Although haploinsufficiency of the T-box transcription factor gene TBX1 is thought to cause the phenotype , to date , only four different point mutations in TBX1 have been reported in association with six of the major features of 22q11.2 deletion syndrome .
O O O O B-GeneOrGeneProduct I-GeneOrGeneProduct I-GeneOrGeneProduct O B-GeneOrGeneProduct O O O O O O O O O O O O O O O O B-GeneOrGeneProduct O O O O O O O O O O O O B-DiseaseOrPhenotypicFeature I-DiseaseOrPhenotypicFeature I-DiseaseOrPhenotypicFeature O