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MECR
mitochondrial trans-2-enoyl-CoA reductase
MECR is located on the short (p) arm of chromosome 1, at band 1p35.3. Arm ratio per GRCh38 - banding schematic.
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Overview
MECR (mitochondrial trans-2-enoyl-CoA reductase) encodes an enzyme that catalyses a specific step in fatty acid synthesis within mitochondria. Whilst most fatty acid production occurs in the cytoplasm, mitochondria maintain their own pathway for generating certain fatty acids needed for membrane structure and metabolic regulation. The MECR enzyme reduces trans-2-enoyl-CoA intermediates, a necessary reaction for completing the synthesis of these specialised lipids.
This mitochondrial pathway is particularly important for tissues with high energy demands, such as the brain, heart, and skeletal muscle. Because mitochondrial function underpins cellular energy production, disruption to MECR activity can have wide-ranging effects on metabolism and tissue health.
What the gene does
The MECR protein functions as a reductase enzyme, catalysing the reduction of carbon-carbon double bonds in fatty acid precursors. Specifically, it converts trans-2-enoyl-CoA molecules to saturated acyl-CoA products, a reaction that requires NADH as a cofactor to donate electrons. This enzymatic activity is essential for the mitochondrial fatty acid synthesis pathway, which differs from the better-known cytoplasmic fatty acid synthesis machinery.
Mitochondrial fatty acids serve distinct biological roles compared with those made in the cytoplasm. They contribute to the inner mitochondrial membrane lipid composition, influence membrane protein function, and may participate in signalling pathways that regulate cellular metabolism. The MECR enzyme operates within the mitochondrial matrix, where it works alongside other enzymes to construct these specialised lipids. Proper mitochondrial fatty acid synthesis is thought to support efficient energy production through oxidative phosphorylation, particularly in metabolically active tissues.
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Chromosome location
The MECR gene is located on the short arm of chromosome 1 at position p35.3. This chromosomal region contains numerous genes involved in basic cellular processes. The precise number of exons and overall gene structure for MECR have not been extensively characterised in publicly available databases, though the gene produces a functional protein localised to mitochondria.
Protein structure
Domain architecture has not been experimentally characterised in detail for this protein.
Key variants
Genetic variants in MECR can alter the enzyme's ability to catalyse fatty acid synthesis within mitochondria. Because the inheritance pattern varies depending on the specific variant and clinical context, different types of pathogenic changes may produce different patterns of disease transmission. Some variants may reduce enzyme activity through effects on protein stability, whilst others might interfere with the enzyme's catalytic function or its ability to interact with cofactors.
Sample of pathogenic variants
10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.
| Variant (HGVS) | Protein change | Classification | Evidence | Associated condition |
|---|---|---|---|---|
c.772C>T | p.Arg258Trp | Pathogenic | ★★☆☆ | MECR-related disorder |
c.247_250del | p.Asn83fs | Pathogenic | ★★☆☆ | Dystonia, childhood-onset, with optic atrophy and basal ganglia abnormalities |
c.695G>A | p.Gly232Glu | Pathogenic/Likely pathogenic | ★★☆☆ | Dystonia, childhood-onset, with optic atrophy and basal ganglia abnormalities |
c.830+2dup | - | Pathogenic/Likely pathogenic | ★★☆☆ | Mitochondrial disease |
c.855T>G | p.Tyr285Ter | Pathogenic | ★★☆☆ | not provided |
g.(?_29520534)_(29543217_?)del | - | Pathogenic | ★☆☆☆ | not provided |
g.(?_29527008)_(29527121_?)del | - | Pathogenic | ★☆☆☆ | not provided |
g.(?_29542497)_(29543217_?)del | - | Pathogenic | ★☆☆☆ | not provided |
c.39dup | p.Ala14fs | Pathogenic | ★☆☆☆ | not provided |
c.861dup | p.Met288fs | Pathogenic | ★☆☆☆ | not provided |
Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.
Associated conditions
Changes in MECR have been linked to mitochondrial dysfunction affecting multiple organ systems, though specific disease associations remain under investigation. Because mitochondrial fatty acid synthesis supports cellular energy production, disruption to MECR activity may affect tissues with high metabolic demands. The clinical presentation associated with MECR variants can vary, reflecting the gene's role in fundamental metabolic processes that influence multiple tissues and developmental stages.
No disease links recorded for this gene in our reference set.
UK clinical status
Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory
Frequently asked questions
What does the MECR gene do?
MECR provides instructions for making an enzyme that catalyses a key step in fatty acid synthesis within mitochondria. This enzyme helps produce specialised fatty acids needed for mitochondrial membrane structure and metabolic function, particularly in energy-demanding tissues like the brain and heart.
Where is the MECR gene located?
The MECR gene is located on chromosome 1 at position p35.3, on the short arm of the chromosome. This region contains various genes involved in fundamental cellular processes.
How are MECR variants inherited?
The inheritance pattern for MECR variants can vary depending on the specific genetic change and clinical context. Some pathogenic variants may follow autosomal recessive inheritance, whilst others might show different patterns, so genetic counselling can help clarify inheritance for individual families.