To date, more than 100 GJB2 variants have been reported (see the Connexin‐deafness homepage: http://davinci.crg.es/deafness/), and there has been a general rule applied to the relationship between mutations and hearing loss; that inactivating mutations (deletion mutations and stop mutations) result in more severe phenotypes compared to those caused by non‐inactivating mutations (missense mutations) (Tsukada et al., 2010). The gene discussed is GJB2; the disease is hearing loss disorder.