Although substitution of R163 with alanine did not alter its ability to inhibit ClC-3, we identified a mutation of the gene encoding T9A that was observed in a person with lung cancer (National Cancer Institute Genomic Data Commons data portal), in which R163 is replaced with leucine, weakening the inhibitory effects of T9A on ClC-3 (Extended Data Fig. 8f). Here, CLCN3 is linked to lung carcinoma.