TBX1 and 22q11.2 deletion syndrome: Microdeletion 15q11.2q12 was associated with Prader-Willi syndrome in 1981 [11], a 17p13.3 deletion was found in Miller-Dieker lissencephaly syndrome [12], a 1.5 to 3.0-Mb hemizygous deletion of chromosome 22q11.2 causing haploinsufficiency of the TBX1 gene was discovered in DiGeorge syndrome [13], whereas the first recurrent microduplication was identified in 1991 in patients with Charcot-Marie-Tooth disease type 1A (CMT1A) [7].