Abstract
Sudden infant death syndrome is defined as sudden and unexpected death of an infant that remains unexplained after thorough investigation of the scene of death, medical history and autopsy. Although a common final pathogenic pathway of these deaths is assumed, even recent studies based on next generation sequencing failed to reveal a single genetic cause.
Predominant role of a pathogenic variant in one of the candidate genes may be traced in approximately 10% of these infants. The candidate genes include genes encoding ion channels in the heart that lead to inherited primary arrhythmia syndromes (cardiac channelopathies), for example long QT syndrome and catecholaminergic polymorphic ventricular tachycardia.
Their inheritance is mostly autosomal dominant with an increased risk of the disease associated with sudden death for first-degree relatives. Therefore a thorough cardiological examination of first-degree relatives and post-mortem molecular testing of the cardiac channelopathies are recommended.
Other candidate genes include genes for sodium channels in the respiratory skeletal muscles and brain or genes encoding mineralocorticoid receptor or enzymes involved in adrenal steroidogenesis. Results of post-mortem genetic testing, especially in cases of sudden infant death syndrome, must be interpreted with caution.
Only strictly assessed pathogenic variants may be used for genetic counseling in the family, always in correlation with clinical findings.