Defective chromosome associated with De-George syndrome is?

Ans. is 'd' i.e., 22 Chromosome 22q 11.2 deletion syndromeo This syndrome encompasses a spectrum of disorders that result from a small deletion of band q 11.2 on long arm of chromosome 22. Clinical features are considered to represent two different disorders1) Di George syndromeo These patients have thymic hypoplasia with resultant T-cell immunodeficiency.o Other features include parathyroid hypoplasia (causing hypocalcemia), cardiac malformations & facial anomalies.o TBX-1 gene (a T-box transcription factor) is most closely associated with this syndrome. The target of TBX-1 include PAX 9, a gene that controls the development of the palate, parathyroid and thymus.2) Velo cardio facial sndromeo This syndrome is characterized by facial dysmorphism (prominant nose, retrognathia), cleft palate, cardiovascular anomalies, and learning disabilities.