IDENTICAL CHROMOSOME IMBALANCE IN 2 SIBLINGS BORN TO A MOTHER WITH A DOUBLE RECIPROCAL TRANSLOCATION

We report the case of a woman who carried two reciprocal translocation s. Her karyotype was 46,XX,t(3;12)(q12;q21)(4;17)(p14;p13). She had tw o children, a phenotypically normal daughter (karyotype (46,XX,t(3;12) (q12;q21)) and a son with partial 4p trisomy (karyotype 46,XY,t(3;12) (q12;q21),-17,+ maternal der(17)). She was pregnant with a female fetu s who had the same karyotype as her son. She also reported a history o f two spontaneous abortions. This viable recurrent abnormality was due to the maternal (4;17) translocation with meiotic segregation type 2: 2 adjacent 1. In this case of the two reciprocal translocations carrie d by the mother, one led to imbalances. whereas the other remained bal anced in the viable offspring.