TBX1 is known to be responsible for several of the major 22q11 deletion syndrome phenotypes, including abnormal facies (conotruncal anomaly face), cardiac defects, thymic hypoplasia, velopharyngeal insufficiency with cleft palate and parathyroid dysfunction with hypocalcaemia.43 This stop-gain removes the last 19 amino acids of exon 9A of a minor isoform of the gene.44 Though TBX1 as a whole is considered essential for life, this variant proves that at least the last 19 amino acids of this isoform are not. Here, TBX1 is linked to Hypocalcemia.