This A-to-T point mutation at position 982 of the Smad6 (SMAD family member 6) cDNA was identified in an ENU screen for recessive cardiovascular development phenotypes in Dr. Cecilia Lo's laboratory, NHLBI Cardiovascular Development Consortium (CvDC). It was recovered from G1 sperm and associated with the phenotype described described here. Because G1 sperm were cryopreserved, additional incidental mutations are also segregating in this strain.
Homozygotes demonstrate cardiovascular defects that involve a transposition of the great arteries (D-TGA), double outlet right ventricle (DORV), and ventricular septal defects (VSD).