A 5;7, 5;12 double reciprocal translocation in a normal mother and a 5;7 translocation with a recombinant chromosome 5 in her normal child.

A phenotypically normal mother had two apparently balanced translocations involving chromosomes 5, 7, and 12. Her karyotype was 46,XX,t(5;7) (5;12) (p14q34;p14;q21), while her daughter, who was also phenotypically normal, had inherited only one of the translocations. Her karyotype was 46,XX,-5,-7,+rec(5)t(5;7) (q34;p14)mat,+der(7)t(5;7) (q34;p14)mat. The other was lost during a meiotic crossing over, giving the daughter an apparently balanced chromosome complement.