A novel heterozygous GRN deletion (c.302_315del) associated with behavioral variant frontotemporal dementia.

We present the case of a 64-year-old woman who was evaluated for progressive behavioral and cognitive decline. Her clinical presentation was characterized by marked personality changes, apathy, and disinhibition, accompanied by irritability, executive dysfunction, and memory impairment. Neuropsychological assessment revealed significant cognitive impairment, with a Mini-Mental State Examination (MMSE) score of 14 and a Montreal Cognitive Assessment (MoCA) score of 11. Brain MRI revealed prominent asymmetric fronto-temporo-parietal atrophy, worse on the right. A heterozygous pathogenic granulin (GRN) mutation (c.302_315del) was identified via whole-exome sequencing and was also found in one of her sons. This case expands the mutational spectrum of GRN and underscores its diagnostic relevance in behavioral variant frontotemporal dementia (bvFTD).