Genetic counselling in cases of anal and rectal atresia.

The familial occurrence of anal and rectal atresia is investigated in literature including a material of 169 patients of children's hospitals in Munich. Positive family history was found for only one of 169 patients. The mode of inheritance in those families with more than one affected member is generally considered to be autosomal recessive, although several families with X-chromosomal recessive inheritance have been described. In approximately 50% of the cases, anal atresia is associated with other malformations. Twin studies indicate that genetic factors play only a minor role in the etiology. The genetic risk in cases of isolated anorectal atresia is estimated to be well below 1%.