Defective chromosome associated with De-George syndrome is -

Ans. is 'd' i.e., 22 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 disorders :-1) Di George syndromeThese patients have thymic hypoplasia with resultant T-cell immunodeficiency.Other features include parathyroid hypoplasia (causing hypocalcemia), cardiac malformations & facial anomalies.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) Veto cardio facial sndromeThis syndrome is characterized by facial dysmorphism (prominant nose, retrognathia), cleft palate, cardiovascular anomalies, and learning disabilities.