Her baby died in his sleep. Her 29-year quest to find out why has led to a big breakthrough on SIDS

To new parents, many things are terrifying—yet few of them are as scary as Sudden Infant Death Syndrome, or SIDS. Much of how and why SIDS occurs is still unknown, but a new piece of research, published last week in eBioMedicine, found clues suggesting that there might be a biological component to it. Compared to other babies, both living and who died of other causes, infants who died of SIDS were consistently found to have lower levels of butyrylcholinesterase, an enzyme that helps provide arousal from sleep.