Since we have identified disease‐causing mutations other than DRC1 in 18 families in this group (Kano et al., 2016; Orimo et al., 2019; Takeuchi et al., 2018; Tanaka et al., 2012), DRC1 acts as a disease‐causing gene in 49% of these Japanese PCD patients, followed by DNAH5 (31%) and DNAH11 (12%) (Table 2). Here, DRC1 is linked to primary ciliary dyskinesia.