Thus, mutations in MXEs have been shown to cause diseases such as Timothy syndrome (missense mutation in the CACNA1C gene) (Splawski et al, 2004, 2005), cardiomyopathy (defect of the mitochondrial phosphate carrier SLC25A3) (Mayr et al, 2011) or cancer (mutations in, e.g., the pyruvate kinase PKM and the zinc transporter SLC39A14) (David et al, 2010). Here, CACNA1C is linked to cancer.