biostudies-literatureUnknown30(7)Tadros RCanada Research Chairs ProgramCanadian Institutes of Health ResearchThe investigation of sudden death is challenging, but of utmost importance to guide screening in potentially at-risk relatives. We present a case of a 14-year-old boy of Central Asian ancestry with palpitations and recent sudden death of his sister. Autopsy revealed ischemic injury of uncertain etiology. Family evaluation revealed mild QT prolongation in relatives cosegregating with a novel CACNA1C variant (Gly856Asp). Functional in vitro analyses show slower inactivation kinetics (gain of function) as shown in the long QT syndrome type 8. The case highlights the importance of a holistic approach to the investigation of sudden death and screening of at-risk relatives.JACC. Case reports103503https://www.ebi.ac.uk/biostudies/studies/S-EPMC12046830biostudies-literatureA Novel Gain-of-Function CACNA1C Variant (Gly856Asp) Associated With QT Prolongation and Sudden Death.PMC12046830Fournier AParent LLeduc CBouron-Dal Soglio DZhao JTadros RfalseA Novel Gain-of-Function CACNA1C Variant (Gly856Asp) Associated With QT Prolongation and Sudden Death.The investigation of sudden death is challenging, but of utmost importance to guide screening in potentially at-risk relatives. We present a case of a 14-year-old boy of Central Asian ancestry with palpitations and recent sudden death of his sister. Autopsy revealed ischemic injury of uncertain etiology. Family evaluation revealed mild QT prolongation in relatives cosegregating with a novel CACNA1C variant (Gly856Asp). Functional in vitro analyses show slower inactivation kinetics (gain of function) as shown in the long QT syndrome type 8. The case highlights the importance of a holistic approach to the investigation of sudden death and screening of at-risk relatives.2025-01-01T00:00:00Z2025 Apr2025-07-08T03:11:31.502Z2025-07-08T03:11:31.502ZS-EPMC120468304018557510.1016/j.jaccas.2025.103503