CUBN and Gerstmann syndrome: Many studies have addressed the clinical relevance of mutations in human CUBAM, and recently it has been shown that individuals with Imerslund-Gräsbeck syndrome (I-GS), who have CUBN mutations that affect the C-terminal half of the protein, exhibit isolated proteinuria that has been interpreted as being due to defects restricted to albumin reabsorption by proximal tubular cells (Bedin et al., 2020).