Unbalanced karyotype with normal phenotype in a family with translocation (8;13)(p21;q22)

We describe a family with translocation (8;13) (p21;q22), in which both unbalanced products of adjacent-1 segregation occurred. Two members of the family have partial trisomy 8p with partial monosomy 13q; two others have partial monosomy 8p with partial trisomy 13q. The latter are both phenotypically normal, which is a highly unusual observation. One of these is, in addition, a carrier of a de novo balanced translocation between chromosomes 2 and 19. The risk for unbalanced progeny is discussed.