TBX1 and 22q11.2 deletion syndrome: First, the results suggest a resolution to a discrepancy in the literature between previous studies reporting normal hearing in the Df1/+ and Df(16)A/+ mouse models of 22q11DS [23-25] and studies documenting a high incidence of middle ear disease in mice heterozygous for the gene Tbx1 [26], which is included in the Df1/+ and Df(16)A/+ deletion regions.