Sudden unexplained death in childhood (SUDC), similar to sudden infant death syndrome (SIDS), occurs when children between the ages of 1 year old and 18 years old die without any obvious explanation, usually in their sleep. SUDC, however, is less common than SIDS, and unlike SIDS, hasn't been examined at a genetic level – until recently.
Thanks to the founder of the non-profit SUDC Foundation, Laura Gould, who lost her own daughter to SUDC, and neurologist Orrin Devinsky of NYU Langone Health, there's a registry of SUDC cases that researchers have used to sequence DNA from children with SUDC to look for genetic clues behind their deaths.
In these recent genetic analyses, mutations linked to epilepsy, cardiac arrhythmias and neurodevelopmental disorders were suspected to have contributed to SUDC in at least a small portion of the cases.
One study published in Proceedings of the National Academy of Sciences in December of last year looked at 124 families with children between the ages of 11 months and 19 years who had died a sudden unexplained death. These researchers looked at both parents' and their child's DNA and found variants in 8 genes that they think contributed to 11 of the deaths. In 7 of the 11 deaths, these mutations were found only in the child, not in his or her parents, providing more evidence that these mutations possibly contributed to SUDC. Six of these gene variants were involved in calcium signaling, which helps regulate the heart and nervous system.
Another study in Genetics in Medicine examined 352 cases of SIDS and SUDC to look for mutations in nearly 300 genes linked to neurological conditions, cardiac dysfunction and metabolic and multiple-organ conditions. Possible genetic variants contributing to SUDC were found in genes previously associated with neurodevelopmental disorders and in the SCN1A gene linked to epilepsy.
According to Dr. Devinsky, children who die these sudden, unexplained deaths are 10 times more likely, compared to an average child, to have had a history of seizures while sick with a fever.
Although neither study confirms that specific mutations are responsible for SUDC and that the presence of one of these genetic variants does not mean that a child will die with SUDC, these genetic clues provide reason to further examine these genes in animal studies to better understand how they might interfere with vital body functions. And perhaps from these studies, eventual screening tools can be developed to prevent SUDC or at least know who's at risk for it.