significance of pathological features in C9orf72 expansion-associated frontotemporal dementia

SEE SCABER AND TALBOT DOI101093/AWW264 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: A GGGGCC repeat expansion in C9orf72 leads to frontotemporal dementia and/or amyotrophic lateral sclerosis. Diverse pathological features have been identified, and their disease relevance remains much debated. Here, we describe two illuminating patients with frontotemporal dementia due to the C9orf72 repeat expansion. Case 1 was a 65-year-old female with behavioural variant frontotemporal dementia accompanied by focal degeneration in subgenual anterior cingulate cortex, amygdala, and medial pulvinar thalamus. At autopsy, widespread RNA foci and dipeptide repeat protein inclusions were observed, but TDP-43 pathology was nearly absent, even in degenerating brain regions. Case 2 was a 74-year-old female with atypical frontotemporal dementia-motor neuron disease who underwent temporal lobe resection for epilepsy 5 years prior to her first frontotemporal dementia symptoms. Archival surgical resection tissue contained RNA foci, dipeptide repeat protein inclusions, and loss of nuclear TDP-43 but no TDP-43 inclusions despite florid TDP-43 inclusions at autopsy 8 years after first symptoms. These findings suggest that C9orf72-specific phenomena may impact brain structure and function and emerge before first symptoms and TDP-43 aggregation.

Epilepsy and electroencephalographic abnormalities in C9orf72 repeat expansion

A patient has been recently described with frontotemporal cognitive decline and C9orf72 repeat expansion who presented abnormally slowed background and photoparoxysmal response at electroencephalographic (EEG) recording. Our data, based on five patients with repeat expansions in C9orf72 and EEG recordings suggest that abnormally slowed background and epilepsy represent previously unrecognized features of the C9orf72 phenotype in some patients.