22q11.2 deletion status and disease burden in children and adolescents with tetralogy of fallout

Circ Cardiovasc Genet. 2015 Feb;8(1):74-81. doi: 10.1161/CIRCGENETICS.114.000819. Epub 2015 Jan 5.

22q11.2 deletion status and disease burden in children and adolescents with tetralogy of fallot.

Mercer-Rosa L1Paridon SM1Fogel MA1Rychik J1Tanel RE1Zhao H1Zhang X1Yang W1Shults J1Goldmuntz E2.

Comment: Approximately 15% of patients with tetralogy of Fallot (TOF) have 22q11.2 deletion syndrome.  In this study Mercer-Rosa et al investigated the impact of 22q11.2 deletion on clinical outcomes among subjects in late childhood/adolescence (mean age 12.3 years).  This single institution cross-sectional study had the following inclusion criteria:  history of complete TOF repair, genetic screening for 22q11.2 deletion, and having undergone cardiac MRI and exercise testing within 3 months of each other.  Patients with other syndromic disorders (e.g. Down syndrome) were excluded. 

Abnormal exercise test findings, including reduced forced vital capacity (suggestive of restrictive lung disease), low maximal oxygen consumption, and impaired chronotropy, were frequently encountered within the entire study population (N=165).  Forced vital capacity and maximal oxygen consumption were significantly decreased among those with 22q11.2 deletion (n=27) compared with those without 22q11.2 deletion.  Clinically, patients with 22q11.2 deletion were more frequently hospitalized (for either cardiac or non-cardiac reasons) and required more cardiac and non-cardiac medications.  There was no difference in the number of cardiac procedures and no significant difference in cardiac MRI findings to explain the differential exercise performance between groups.  The investigators speculate that these observations reflect suboptimal routine exercise habits among children with TOF in general, which may be exacerbated in children with 22q11.2 deletion.