Molecular autopsy implicates primary carnitine deficiency in sudden unexplained death and reversible short QT syndrome

We report a case of sudden unexplained death in a young asymptomatic woman in whom postmortem genetic testing after a negative autopsy identified a homozygous pathogenic mutation in SLC22A5 which leads clinically to primary carnitine deficiency (PCD). Her brother was subsequently diagnosed clinically with short QT syndrome, received an implantable defibrillator, and was then found to carry the same pathogenic homozygous mutation and critically low levels of carnitine. His QT interval improved with the use of carnitine supplementation, highlighting the close relationship between electrophysiology and biochemistry, and the importance of postmortem genetic testing in the clinical management of surviving relatives.