The Lessons of Progeria
Could a rare genetic disease that “ages” children help explain the adult aging process?
Just as the gene responsible for Tangier disease revealed how high-density lipids (HDL) work, an even rarer single-gene disease called progeria, which causes extremely premature aging in children, could illuminate the aging process in healthy adults. With progeria, which affects perhaps 50 children worldwide, the guilty mutation arises in the father’s sperm in a gene called lamin A, which normally helps build part of the membrane scaffolding for the cell’s nucleus. The mutation produces a malformed protein, progerin, causing cell damage that effectively ages skin, bones and hair, as well as the arteries. People with progeria usually die from the ravages of arteriosclerosis by age 13.
Studies of recently developed mouse models of progeria have shown that an experimental cancer drug called a farnesyltransferase inhibitor (FTI) can reverse this arterial damage. Children’s Hospital Boston is now conducting two clinical trials to discover if FTIs have the same effect in human progeria patients; the hospital has recruited 28 subjects.
Whether the aging seen in progeria patients actually relates to typical aging is open to debate, but in 2007, researchers from the National Human Genome Research Institute and the National Heart, Lung and Blood Institute discovered trace amounts of progerin in the skin cells of the elderly; when the scientists allowed these cells to age further in the laboratory, progerin levels increased. A year later, a group at Stockholm’s Karolinska Institute found that turning off the abnormal progerin gene reversed abnormalities in the skin and teeth of mice with progeria. Now researchers are keen to confirm whether the protein’s accumulating toxic effect on our cells’ nuclear membranes actually contributes to our withering in old age.