IGFL1 and pulmonary hypertension: However, this study found a positive association between hypertension and methylation at a CpG site in the promoter region of Igfl1 and at several sites in Fgfr2, Rhoc, and Notch1, but not in Med1. A different CpG site in the promoter region of Igfl1 showed a similar trend in a different study, with methylation positively correlated with pulmonary hypertension [41].