Incidences of micro-deletion/duplication 22q11.2 detected by multiplex ligation-dependent probe amplification in patients with congenital cardiac disease who are scheduled for cardiac surgery.

BACKGROUND

22q11.2 microdeletion is the most common microdeletion in the global population. Congenital cardiac disease is the most frequently observed feature of this syndrome. The prognosis of patients with 22q11.2 copy number aberrations varies from those without 22q11.2 deletion or duplication.

METHODS

We enrolled 241 patients from Nanjing Drum Tower Hospital and Nanjing Sick Children's Hospital, 227 being scheduled for cardiac surgery, and 14 cases being fetuses aged from 24 to 36 gestational weeks. We performed karyotypic analysis and multiplex ligation-dependent probe amplification in all cases.

RESULTS

Karyotypic analysis demonstrated 3 cases with trisomy 21, and 1 case with mosaic trisomy 8 [47,XY,+8/46,XY(1:2)]. Multiplex ligation-dependent probe amplification analysis revealed 10 cases (4.15%) with changes in the number of copies within the region of 22q11.2, of which 7 cases were hemizygous interstitial microdeletion from CLTCL1 to LZTR1, 1 case with deletion of the region from CLTCL1 to PCQAP, and 2 cases with 22q11.2 duplication, one of which spanned from ZNF74 to LZTR1, and simultaneously showed trisomy 21 by karyotyping analysis, and the other spanned from HIC2 to TOP3B. The phenotypes of the cardiac lesions included 3 cases of ventricular septal defect, 3 of tetralogy of Fallot, 2 of combined ventricular and atrial septal defects, and 2 with pulmonary arterial stenosis.

CONCLUSIONS

Patients with congenitally malformed hearts who are scheduled for cardiac surgery, as well as fetuses with congenital cardiac disease, should routinely undergo karyotypic analysis and examination for 22q11.2 aberrations. Multiplex ligation-dependent probe amplification has been proven to be a cost-effective diagnostic technique for 22q11 deletion syndrome.