Medical mystery: How smoking spared a man from anemia

Scientists discovered that a hemoglobin mutation was causing mild anemia in a young woman in Germany. But why did her father, who has the same mutation, not have anemia, too? The woman, who was in her 20s when diagnosed, and her father share a mutation in the gene that encodes hemoglobin, the protein in red blood cells responsible for taking up and delivering oxygen to cells around the body. The mutation is one of more than 1,000 discovered so far in adult human hemoglobin. Most appear to have..