Novel NALCN variant: altered respiratory and circadian rhythm, anesthetic sensitivity.

The sodium leak channel, a Na+-permeable, nonselective cation channel, is widely expressed in the nervous system, contributing a basal Na+-leak conductance and regulating neuronal excitability. A 3-year-old girl, heterozygous for a de novo missense mutation in NALCN (c.956C>T; p.Ala319Val) predicted to be deleterious, presented from birth with: stimulus-induced, episodic contractures of the limbs and face with associated respiratory distress; distal arthrogryposis; severe axial hypotonia; and severe global developmental delay (CLIFAHDD syndrome). In infancy, she manifested a reversed sleep-wake rhythm, nocturnal life-threatening respiratory rhythm disturbances with central apnea. Sevoflurane sensitivity caused respiratory depression and cardiac arrest.