As shown in the previous studies (Slaats et al., 2015; Liu et al., 2018), expression of two ion transport proteins, Pkd2 (Polycystic kidney disease 2, TPM: 20.6) and Clcn4 (H+/Cl– exchange transporter 4, TPM: 9.5), were found in the current transcriptome (Table 2). Here, SLC22A23 is linked to polycystic kidney disease.