Genetic Testing for Congenital Heart Disease
Early detection and diagnosis of Congenital Heart Defects (CHDs) is essential to guide patient care. Survival and medical care for children with CHDs are improving. Among states with mandatory CHD screening via pulse oximetry, a 33.4% reduction of early infant deaths due to CHD was observed (Abouk et al., 2017). Initial diagnosis is only the beginning. Genetic testing for CHD also plays an important role in improving outcomes.
Determining the genetic cause of congenital heart disease can provide a more accurate prognosis by providing insight into potential unanticipated extracardiac involvement, other associated cardiac complications, and long-term outcomes (Chaix et al., 2016). Genetic testing for congenital heart defects may also provide the ability to assess recurrence risk in future pregnancies. In a prenatal setting, genetic diagnosis of CHDs can have a substantial impact on neonatal outcomes and medical support (van Nesselrooij, 2020).
About Congenital Heart Defects
CHDs are structural defects of the heart that arise during development and are among the most common birth defects, occurring in 6-10 children per 1000 live births (Hoffman, 2002). CHDs are most commonly isolated; however, they can also present in a wide range of syndromes.
Structural defects can include, but are not limited to:
• Conotruncal abnormalities (tetralogy of Fallot, double-outlet right ventricle (DORV), truncus arteriosus, transposition of the great arteries (TGA))
• Left ventricular outflow tract obstruction (coarctation of the aorta, aortic valve stenosis, bicuspid aortic valve, hypoplastic left heart)
• Septal defects
The severity of CHDs ranges greatly. Some CHDs are considered minor or even self-resolving, while others are classified as critical congenital heart disease and require surgery within the first days to year of life (Chaix, 2016).
Tests for Congenital Heart Disease at PreventionGenetics
Two new sequencing panels for congenital heart defects are available on PreventionGenetics' menu: a larger 398 gene Comprehensive Congenital Heart Disease Panel and a 44 gene Nonsyndromic Congenital Heart Disease Panel. The comprehensive panel includes exome-wide CNV, which allows for cost-effective identification and reporting of potentially important, large CNVs across the full exome, similar to those detected by chromosomal microarray (CMA). See individual test descriptions for more information about these tests.
In addition to the CHD panels, PreventionGenetics also offers genetic tests for many of the syndromes associated with congenital heart defects. Approximately 30% of CHDs are associated with a syndrome (Chaix et al., 2016). The genes associated with these syndromes are included in the Comprehensive Congenital Heart Disease panel, however, based on clinical features one of the smaller panels may be appropriate.
|Additional Testing Options|
|Alagille Syndrome Panel|
|Brugada Syndrome Panel|
|Kabuki Syndrome Panel|
|Holt-Oram Syndrome (HOS) Testing via TBX5 Sequencing|
|Noonan Spectrum Disorders/Rasopathies Panel|
For those who prefer genomes or exomes rather than defined panels, PreventionGenetics provides a number of options. PGnome? and PGxome? are available now with a standard turnaround time of 30 days. Rapid and prenatal PGxome options are also currently available with an average turnaround time of 14 days on average. Rapid and prenatal versions of PGnome will also be available later this year.
|PGnome Diagnostic||PGxome Diagnostic|
Abouk et al. 2017. PubMed ID: 29209720
Chaix et al. 2016. PubMed ID: 26981213
Cirino et al. 2017. PubMed ID: 28793145
van Nesselrooij et al. 2020. PubMed ID: 32341573