While DGS/VCFS results from a de novo heterozygous deletion of chromosome 22q11.2 or loss-of-function mutations in the TBX1 coding region,26,27,28,29 an ancestral allele of rs41298798 may replicate some of the effects of TBX1 haploinsufficiency by reducing TBX1 expression. The gene discussed is TBX1; the disease is 22q11.2 deletion syndrome.