KCNQ genes encode potassium channels that have been associated with both cardiac and hearing abnormalities in humans, most notably the KNCQ1 gene. Using a partial KCNQ3 cDNA Kubisch et al. screened a human retinal cDNA lambda phage library and obtained a novel homolog they named KCNQ4. When expressed in Xenopus oocytes KCNQ4 encodes a potassium current inhibited by 30% in the presence of 200 μM linopridine, whereas the current due to KCNQ3/KCNQ4 heteromers in the same study was inhibited by 75% at that concentration. Kubisch et al. also mapped the KCNQ4 gene to the 1p34 human chromosome, in a region associated with autosomal dominant deafness DFNA2A. Subsequent studies have identified additional families with mutations in KCNQ4 and hearing loss. KCNQ4-specific openers could possibly treat progressive hearing loss and tinnitus Kubisch et al..