Among individual variants, rs1260326 in GCKR and rs641738 in MBOAT7 (recessive), rs58542926 in TM6SF2 and rs738409 in PNPLA3 (dominant) emerged as associated to NAFLD, with PNPLA3 rs738409 being the strongest predictor (OR 3.12, 95% CI, 1.8-5.5, P < 0.001).
Because PNPLA3 rs738409, GCKR rs780094 and TM6SF2rs58542926 variants are known to confer susceptibility to NAFLD, we assessed the influence of MBOAT7 rs641738 on hepatic steatosis, and serum levels of CK-18 fragment (a biomarker of hepatocellular injury and apoptosis for NAFLD) after adjusting the effects of PNPLA3, GCKR and TM6SF2 polymorphisms.
We first demonstrated in childhood obesity the role of the MBOAT7 rs641738 variant on serum ALT and the combined effect of the MBOAT7, PNPLA3, and TM6SF2 variants on NAFLD risk.
We first review the association of TM6SF2 variant with plasma lipid traits, cardiovascular disease (CVD) and non-alcoholic fatty liver disease (NAFLD).
Here we show that adiposity significantly amplifies the effect of three sequence variants (encoding PNPLA3 p.I148M, TM6SF2p.E167K, and GCKR p.P446L) associated with nonalcoholic fatty liver disease (NAFLD).
Insulin resistance, the metabolic syndrome or type 2 diabetes and genetic variants of PNPLA3 or TM6SF2 seem to play a role in the pathogenesis of NAFLD.
The human transmembrane 6 superfamily member 2 (TM6SF2) gene has been implicated in plasma lipoprotein metabolism, alcoholic and non-alcoholic fatty liver disease and myocardial infarction in multiple genome-wide association studies.
Lean patients with rs738409 C>G in PNPLA3 should be monitored for liver disease progression; studies including large series of patients with lean NAFLD will clarify the possible role of TM6SF2 polymorphisms.
The number of PNPLA3, TM6SF2, and MBOAT7 risk variants was associated with NAFLD-HCC independently of clinical factors (p < 0.001), but did not significantly improve their predictive accuracy.
This study confirmed the genetic association of missense SNP of TM6SF2, rs58542926, with plasma lipid levels in multiple East Asian ethnic groups and with NAFLD in Japanese individuals.
This implies that NAFLD is heterogeneous and that "Obese/Metabolic NAFLD" but not NAFLD due to the PNPLA3 or TM6SF2 genetic variants predisposes to type 2 diabetes and cardiovascular disease.
A genome-wide exome association study has identified the transmembrane 6 superfamily member 2 (TM6SF2) rs58542926 variant encoding an E167K substitution as a genetic determinant of hepatic steatosis in nonalcoholic fatty liver disease (NAFLD).
The 167K allele in the TM6SF2 gene has been suggested to protect against cardiovascular disease at the cost of developing nonalcoholic fatty liver disease in adults.