TBX1 and 22q11.2 deletion syndrome: In contrast, we have reported partially penetrant palatal closure defects (16) and cranial skeletal anomalies (17) in the LgDel mouse model of 22q11DS, which carries a heterozygous deletion orthologous to the minimal critical deletion associated with 22q11DS in humans, resulting in diminished dosage of Tbx1 and 27 other murine 22q11 orthologues (15).