By Laura Beil
The patient, known as only “MBM,” was just 7 years old the first time doctors saw her. She had always been prone to night sweats, but now excessive perspiration was forcing her to change clothes several times a day. She was endlessly thirsty, fatigued and losing weight despite a voracious appetite. A dozen years later, at age 19, doctors checked her into a hospital, thinking she had some kind of unusual metabolic condition. After aggressive treatment with drugs, her symptoms improved, but only for a short time, and the next year surgeons removed most of her thyroid. When she was 35 — gaunt, weak and losing hair — doctors began searching every tissue of her body for a diagnosis.
They finally located the problem. It was MBM’s mitochondria, the organelles that supply the energy for cells to function. Thanks to mitochondria, the sandwich you had for lunch is now powering your heart and brain. Somehow the mitochondria inside MBM’s cells had gone haywire, becoming too large and too numerous. Such damage was “the first instance of a spontaneous functional defect of the mitochondrial enzyme organization.” The mysterious case of patient MBM was considered so remarkable that the Journal of Clinical Investigation published a description of it. That was in 1962.