For this reason, fluorescent in situ hybridization was performed using DNA fluorescent probes for the DiGeorge/velocardiofacial syndrome critical region (TUPLE1) at 22q11.2 and a control probe, arylsulfatase-A (ARSA), at 22q13.3, from a commercially available source (Vysis). Here, ARSA is linked to 22q11.2 deletion syndrome.