The t(8;22) is part of a complex rearrangement involving an inversion of the 22q11.2 region. (A) Schematic of the location of cosmid probes used in FISH experiments relative to low copy repeats (LCRs A to E, shaded boxes) within 22q11.2. Interpreted structures of the der(8) and der(22) chromosomes are shown below the normal chromosome 22 structure. (Hatched ovals) centromeres; (CECR), cat eye syndrome minimal chromosomal region. (B–D). Dual-color FISH was performed on metaphase chromosomes from lymphoblast cells derived from the balanced t(8;22) carrier (father of the supernumerary t(8;22) der(22) proband). Differentially labeled cosmid probes were applied in the following combinations: (B) 68a1 (a.k.a. N41) (red), 87f9 (a.k.a. ZNF74) (green), and control probe Cos82 (red); (C) 103a2 (red), 45c9 (green), and Cos82 (red); (D) 56d3 (red), and a distal control probe, Cos82, (green).
