IGFBP1 and hypoalphalipoproteinemia, primary, 1: The data showed that non-diabetic control subjects with FHD had similar IGFBP1 DNA methylation levels (16.9% and 17.0%) but lower serum protein levels compared with those without FHD (19 vs. 25 μg/L, P = 0.018) (Figure 2A and2B).