GATA3 haploinsufficiency at 10p14 causes hypoparathyroidism with renal/otic anomalies and generally spares T-cell development, because GATA3 expression in early T-cell progenitors is regulated by a monoallelic-to-biallelic transcriptional switch that compensates for the loss of one allele and maintains sufficient protein levels for normal T-cell maturation [53,54,55,56]. This evidence concerns the gene GATA3 and hypoparathyroidism.