The Errant Heart

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Science  07 Jul 2006:
Vol. 313, Issue 5783, pp. 20
DOI: 10.1126/science.313.5783.20a

Atrial fibrillation (AF) is a common and life-threatening condition in which erratic electrical activation of muscle cells in the upper chambers of the heart causes inefficient pumping of blood. As a result, blood pools in the heart and can form clots, which in turn increases the risk of stroke. Although AF typically arises in the context of other heart conditions, some patients present with AF on its own, and these individuals may provide valuable insights into the genetic determinants of the disorder.

Studying heart tissue from 15 patients who developed idiopathic AF at an early age (their hearts were otherwise normal), Gollob et al. found that four patients carried missense mutations in the gene encoding connexin 40. Connexins are protein components of gap junctions, channels that conduct current between neighboring cells. Notably, in three patients, the mutations were not present in the germ line but instead were confined to heart tissue. Such tissue-restricted somatic mutations are a common cause of cancer, but this genetic mechanism is almost unprecedented in other human diseases. — PAK

N. Engl. J. Med. 354, 2677 (2006).

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