Mitochondrial DNA in Aging and Disease; August 1997; Scientific American Magazine; by Wallace; 8 Page(s)
At age five a seemingly healthy boy inexplicably began to lose his hearing, which disappeared entirely before he turned 18. In the interim, he was diagnosed as hyperactive and suffered occasional seizures. By the time he was 23, his vision had declined; he had cataracts, glaucoma and progressive deterioration of the retina. Within five years he had experienced severe seizures, and his kidneys had failed. He died at 28 from his kidney disorder and a systemic infection.
At the root of his problems was a minute imperfection in his genes--but not in the familiar ones residing in the long, linear strings of chromosomal DNA that populate every cell nucleus. Instead he was killed by an abnormality in tiny circles of lesser known DNA located in his mitochondria, the power plants of cells. Each such circle contains the genetic blueprints for 37 of the molecules mitochondria need to generate energy.