My son had genetic testing when he was 2. i just read about 22q11.2 deletion syndrome. would that be detected from standard genetic testing?

Yes: The 22q11.2 deletion syndrome is diagnosed in individuals with a submicroscopic deletion of chromosome 22 detected by fluorescence in situ hybridization (FISH.), See link for more details

It would now, from a: Chromosomal Microarray, molecular genetic testing that is standard of practice for geneticists & developmental pediatricians for infants & children with developmental delays &/or Autistic Spectrum Disorder. A standard karyotype would not have identified a small sequence of deleted genes at 22q.11.2., only a FISH test of Chromosome 22 in the VCF region., done if there was clinical suspicion.