(A) Schematic of chromosome 22 demonstrating critical DiGeorge syndrome (DGS) region, site of commercially available FISH probes and genes encoded with DGS region.
(B) FISH analysis of metaphase spread using commercially available chromosome 22q11.2 probe (green areas, dashed arrows) and control chromosome 22 probe outside of critical DGS region (red areas, arrowheads). (B1) Patient with chromosome 22q11.2 deletion as demonstrated by binding of 22q11.2 probe to only one chromosome. (B2) Normal control with binding of probe to both copies of chromosome 22.