Among the protocadherin genes are the previously mentioned PCDHGA1, but also PCDHGA4, of which mutations lead to atrial septal defects [43], PCDHA9 mutations playing a role in valvular defects [73], and altered PCDHGA3 gene expression is strongly associated with reduced stroke volume and ventricular dysfunction [74]. The gene discussed is PCDHGA4; the disease is Abnormal cardiac septum morphology.