Microdeletion of chromosomal region 22q11 in DiGeorge syndrome: report of a case.

This is a case of chromosome 22q11 deletion in a female Chinese infant with DiGeorge syndrome. Cardiac anomalies included a type B interrupted aortic arch from the descending aorta with an aberrant right subclavian artery, a large ventricular septal defect, a small atrial septal defect and a large patent ductus arteriosus. This patient was small for her age and showed symptoms of feeding difficulties, chronic diarrhea and facial dysmorphisms (frontal bossing, hypertelorism, posteriorly rotated ears, fish-like mouth and micrognathia). Chest film did not reveal a thymic shadow. Immunological studies showed a low T-cell ratio (20%). Laboratory tests revealed a borderline low serum calcium level. The karyotype, 46, XX, del(22) (q11.21-->q11.23), was observed by high-resolution banding techniques. Cardiac surgery was successfully performed at 1 month of age. Operative findings confirmed aplasia of the thymus and the above complex cardiac anomalies. To our knowledge, this is the first Taiwanese case of DiGeorge syndrome proven immunologically and cytogenetically.