A study reveals that upregulated expression of RELM gene in colonic epithelial cells drives elevated RELM levels in the serum of obese mice, and the latter is correlated to the degree of insulin resistance.[64] Meanwhile, research has shown that RELM‐β plays a critical role in maintaining colonic barrier function and innate gastrointestinal immunity.[65] In addition, “metabolic syndrome” was another important research theme at this stage. Here, RETNLB is linked to metabolic syndrome.