### DECR2 Gene Overview

**Gene Symbol**: DECR2  
**Enzymatic Activity**: Enables 2,4-dienoyl-CoA reductase (NADPH) activity and trans-2-enoyl-CoA reductase (NADPH) activity.  
**Predicted Location**: Peroxisome  

**Function**: DECR2 encodes an auxiliary enzyme involved in the beta-oxidation pathway, particularly in the degradation of unsaturated fatty enoyl-CoA esters with double bonds in both even and odd-numbered positions. The enzyme catalyzes the NADP-dependent reduction of 2,4-dienoyl-CoA to yield trans-3-enoyl-CoA and shows activity towards short and medium chain 2,4-dienoyl-CoAs, as well as longer fatty acids such as docosahexaenoic acid (DHA). However, it does not appear to be a rate-limiting step in DHA degradation. 

### Additional Information

1. **Associated Genes**:
   - The DECR2 gene is often studied in the context of fatty acid metabolism and may have associations with other genes involved in lipid metabolic pathways, such as:
     - **ACOX1**: Acyl-CoA oxidase 1, involved in the first step of peroxisomal fatty acid beta-oxidation.
     - **EHHADH**: Enoyl-CoA hydratase, which acts on enoyl-CoA during beta-oxidation.
     - **FNBP1**: Formin binding protein 1, thought to interact with various metabolic enzymes but not necessarily linked in critical degradation processes.
 
2. **Aging and Age-Related Diseases**:
   - DECR2 has been implicated in pathways connected to the metabolism of unsaturated fatty acids, which can affect cellular lipid composition and energetic balance in aging cells.
   - There is ongoing research into the role of lipid metabolism in age-related diseases such as Alzheimer’s disease and cardiovascular disease, where alterations in fatty acid profiles may influence disease progression or susceptibility.

3. **Drug Interactions**:
   - As of the latest updates, there are no specific drugs or drug classes widely recognized to directly interact with DECR2. However, general research around enzymes in fatty acid metabolism might suggest interest in drugs targeting metabolic pathways in metabolic disorders or age-related conditions. Some antifibrotic agents or metabolic modulators might indirectly influence the activity but have not been explicitly linked.

4. **Pathways and Biological Processes**:
   - **Biological Processes**: 
     - Unsaturated fatty acid biosynthetic process
     - Beta-oxidation of fatty acids
     - Peroxisomal fatty acid metabolism
   - **Pathways**:
     - **Fatty acid degradation**: The DECR2 gene plays a direct role in the peroxisomal beta-oxidation of unsaturated fatty acids. 
     - **Lipid metabolism**: Related to the broader networks of lipid metabolism and energy homeostasis.

### Summary:
The DECR2 gene is critical for the proper metabolism of unsaturated fatty acids in peroxisomes, and though it is not a rate-limiting factor in the degradation of longer chain fatty acids like docosahexaenoic acid, its overall role in lipid metabolism is significant, especially within the context of aging and related diseases.