PPP1R12A and atrial conduction disease: Importantly, these CCDD phenotypes can be connected to the maldevelopment of their disease-relevant cMNs: CFEOM to cMN3/4, CP to the superior branch of cMN3, FNP to cMN4, DRS to cMN6, CFP to cMN7, and MBS to cMNs 6 and 7 (Fig. 1a and Supplementary Table 1).