After working for a while as a peddler, Abraham made enough money to open his own general store. He learned English quickly and even perfected a rural Wisconsin accent, which helped him relate to his customers. Celia, a homemaker, maintained her thick Yiddish accent.
A childhood accident involving a mill at Celia’s family farm had mutilated her left hand, leaving all but her thumb and forefinger useless. “Sometime around age 5,” Dr. Rosenberg wrote in his memoir, “while holding her left hand in both of mine, I told her that I intended to be a doctor so I could repair her hand.”
Leon was an exemplary student: He was valedictorian of his high school and finished summa cum laude at the University of Wisconsin, where he graduated in 1954 and received his medical degree in 1957. He interned at NewYork-Presbyterian Hospital before moving to the National Institutes of Health as a research fellow in 1959.
His first marriage, to Elaine Lewis, ended in divorce. Along with his wife, he is survived by his brother, Irwin, the former dean of the School of Nutrition Science and Policy at Tufts University; his sons, Robert Rosenberg and David Korish; his daughters, Diana Clark and Alexa Rosenberg; six grandchildren; and one great-grandchild.
It was while at Yale that Dr. Rosenberg led research into inherited metabolic disorders, despite skepticism from colleagues about the very basis of such work. “Don’t be silly,” he recalled one Yale nephrologist telling him. “There is no such thing.”
Dr. Rosenberg proved him wrong. He filled lectures with case studies of children — Steven, of course, followed by Dana, Lorraine, Robby and others — who presented inexplicable disorders, which he repeatedly showed to be caused by their bodies’ ability to metabolize various acids, and which could often be easily treated.