rs11072566 — NRG4 NRG4 Variant

NRG4 — The Brown Fat–Liver Axis Regulator

NRG4¹¹ NRG4
Neuregulin 4, a member of the epidermal growth factor (EGF) family of extracellular signaling proteins is one of the primary secreted factors of brown adipose tissue (BAT) — a specialized fat depot that burns calories to generate heat. Unlike white fat, which stores energy, brown fat communicates with the liver via a class of secreted proteins called batokines. NRG4 is among the most potent of these signals: it travels from brown fat to liver hepatocytes, where it suppresses the production of new fat molecules. Lower NRG4 activity means more hepatic fat synthesis, higher circulating triglycerides, and greater risk of fatty liver disease.

The Mechanism

NRG4 binds to ErbB3 and ErbB4 receptor tyrosine kinases on hepatocyte surfaces, triggering a signaling cascade that suppresses LXR and SREBP-1c²² LXR and SREBP-1c
LXR (liver X receptor) and SREBP-1c (sterol regulatory element-binding protein 1c) are master transcription factors that switch on de novo lipogenesis — the liver's fat-manufacturing program — the liver's core lipid-manufacturing program. The net effect: less fat made in the liver, lower triglycerides exported into the bloodstream. rs11072566 is an intronic variant within the NRG4 gene on chromosome 15 (position 76,001,630, GRCh38). Intronic variants do not change the protein sequence but can influence splicing efficiency and gene expression levels; the specific regulatory effect of this variant on NRG4 transcription or splicing has not been directly measured in published eQTL studies. The G allele is the alternate allele (A is GRCh38 reference). In large-scale GWAS the rs11072566-A signal has been associated with red blood cell parameters (hematocrit, P=3×10⁻¹⁰), and the NRG4 region has been used as a genetic instrument for NRG4-mediated lipid levels in Mendelian randomization.

The Evidence

The foundational mechanistic work by Wang et al.³³ Wang et al.
Wang GX et al. The brown fat-enriched secreted factor Nrg4 preserves metabolic homeostasis through attenuation of hepatic lipogenesis. Nature Medicine, 2014 showed that Nrg4-knockout mice develop severe hepatic steatosis on a high-fat diet, while transgenic Nrg4 overexpression prevents diet-induced fatty liver. In human adipose tissue biopsies, NRG4 mRNA was inversely correlated with both body fat percentage and liver fat content. A subsequent study by Li et al.⁴⁴ Li et al.
Li Y et al. Mutations of NRG4 Contribute to the Pathogenesis of Nonalcoholic Fatty Liver Disease and Related Metabolic Disorders. Diabetes, 2021 identified rare NRG4 coding variants (R44H, E47Q) in 224 obese subjects with exome sequencing; the R44H variant lost hepatoprotective function, while E47Q enhanced it — providing direct human genetic evidence that NRG4 sequence variation alters hepatic lipid metabolism.

At the population level, a cross-sectional study in 1,212 obese Chinese adults⁵⁵ cross-sectional study in 1,212 obese Chinese adults
Cai C et al. Association of circulating neuregulin 4 with metabolic syndrome in obese adults. BMC Medicine, 2016 found that participants in the highest NRG4 quartile had significantly lower metabolic syndrome prevalence (57.4% vs 67.3%; adjusted OR 0.60; 95% CI 0.44–0.83). A systematic review and meta-analysis⁶⁶ systematic review and meta-analysis
Tapak MA et al. The impact of serum NRG-4 levels on NAFLD: a systematic review and meta-analysis. BMC Gastroenterol, 2025 pooling 631 participants found each unit increase in NRG-4 associated with approximately 28% lower NAFLD risk (OR 0.72; 95% CI 0.67–0.77). However, a key study by Martínez et al.⁷⁷ Martínez et al.
Martínez C et al. Serum neuregulin 4 is negatively correlated with insulin sensitivity in humans. Front Physiol, 2022 (n=89) found no significant associations between serum NRG4 levels and plasma triglycerides, LDL, or HDL — suggesting NRG4's influence on lipids may be more context-dependent and difficult to detect in small cross-sectional studies. Mendelian randomization using NRG4 locus SNPs in 1.32 million participants found NRG4-mediated LDL-C was nominally associated with peripheral atherosclerosis risk ⁸⁸ Zheng L et al. Causal Effect of Serum Lipid Levels Mediated by NRG4 on Atherosclerosis Subtypes. Vascular Health Risk Manag, 2024, though sensitivity analyses did not consistently replicate this finding. Because rs11072566 is intronic and lacks direct functional characterization, the evidence linking this specific variant to lipid outcomes remains emerging.

Practical Actions

The NRG4 system's leverage point is brown adipose tissue activity. Cold exposure, mild aerobic exercise, and diets low in saturated fat all support BAT thermogenesis and potentially NRG4 secretion — effects relevant to anyone with impaired NRG4 activity. For those carrying the G allele, reducing dietary saturated fat intake is the most directly supported strategy, since NRG4 deficiency specifically impairs the liver's response to lipogenic signals from saturated fatty acids. Monitoring fasting triglycerides and liver enzymes (ALT/AST) provides a window into hepatic lipid metabolism over time.

Interactions

NRG4 operates at the intersection of brown adipose tissue thermogenesis and hepatic lipid metabolism. Variants in genes regulating BAT activity (e.g., UCP1, ADRB3) or hepatic lipogenesis (FASN, ACACA) could theoretically compound or buffer NRG4 pathway effects, but no specific compound genotype interactions with rs11072566 have been studied. The broader NRG4 signaling network overlaps with APOB and APOC3 pathways in determining circulating triglyceride levels.