The hearing threshold of 4-month-old adult Nptn−/− mice (n = 3, 90 dB) was significantly higher than in wild-type littermate controls (n = 3, 30–40 dB; p < 0.0001) (Fig. 1A) and revealed deafness in Nptn−/− mice similar as reported for the previously characterized neuroplastin mutants (Carrott et al. 2016; Zeng et al. 2016). The gene discussed is NPTN; the disease is deafness.