Given that Willin/FRMD6 is highly expressed in brain endothelial cells [43] and in the choroid plexus ([42], http:/www.proteinatlas.org, accessed on 1 August 2021), we briefly discuss potential mechanisms through which Willin/FRMD6 dysfunction may be involved in BBB dysfunction relevant to AD. This evidence concerns the gene FRMD6 and Alzheimer disease.