Recurrence of extrahepatic biliary atresia in two half sibs.

Extrahepatic biliary atresia (EHBA) usually is a sporadic disorder. Familial cases, including occurrence in sibs and twins, have been reported. We report the first recurrence of EHBA in two half sibs born to a common father and unrelated mothers and suggest the possibility of gonadal mosaicism for a new dominant mutation.