[Atresia of the esophagus. Study of a cluster observed in 1984 in the Rhône-Alpes region].

The Rhône-Alpes Auvergne Register allows the monitoring of malformations, in 2 French regions. This monitoring led to the discovery of a cluster of cases of esophageal atresia of the isolated type during the year 1984. Analysis of this cluster showed that it was mainly due to a concentration of cases (7 observed vs 1.78 expected) born in the Ain department, 4 of them being born during the first trimester. Analysis of the cluster was followed by an individual questioning of families. It concerned essentially the environmental conditions of the onset of pregnancy and did not allow to set the hypothesis of a possible risk factor. The authors conclude that either the cluster should be attributed to chance, or the used questionnaire, even if directed towards all directions and seeming quite complete, was not sufficient to allow bringing out an hypothesis.