Balanced reciprocal translocation mosaicism associated with an abnormal phenotype.

Balanced reciprocal translocation mosaicism is rarely reported in humans. Only two previous cases have been associated with an abnormal phenotype. We report on a third case of apparently balanced reciprocal translocation mosaicism associated with an abnormal phenotype, largely different from those reported previously. Since low levels of mosaicism may not be detected in routine cytogenetic analyses, balanced reciprocal translocation mosaicism may be associated with an abnormal phenotype more often than has been recognized to date.