Extrahepatic biliary atresia in twins: zygosity determination by short tandem repeat loci.

Extrahepatic biliary atresia (EHBA) is an infantile obstructive cholangiopathy of unknown etiology. This condition is generally thought to be an acquired disease without familial tendency. We reported eight pairs of discordant twins in a series of 143 patients with operatively established EHBA, One pair was dizygotic twin from sex discrimination. Six were identical ABO blood groups and 2 were also the same minor blood groups (Dce, MM and Le a-b-). The last 2 sets were monzygotic twins by common DNA polymorphisms short tandem repeat loci. Our findings support the hypothesis that, EHBA is an acquired rather than a hereditary disease.