KCNJ16 associated Hypokalaemic Tubulopathy and Deafness presenting with Sudden Cardiac Arrest.

Abstract Inwardly rectifying potassium channels (K ir ) allow potassium (K+) to easily move into cells. They are implicated in several diverse physiological processes throughout the body. KCNJ16 associated tubulopathy and deafness affects a subset of K ir transport channels. This disease was first described in 2021, amongst a cohort of 9 patients in total. Sudden cardiac arrest has been described as a presenting symptom of tubulopathy previously. We report the case of an infant who presented with sudden cardiac arrest (SCA) aged 7 months secondary to severe hypokalaemia. Singleton exome analysis identified apparent homozygous missense variants in KCNJ16 (c.409C>G; p.R137G). To our knowledge, this is the first description of sudden cardiac arrest at presentation in this form of tubulopathy.