Prevalence of 22q11.2 microdeletion in 121 patients with cardiac malformation

BACKGROUND: It is known that 22q11.2 microdeletion is a submicroscopic chromosomal anomaly with cardiac and extra-cardiac manifestations. The prevalence and manifestations in north India have not been well characterized. OBJECTIVES: This study was designed to determine the prevalence of 22q11.2 microdeletion in congenital cardiac malformation cases referred for surgery from north India and to assess ability of clinical criteria to predict the presence or absence of 22q11.2 microdeletion. METHODS: A total of 121 cardiac malformation cases requiring surgery (conotruncal as well as non conotruncal heart defect) were prospectively screened for 22q11.2 microdeletion using fluorescence in situ hybridization test. Detailed clinical information was obtained from all cases. RESULTS: Four out of 121 patients (prevalence 3.3%) had 22q11.2 microdeletion (all with tetralogy of Fallot). In all of these four patients, typical dysmorphic features of 22q11.2 microdeletion were present. None of the cases with isolated cardiac defect (n=52) was positive for the deletion. CONCLUSIONS: Our work showed that 22q11.2 microdeletion is over-recognized with isolated congenital cardiac malformation. The absence of typical phenotypic features in cases of congenital cardiac malformation makes it difficult to justify investigation for deletion. Screening for 22q11.2 microdeletion should be considered in those cardiac malformation cases with extracardiac manifestations in particular facial dysmorphism.