A 57-Year-Old Male With Behavioral Variant Frontotemporal Dementia and MATR3 and NOS3 Mutations.

This report presents a case of behavioral variant frontotemporal dementia caused by mutations in the MATR3 and NOS3 genes, aiming to analyze its clinical manifestations and genetic characteristics. For a case presenting with personality changes and gait abnormalities as the initial symptoms, this study conducted a comprehensive analysis of its clinical manifestations, neuropsychological assessments, cerebrospinal fluid biomarkers, head imaging changes, and genetic test results. It also discussed the possible causes based on the literature. Its main manifestations include personality changes, gait disorders, and a decline in executive functions. 18F-FDG PET shows decreased FDG metabolism in both bilateral frontal lobes, temporal lobes, and anterior cingulate gyrus, accompanied by corresponding brain atrophy, and no abnormal deposition of Aβ in both cerebral hemispheres. The related gene detection indicates mutations in the MATR3 gene (NM_018834.6: intron 11: c.1778 + 3A > G) and NOS3 gene (NM_000603.5: exon 20: c.2435C > A). There is no report of the coexistence of these two genes. The clinical diagnosis is behavioral variant frontotemporal dementia(bvFTD). The conclusion is that the mutations in MATR3 and NOS3 are likely to be associated with the pathological process of frontotemporal dementia by altering the structure and function of the encoded proteins. The identification of these variations provides new candidate gene combinations for the genetic variation spectrum of frontotemporal dementia, which should be regarded as hypothetical generative observation results. The clinical significance of these results needs to be further verified.