Even if mitochondrial dysfunction may account at least for some of the neurodegenerative features observed in CS patients, some cytological abnormalities found in the brains of CS patients, such as the appearance of binucleated neurons and multinucleated astrocytes (Itoh et al., 1999; Weidenheim et al., 2009), appear to arise from a defect in cell division due to the lack of CSA or CSB, which have recently been shown to exert a role in the last step of cytokinesis, the abscission (Paccosi et al., 2020). This evidence concerns the gene ERCC6 and Cowden syndrome 1.