Endocrine manifestations in DiGeorge and other microdeletion syndromes related to 22q11.2.

Microdeletions, translocations or other rearrangements of chromosomal region 22q11.2 have been reported in association with >80 different birth defects and malformations occurring in many combinations and with widely differing severity. Furthermore, a tendency to report atypical cases and ascertainment of published series according to the author’s speciality have resulted in the same deletion being linked to a heterogeneous group of disorders that share a common genetic basis, including the DiGeorge (DGS), velocardiofacial (or Shprintzen) (VCFS), and conotruncal anomaly face (CTAF) syndromes. Ninety percent of patients with DGS, 68% of VCFS, and 30% of CTAF patients are known to carry this deletion. The prevalence of DGS/VCFS is approximately 1:4.000 and they represent one of the most frequent genetic diseases, taking into consideration that this figure may be underestimated because of the rate of perinatal deaths observed in many cases with a severe congenital heart defect. The acronym “CATCH 22” (Cardiac anomalies, Abnormal face, Thymic hypoplasia, Cleft palate, and Hypocalcaemia) resulting from 22q11 deletions has also been proposed to describe the phenotype. Deletions on the short arm of chromosome 10 p13p14 are also associated with a DGS-like phenotype but are much less common than 22q11.2 deletions, occurring with an estimated frequency of 1 in 200,000 live births.