The familial occurrence of duodenal atresia is uncommon. This study evaluated 
the inheritance patterns, the nature and associations, and the presence of 
immunologic deficits in duodenal atresia recurring in at least three siblings 
each in two nonrelated families. In the first family, an association with 
Fanconi's anemia was observed in three of seven pregnancies (2 boys, 1 girl) 
suggesting an autosomal recessive mode of transmission. Patients died as a 
result of overwhelming (fungal) septicemia in association with pancytopenia. In 
a second family, identical multiple atresias occurred in two female siblings 
born 18 months apart and a third child with a duodenal stenosis. Overwhelming 
sepsis and a T-cell dysfunction was seen in the postoperative period, which had 
partially corrected by follow-up at 5 months. A history of family occurrence of 
duodenal atresia should alert the physician to the possibility of associated 
pathology including immune deficiency states.