NRG4 and metabolic syndrome: As shown in Fig. 1, serum Nrg4 levels were significantly reduced in subjects with raised fasting glucose (3.21 (2.38–4.58) vs. 3.53 (2.60–5.05), P < 0.001), raised BP (3.24 (2.37–4.59) vs. 3.49 (2.60–5.05), P < 0.05), or presence of MetS (3.24 (2.40–4.52) vs. 3.68 (2.62–5.53), P < 0.001) compared to their controls, adjusted for age, gender and BMI.