Dup(3)(p2----pter) in two families, including one infant with cyclopia.

We report on 2 unrelated cases of duplication of distal 3p due to balanced maternal translocation t(3;6)(p23;q27) and t(2;3)(p25;p23) respectively. One family was ascertained through the unbalanced offspring and the other through echographic examination of the balanced carrier mother. These cases confirm that dup(3)(p2----pter) results in a characteristic syndrome with distinctive facial appearance. In family 2 inspection of a photograph of a deceased sib was sufficient to conclude that he was affected. The patient in family 2 had cyclopia. Since holoprosencephaly was also reported by Martin and Steinberg [1983], we conclude that this anomaly appears to be a sign of the syndrome. The duplication usually derives from a maternal balanced translocation, in most cases from adjacent-1 segregation. However, family 2 was ascertained through a balanced female carrier who inherited the translocation from the father. We have noted that the second chromosome (which varies without apparent preferences) involved in these translocations is broken consistently at a distal band.