HIF1A and periventricular leukomalacia: Moreover, because these two immunoregulatory angiogenic factors are also expressed in the CNS and Hif1-α specifically has a key role in angiogenesis in the CNS and myelination (Yuen et al., 2014), we hypothesize that in the HO-1-deficient fetus, these factors can adversely affect neurodevelopment and result in periventricular leukomalacia (PVL; Figure 2).