Because Slc7a7Lbu/Lbu mice showed greater postnatal growth failure with low plasma IGF-1 concentrations compared to the moderate IUGR in Slc7a7Lbu/Lbu embryos with normal plasma IGF-1 concentrations, subsequent skeletal phenotyping studies were only performed in P14-P18 WT and Slc7a7Lbu/Lbu mice. This evidence concerns the gene IGF1 and fetal growth restriction.