TBX1 and 22q11.2 deletion syndrome: Only 9 patients with VCFS have been identified to have TBX1 mutations [33]–[35], while a large number of patients were determined to be negative for TBX1 mutations [36], [37], and it seems that this disease was not caused by a single gene mutation or dosage alteration, but resulted from a combined effect of many genes [38].