HIF1A and isolated hemihyperplasia: More mechanistic studies addressing these questions could now be envisioned in our mouse and cell culture models of IH, although we do recognize that the cell culture system is limited to studying EC responses, whereas gene profiling obtained from skin biopsies and whole aortas reflects the “transcriptome” of several cell types that can also modulate their expression of HIF-1α, and VEGF in response to IH.