TBX1 and benign neoplasm of parathyroid gland: Notably, their expression is aberrant in parathyroid tumors: HOX genes are deregulated in parathyroid benign tumors [2], activating variants of the glial cell missing 2 (GCM2) gene have been identified in familial and sporadic cases of PHPT [3,4,5], and the T-box transcription factor 1 (TBX1) gene is downregulated in parathyroid tumors [6,7].