This T-to-C point mutation at position 1645 of the Ift74 (intraflagellar transport 74) 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 heterotaxy syndrome (ambiguous lung lobation) with congenital heart disease (double outlet right ventricle (DORV), atrial-ventricular septal defect (AVSD) and dual inferior vena cava (IVC)).