Diagnosis defined
Today: Misha Angrist, a senior fellow at the Initiative for Science & Society and associate professor of the practice at the Social Science Research Institute at Duke University (the views he expresses here are his alone).
Issue No. 440
To Name a Rare Disease
Misha Angrist
HYDRANYM No. 24
The Editors
To Name a Rare Disease
by Misha Angrist
In 2022, a baby formula plant in Sturgis, Michigan, owned by Abbott Laboratories, was closed down after the FDA cited it for unsanitary practices. In addition to halting the supply chain of standard baby formula, the plant’s closure interrupted deliveries of medical foods, including products that people with rare metabolic diseases need in order to survive.
Karen Dolins, a registered dietician and nutritionist who teaches at Columbia, has an adult daughter who has one of these conditions—the one known as maple syrup urine disease. Patients with this genetic disorder are unable to break down protein. While fielding media queries about the acute shortage, Dolins tried to explain that what was happening at Abbott was a grave threat to vulnerable adult patients with diseases like MSUD.
“One journalist actually said to me, ‘Maple syrup urine disease? Well, that doesn't sound too serious,’” she told me. “And I thought, ‘Oh my God, we really need a name change.’”
For the last several years I have been working on a book about maple syrup urine disease, which was first described in 1954 by pediatrician John Menkes. While interning at Boston Children’s Hospital, he’d seen a sick infant whose parents had had three prior babies die in infancy. The mother had noticed an unusual odor in those babies, but not in their lone healthy sibling. By day three Menkes’s patient developed the same sweet smell in his urine, sweat, and earwax. Baby “James J. H.” would die at two weeks of age.
In the early 1960s doctors at Bellevue Hospital proved that babies with MSUD could survive on a diet of specialized formula. We already knew by then that for people with another congenital metabolic disorder, phenylketonuria (PKU), a diet free from the amino acid phenylalanine would keep affected kids fairly healthy. For MSUD patients, the offenders are the three so-called branched-chain amino acids: leucine, valine, and isoleucine.
MSUD is caused by a broken gene that prevents patients from metabolizing these protein building blocks; the maple syrup smell derives from a compound called sotolone, a metabolite of isoleucine that is indeed present in maple syrup. High quantities of leucine and its derivatives are particularly toxic to the brains of these patients. If babies with classic MSUD consume protein (e.g., human breast milk, any kind of meat), their brains swell, and they experience seizures; left untreated, they will die within a few weeks or months.
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