DIAPH1 and deafness: [3] 1997 marked the identification of DIAPH1 as the initial causative gene of autosomal dominant non-syndromic hearing loss (ADNSHL) in a sizable Costa Rican relative who presented with profound, bilateral deafness encompassing all frequencies by the time they were 30 years old, whereas low-frequency deafness commenced around the age of ten.