Connexin43 Mutations in Sporadic and Familial Defects of Laterality

To the Editor: Britz-Cunningham et al. (May 18 issue) 1 describe missense base substitutions in the connexin43 gene in all six patients with heterotaxia they studied. Heterotaxia is a syndrome of multiple malformations in which the developing embryo fails to establish normal left–right asymmetry. Four of the six patients carried two different base changes, and one base change, Ser364Pro, was identified in five. The results suggest that connexin43 mutations account for a large percentage of the cases of heterotaxia, that most such cases are likely to be recessive, and that one base substitution, Ser364Pro, may account for a considerable percentage of . . .