GRN mutation in a patient with a behavioral variant of frontotemporal lobar degeneration (bvFTD)

The clinical spectrum of frontotemporal lobar degeneration (FTLD) is characterized by personality changes, language impairment, and executive function deficits. About 40% of FTLD cases have a family history of the disease, and the GRN gene is currently the most frequent genetic determinant. In cases of inherited FTLD with GRN mutations, parkinsonism is often an early sign due to greater grey matter atrophy in the caudate nucleus and bilateral atrophy in the thalamus. We investigated a female patient with signs of frontotemporal lobe atrophy and unilateral caudate nucleus atrophy on MRI. DNA was isolated from peripheral blood leukocytes and tested for GRN gene mutations. A pathogenic splice donor site mutation, c.708+1G>A, was found in the GRN gene. MRI showed unilateral caudate nucleus atrophy. This report extends the evidence for phenotypic and neuropathological heterogeneity in FTLD spectrum disorders due to splicing mutations in the GRN gene. .