Abstract TANGO2 deficiency disorder (TDD) is a rare, autosomal recessive condition caused by pathogenic variants in TANGO2 , a gene residing within the region commonly deleted in 22q11.2 deletion syndrome (22q11.2DS). Although patients with 22q11.2DS are at substantially higher risk for comorbid TDD, it remains underdiagnosed within 22q11.2DS, likely due to overlapping symptomatology and a lack of knowledge about TDD. Initiation of B‐vitamin supplementation may provide therapeutic benefit in TDD, highlighting the need for effective screening methods to improve diagnosis rates in this at‐risk group. In this retrospective, multicenter study, we evaluated two cohorts of patients with 22q11.2DS (total N = 435) for possible comorbid TDD using two different symptom‐based screening methods (free text‐mining and manual chart review versus manual chart review alone). The methodology of the cohort 1 screening method successfully identified a known 22q11.2DS patient with TDD. Combined, these two cohorts identified 21 living patients meeting the consensus recommendation for TANGO2 testing for suspected comorbid TDD. Of the nine patients undergoing TANGO2 sequencing with del/dup analysis, none were ultimately diagnosed with TDD. Of the 12 deaths in the suspected comorbid TDD cohort, some of these patients exhibited symptoms (rhabdomyolysis, cardiac arrhythmia, or metabolic crisis) suspicious of comorbid TDD contributing to their death. Collectively, these findings highlight the need for robust prospective screening tools for diagnosing comorbid TDD in patients with 22q11.2DS.

Multicenter appraisal of comorbid TANGO2 deficiency disorder in patients with 22q11.2 deletion syndrome