Since aberrant WNT and proliferative activities not only cause congenital defects, but also degenerative diseases and cancers (Nusse and Clevers, 2017), we tested whether the function of LRP4 as a modulator of WNT pathway activation and consequently of Cyclin D1 levels is restricted to the murine forebrain or context-independent. Here, CCND1 is linked to neurodegenerative disease.