Deletion 22q11.2 syndrome is the most frequent known microdeletion syndrome and is associated with a highly variable phenotype, including DiGeorge and Shprintzen (velocardiofacial) syndromes.
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.
Although, for the two truncating mutations, loss of function was previously shown, the pathomechanism of the missense mutations remains unknown.
Synopsis (exemples)
deletion 22q11.2 syndrome (D22S)
Di George syndrome
Tetralogy of Fallot
developmental delay
neural tube defects (NTDs)
velo-cardio-facial syndrome
DiGeorge sequence
congenital heart defect
minor facial anomalies
thymic hypoplasia
cleft lip and/or cleft palate
hypocalcemia
conotruncal heart defect
parathyroid gland dysfunction (16793949)
- hypocalcemic hypoparathyroidism (16793949)
See also
constitutional deletions