Abstract 1772: 22q11 Deletions in Adults With Tetralogy of Fallot Are Highly Under Recognized
Background The 22q11 microdeletion syndrome is the most common microdeletion syndrome in humans. It is characterized by cardiac and extracardiac manifestations, and is typically associated with conotruncal heart defects such as Tetralogy of Fallot (ToF). As the phenotype is highly variable in number and severity of associated features, the syndrome is thought to be under recognized, especially in adult patients. However, recognition of the syndrome is important, as many manifestations can be treated once detected and, moreover, because the offspring of a patient have a 50% chance of inheriting the 22q11 deletion.
Objective To determine the prevalence of 22q11 deletions in adult patients with ToF and to assess the level of recognition of the syndrome in these patients.
Methods Patients were identified from a nationwide registry and DNA bank which includes adults with congenital heart defects since 2001. Inclusion criteria were: registration before 2007, diagnosis of ToF or related cardiac defects, and availability of DNA. Patients with syndromes other than the 22q11 deletion syndrome were excluded. Multiplex Ligation-dependent Probe Amplification was used for detection of deletions or duplications.
Results 561 patients (56% male, median age 32.2 years (range 17.3 to 80.2 years) met the inclusion criteria, of whom 19 patients (3%) were already known with a 22q11 deletion before this study. We newly detected a 22q11 deletion in an additional 25 patients. Thus, in total, 44 of 567 patients (8%, 95% Confidence Interval 5.7 to 10.3) had a 22q11 deletion; 56% of these 22q11 deletions were unknown before this study.
Conclusion This study shows that the prevalence of 22q11 deletions in adults with ToF and related diagnoses is 8%, and, crucially, that the syndrome is highly under recognized. In conclusion, cardiologists should be aware of the high prevalence of 22q11 deletions in ToF patients, as this has significant clinical and reproductive implications. Consequently, a diagnostic test should be considered in all patients with ToF and related diagnoses.