Impairment of the BBB in patients with AD is now a well-recognized pathology (Saraiva et al., 2016; Zlokovic, 2011; Chen et al., 2021), and previous disagreement about the involvement of the BBB in AD pathology may be due to the use of different assays, such as: the ratio of albumin in cerebrospinal fluid (CSF) and plasma (QAlb), soluble platelet-derived growth factor receptor β (sPDGFRβ), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), and the use of a variety of other methods (Preis et al., 2024). The gene discussed is ALB; the disease is Alzheimer disease.