rs11868035 — SREBF1

SREBF1 rs11868035 — When the Fat-Building Switch Runs Too Hot

Deep inside your liver cells, a protein called SREBP-1c acts as the master switch for de novo lipogenesis¹¹ de novo lipogenesis
De novo lipogenesis: the biochemical process by which the liver converts carbohydrates into fatty acids and triglycerides for storage. Under normal conditions, insulin turns this switch on after meals — signaling the liver to convert surplus glucose into fat. The rs11868035 variant in the SREBF1 gene alters the regulation of this switch, tipping carriers toward higher triglyceride synthesis, impaired insulin signaling, and a modestly elevated risk of type 2 diabetes.

The Mechanism

SREBF1 (Sterol Regulatory Element Binding Transcription Factor 1) encodes two isoforms from the same locus through alternative promoter usage: SREBP-1a (a broadly expressed, potent transactivator) and SREBP-1c (the liver- and fat-tissue-dominant form that is the primary target of insulin signaling). rs11868035 sits in the 3' UTR and intronic regions of SREBF1, where variants can influence mRNA stability, splicing efficiency, and ultimately protein expression levels of SREBP-1c.

SREBP-1c is synthesized as an inactive precursor anchored to the endoplasmic reticulum. When insulin rises after a meal, the PI3K/Akt pathway triggers its proteolytic cleavage, allowing the mature SREBP-1c fragment to enter the nucleus and activate transcription of lipogenic genes — including fatty acid synthase (FASN), acetyl-CoA carboxylase (ACC), and stearoyl-CoA desaturase (SCD1). The rs11868035 risk variant is associated with altered SREBP-1c activity, promoting greater hepatic fat synthesis and contributing to the insulin-resistance cycle: excess hepatic lipid accumulation impairs insulin receptor signaling, further dysregulating glucose and lipid homeostasis.

The Evidence

The most robust human evidence comes from a 15,734-subject Danish cohort study²² 15,734-subject Danish cohort study
Grarup N et al. Diabetes 2008 that linked the minor alleles of rs11868035 and two co-inherited variants (rs2297508, rs1889018; R²=0.6–0.8) to a modestly elevated T2DM risk. For the best-characterized linked variant rs2297508, the per-allele OR for diabetes was 1.17 (95% CI 1.05–1.30, p=0.003); meta-analysis across an additional cohort produced OR 1.08 per allele (p=0.001). Crucially, the risk alleles also associated with elevated plasma glucose at 30 and 120 minutes³³ elevated plasma glucose at 30 and 120 minutes
and elevated serum insulin at 120 min during oral glucose tolerance testing (p<0.006), pointing to impaired glucose clearance rather than fasting hyperglycemia alone.

A Chinese cohort study⁴⁴ Chinese cohort study
Liu JX et al. Diabetes Res Clin Pract 2008 of 327 subjects found significant differences in rs11868035 genotype and allele distributions between T2DM patients and controls (p=0.013 and p=0.001 respectively), and the risk allele was associated with higher LDL cholesterol — consistent with SREBP-1c's role in both triglyceride and cholesterol synthesis. This finding was replicated across a larger 1,141-subject Han and Dongxiang Chinese cohort⁵⁵ 1,141-subject Han and Dongxiang Chinese cohort
Liu JX et al. Zhonghua Yi Xue Yi Chuan Xue Za Zhi 2012 where the risk allele was identified as a T2DM risk factor in both ethnic groups.

For liver health, a liver stiffness study⁶⁶ liver stiffness study
Müller M et al. Int J Mol Sci 2013 found that risk-allele carriers had significantly higher liver stiffness scores (p=0.029), and the combined effect of carrying both the SREBP1c and PNPLA3 risk genotypes produced substantially greater liver stiffness (p=0.005), suggesting a synergistic lipogenic pathway.

A triglyceride link emerged from a Chinese NAFLD study⁷⁷ Chinese NAFLD study
Peng XE et al. Sci Rep 2016 where the G allele (protective genotype on plus strand) was associated with lower triglyceride levels in healthy controls (p<0.01), and from a Mexican ACS cohort⁸⁸ Mexican ACS cohort
Vargas-Alarcón G et al. PLoS One 2019 showing significant association between rs11868035 and plasma triglyceride levels.

A pharmacogenomics study in 157 schizophrenia patients⁹⁹ 157 schizophrenia patients
Vassas TJ et al. Pharmacogenomics 2014 found that risk-allele carriers had significantly elevated total cholesterol (p=0.01), LDL (p=0.03), and triglycerides (p=0.04) despite statin therapy, suggesting the variant may attenuate statin efficacy — an important clinical consideration.

Practical Actions

The SREBP-1c pathway is acutely responsive to dietary carbohydrate load. Because SREBP-1c is the primary executor of insulin-stimulated lipogenesis, carriers of the risk allele benefit most from strategies that reduce postprandial insulin spikes: limiting refined carbohydrates and added sugars directly curtails the insulin signal that activates SREBP-1c. Monitoring fasting triglycerides and non-HDL cholesterol provides a lipid-specific window into SREBP-1c activity. HbA1c monitoring tracks the slower trajectory toward glucose dysregulation.

The statin-interaction finding warrants attention: if lipid control is inadequate on standard statin doses, the rs11868035 variant may be contributing — a conversation worth having with the prescribing physician.

Interactions

rs11868035 sits in the same lipogenic pathway as PNPLA3 (rs738409), a hepatic lipase variant strongly linked to NAFLD and liver fibrosis. The Müller 2013 study demonstrated that carriers of both variants showed substantially greater liver stiffness than carriers of either alone, suggesting a compound lipogenic burden. This interaction is a strong candidate for a compound action.

Within the SREBP-1c regulatory network, insulin receptor signaling variants (ENPP1 rs1044498, IRS-1 rs2943641) upstream of SREBP-1c activation can compound the downstream lipogenic dysregulation associated with rs11868035.