SERPING1 and hereditary angioedema: Considering the lack of evidence for differential epigenetic regulation at the DNA methylation level of promoter activity in the SERPING1 locus in HAE patients’ PBMCs, the fact that the demethylating agents 5'Aza-dC and TSA strongly increased mRNA and protein synthesis in Huh7 cells could reflect an upstream indirect epigenetic regulation of trans-acting factors like transcription factors or microRNAs in the hepatocyte.