We are undertaking a large-scale forward genetic screen in mice using chemical mutagenesis with ethyl nitrosourea (ENU) to recover mutations causing congenital heart defects. This screen was initiated in 2010 and is funded through the NHLBI Cardiovascular Development Consortium (CvDC) Bench to Bassinet program. The Bench to Bassinet program was established by NHLBI to foster innovative translational research in pediatric cardiovascular diseases.
The mission in our center is to develop new mutant mouse models for studying the genetic causes and developmental etiology of congenital heart defects. To accomplish this goal, in the coming five years we plan to ultrasound scan 100,000 mouse fetuses for an overall five fold genome coverage via a two generation backcross to recover recessive mutations causing congenital heart defects. Our screen is being conducted with a clinical ultrasound system, the Acuson Sequoia, using the 15 MHz 15L8 transducer. Follow up scans for more detailed diagnosis entails the use of the ultra high frequency Vevo 2100 biomicroscope with a 40 MHz transducer.
Mutants fetuses and pups identified as likely having structural heart defects will be recovered for necropsy, with the cardiac anatomy further evaluated by histopathology using episcopic fluorescence image capture (EFIC) imaging, Mouse Development Atlas and/or microCT analysis. The causative mutation will be identified using whole mouse genome sequencing analysis with next generation sequencing with the AB SOLiD. Through this large scale forward genetic screen, we expect to recover the large majority of genes likely to cause congenital heart disease.