Fig. 1: Findings in patients with reciprocal balanced translocations (RBTs).

(a) Possible chromosomal complements in gametes of patients with balanced translocations. At meiosis I, translocated chromosomes and their normal homologues synapse to form a quadrivalent. Balanced gametes containing either the normal nonhomologous chromosomes or both translocated chromosomes produced by alternate segregation are specified by green borders. Unbalanced gametes are specified by red borders. Modes of chromosome segregation from a quadrivalent are shown: 2:2 (two nonhomologous or two homologous chromosomes segregate together in adjacent-1 or adjacent-2 disjunction, respectively), 3:1 (three chromosomes segregate to one cell and one to the other), and 4:0 (all chromosomes segregate together). ^†Nondisjunction of the sister chromatids during meiosis II may result in occurrence of gametes with additional chromosome abnormalities. (b) Pie chart showing reproductive outcomes. (c) The rate of aneuploid conceptions in male and female patients. Asterisks indicate statistically significant sex bias. No difference in male and female patients was observed for 3:1 segregation mode.