The sodium leak channel non-selective protein NALCN, a nonselective cation channel, forms the background Na+ leak conductance and controls neuronal excitability (Lu et al. 2007, Ren 2011). Mice with mutant NALCN have a severely disrupted respiratory rhythm and die within 24 hours of birth. Calcium (Ca2+) influences neuronal excitability via the NALCN:UNC79:UNC80 complex, with high Ca2+ concentrations inhibiting transport of Na+ (Lu et al. 2010). Mutations in human NALCN lead to complex neurodevelopmental syndromes, including infantile hypotonia with psychomotor retardation and characteristic facies (IHPRF) and congenital contractures of limbs and face, hypotonia and developmental delay (CLIFAHDD) (Bouasse et al. 2019).