CLDN3 and hydrops fetalis: It is hypothesized that HF might affect intestinal barrier function and induce low-grade inflammation in the gut.33 In the colon of HF mice no changes were observed in gene expression levels of barrier proteins, Zonula occludens-1 (ZO-1), occludin, claudin-3 and mucin-2 (MUC2), as well as inflammatory markers, tumour necrosis factor-α (TNFα) and interleukin-6 (IL6) (see Supplementary material online, Figure S1D–H).