Mutant Gene Shatters Nerves: Was Abe Lincoln Affected?

... If you bend a knee or an elbow, the nerves in your limbs stretch but do not break. A University of Utah study suggests why: A gene produces a springy protein that keeps nerve cells flexible. When the gene was disabled in tiny nematode worms, their nerve cells literally broke. The discovery may provide a new explanation for spinocerebellar ataxia type 5 (SCA5) -- a disease previously tied to a human version of the gene and identified in 11 generations of U.S. President Abraham Lincoln's family, starting with his paternal grandparents. SCA5 may have afflicted Lincoln himself. The new study suggests how. ...