C3 and early-onset autosomal dominant Alzheimer disease: Under pathological conditions such as those associated with traumatic brain injury, multiple sclerosis, and Alzheimer’s disease (AD), complement proteins, including C3, are linked to impaired cognitive functions (Carpanini et al., 2019; Schartz and Tenner, 2020; Bourel et al., 2021; Saez-Calveras et al., 2022).