### MTHFS Gene Overview

**Gene Symbol:** MTHFS  
**Full Name:** Methylenetetrahydrofolate synthase (MTHFS)  
**Chromosomal Location:** Human chromosome location can vary, but MTHFS is typically found on chromosome 22.

#### Function
The MTHFS gene encodes an enzyme that is critical in the folate metabolism pathway. It catalyzes the conversion of 5-formyltetrahydrofolate (5-FTHF) to 5,10-methenyltetrahydrofolate, which is an essential precursor in the synthesis of reduced folates. This process plays a pivotal role in 1-carbon metabolism, which is crucial for the biosynthesis of purines, thymidine, and amino acids. 

#### Alternative Transcripts
There are three transcript variants identified for MTHFS that encode two different isoforms of the protein, indicating some complexity in its regulation and potential functional diversity.

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### 1. Associated Genes
MTHFS is involved in various metabolic pathways that overlap with several other genes, including:

- **MTHFR (Methylenetetrahydrofolate reductase)**: Plays a crucial role in converting 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate.
- **FDPS (Farnesyl diphosphate synthase)**: Implicated in metabolic pathways involving isoprenoid intermediates.
- **SHMT (Serine hydroxymethyltransferase)**: Involved in the conversion of serine and tetrahydrofolate to glycine and methylene-tetrahydrofolate.
- **DHFR (Dihydrofolate reductase)**: Catalyzes the reduction of dihydrofolate to tetrahydrofolate.

### 2. Aging and Age-related Diseases
Research has suggested that variations in MTHFS activity may have implications for aging and age-related diseases:

- **Cardiovascular diseases**: Altered folate metabolism may contribute to hyperhomocysteinemia, a risk factor for cardiovascular diseases. High levels of homocysteine are associated with cardiovascular events, and folate is critical in maintaining homocysteine levels.
- **Neurodegenerative diseases**: Folate metabolism is implicated in neurological health. Deficiencies or dysregulation in methylation processes involving folate may relate to conditions such as Alzheimer's disease.

### 3. Drug Interactions
While specific drugs targeting MTHFS are limited, it is involved in pathways modulated by:

- **Antifolate drugs**: Such as methotrexate, which inhibit folate-dependent enzymes, including DHFR. These drugs could potentially have downstream effects on MTHFS or be influenced by its activity.
- **Supplement interventions**: Folate supplementation may modulate the activity of MTHFS and thus affect the availability of folate in cycling pathways.

### 4. Pathways and Biological Processes
MTHFS is implicated in several key biochemical pathways and biological processes:

- **Folate metabolism**: Fundamental for nucleotide synthesis and amino acid metabolism.
- **One-carbon metabolism**: Essential for the transfer of one-carbon units, influencing DNA synthesis and repair.
- **Cell growth and division**: Adequate folate levels are crucial for cellular proliferation and maintenance, especially in rapidly dividing cells such as those in the bone marrow and skin.

#### Key Pathways:
- **Purine metabolism**
- **Thymidine metabolism**
- **Amino acid biosynthesis and metabolism (e.g., serine and glycine metabolism)**

In summary, the MTHFS gene is integral to folate metabolism, influencing various biological processes and potentially affecting health outcomes related to aging and disease. Its interactions with other genes and potential drug influences highlight its importance in metabolic regulation.