WNT1 and familial atrioventricular septal defect: Consistent with the conditional deletion of LRP1 in the neural crest lineage16 results in OFT defects (DORV with AVSD, DORV), a Cre lineage tracing of the neural crest cells, Wnt1-Cre16 with Rosa/LacZ reporter27, demonstrated decreased expression of the Wnt1/LacZ cells in the OFT at E10.5 embryos (Fig. 5q, r), which is consistent with the decrease in Wnt BAT-LacZ expression in the AV and OFT cushions of Lrp1m/m mutants (Fig. 5e–k).