Patients with deletion in NKCC1 suffer from multiorgan failure [60] or global developmental delay, together with hearing loss, gastrointestinal abnormalities, and absent salivation (named Kilquist syndrome [59]), while a gain-of-function missense variant of NKCC1 has been linked to schizophrenia [62]. Here, SLC12A2 is linked to Kilquist syndrome.