rs10838738 — MTCH2

MTCH2 — The Mitochondrial Gatekeeper of Fat and Energy

MTCH2 (Mitochondrial Carrier Homolog 2) encodes a protein embedded in the outer mitochondrial membrane that regulates how your cells burn fat versus store it. The rs10838738 variant is an intronic SNP that functions as a cis-eQTL¹¹ cis-eQTL
a genetic variant that affects the expression level of a nearby gene, increasing MTCH2 mRNA expression in adipose tissue. Higher MTCH2 levels tip the balance toward fat storage over fat oxidation.

The Mechanism

MTCH2 sits on the outer mitochondrial membrane where it directly regulates CPT1²² CPT1
carnitine palmitoyltransferase 1, the rate-limiting enzyme for fatty acid entry into mitochondria for oxidation. When MTCH2 is abundant, it increases CPT1 sensitivity to malonyl-CoA³³ malonyl-CoA
a metabolic intermediate that inhibits fat oxidation when energy is plentiful, effectively putting a brake on fatty acid oxidation. Conversely, when MTCH2 is reduced, CPT1 becomes less sensitive to malonyl-CoA inhibition, allowing increased fat burning.

The G allele at rs10838738 is in near-complete linkage disequilibrium (R² = 0.997) with rs1064608, which encodes a p.Pro290Ala⁴⁴ p.Pro290Ala
a proline-to-alanine substitution affecting protein function missense change in MTCH2. The G allele is associated with higher MTCH2 expression, leading to:

• Enhanced CPT1 malonyl-CoA sensitivity (reduced fat oxidation)
• Increased adipogenesis and lipid accumulation
• Reduced mitochondrial oxidative phosphorylation efficiency
• Lower overall energy expenditure

Mice lacking MTCH2 in muscle show increased whole-body energy utilization and protection from diet-induced obesity⁵⁵ increased whole-body energy utilization and protection from diet-induced obesity
Buzaglo-Azriel et al. Loss of Muscle MTCH2 Increases Whole-Body Energy Utilization and Protects from Diet-Induced Obesity. Cell Reports, 2016, demonstrating that MTCH2 reduction is metabolically favorable for weight management.

The Evidence

The GIANT consortium⁶⁶ GIANT consortium
Willer et al. Six new loci associated with body mass index highlight a neuronal influence on body weight regulation. Nature Genetics, 2009 meta-analysis of over 32,000 individuals identified MTCH2 as one of six genome-wide significant BMI loci (P = 1.9 x 10^-11). The per-allele BMI increase is approximately 0.07 kg/m^2.

A landmark study on opposing effects⁷⁷ landmark study on opposing effects
Fischer et al. Opposing effects of genetic variation in MTCH2 for obesity versus heart failure. Human Molecular Genetics, 2023 showed that while higher MTCH2 expression increases obesity risk, reduced MTCH2 expression may be disadvantageous during heart failure, where impaired glucose oxidation and increased lactate accumulation become problematic.

Recent work in adipogenesis⁸⁸ adipogenesis
Stein et al. MTCH2 controls energy demand and expenditure to fuel anabolism during adipogenesis. EMBO Journal, 2025 demonstrated that MTCH2 is essential for the energy shift from catabolism to anabolism during fat cell differentiation, controlling both energy demand and expenditure during this process.

Practical Actions

Because MTCH2 directly affects mitochondrial fat oxidation through CPT1 regulation, interventions that support mitochondrial function and fatty acid metabolism are particularly relevant for G allele carriers. Supporting the mitochondrial electron transport chain and facilitating fatty acid entry into mitochondria can help compensate for the variant's effect.

Interactions

MTCH2 rs10838738 contributes to polygenic obesity risk alongside FTO rs9939609, MC4R rs17782313, KCTD15 rs29941, and ETV5 rs7647305. The MTCH2 mechanism is unique among these — it directly affects mitochondrial fat oxidation rather than appetite regulation (MC4R, ETV5) or adipogenesis signaling (KCTD15). This makes it mechanistically complementary: an individual carrying risk alleles at both MTCH2 (reduced fat oxidation) and KCTD15 (enhanced adipogenesis) would face a compound effect on fat accumulation through two independent pathways.