A mirror image of the first and second branchial arch syndrome associated with cleft lip and palate in monozygotic twins.

A rare case of monozygotic twins revealing a mirror image of the first and second branchial arch syndrome with accessory ear and hemifacial microsomia, associated with unilateral cleft lip and palate, is presented. Although the concordance and/or discordance rate of monozygotic or dizygotic twins with cleft lip and palate is well reported, that of twinning of the first and second branchial arch syndrome has been very rarely described. First and second branchial arch syndrome occurs sporadically but cleft lip and palate are strongly related to the influence of environmental factors with a considerable hereditary tendency. The study of twinning of congenital anomalies is important in the investigation of the pathogenesis of genetic and environmental effects. The twins were diagnosed as monozygotic with almost complete certainty by ABO blood typing, HLA typing, finger prints, and DNA typing. Concordance was noticed, which suggests a hereditary tendency. Since concordance in these monozygotic twins was exhibited by a precise mirror image of first and second branchial arch syndrome, spinal scoliosis and cleft lip and palate, it is possible that an environmental factor induced these complex anomalies.