Did a celebrated researcher obscure a baby's poisoning?

Summary

Opioids kill by suppressing the drive to breathe. They bind to receptors in the brain stem, altering the neurons that maintain patterns of respiration. Carbon dioxide builds up in the bloodstream, hypoxia sets in, and circulation falters. Brain damage follows, then death.The coroner’s office asked one of Canada’s leading pediatricians and toxicologists, Gideon (Gidi) Koren, to examine Tariq’s file. For the past two decades, Koren had been running a program at the Hospital for Sick Children called Motherisk, which provided guidance for pregnant women and new mothers about drugs and breast-feeding. He was widely considered to be among the most capable research scientists in the field. Koren met with Rani’s physician and quickly ruled out foul play. “There was no evidence of psychiatric issues,” he later wrote. Instead, Koren interpreted the toxicology report as a scientific revelation: if mothers with a certain genetic predisposition took even a mild dose of codeine, the amount of morphine that ended up in their breast milk could kill their children.A dose of codeine brings relief from pain only when the liver metabolizes a fraction of it into morphine. But the exact proportion that is converted into morphine can vary. Most people have two copies of the gene that carries out the conversion. Koren invited Rani to be tested, and discovered that she had three.The concentration of morphine in Tariq’s blood was measured at seventy nanograms per millilitre. “If you have levels above twenty, you stop breathing,” Koren later said. Six months after Tariq’s death, Koren obtained a sample of Rani’s breast milk, which she had kept in her freezer. His lab measured its morphine concentration at eighty-seven nanograms per millilitre. Koren was stunned. “The level was several fold higher than ever described in the literature,” he noted. “This was the first time in history that a baby was reported dying from breast milk.”Koren had long studied the transmission of opioids into breast m...