The RPEL1 gene encodes a protein that plays a role in carbohydrate metabolism, specifically in the pentose phosphate pathway. Below is the requested comprehensive information regarding the RPEL1 gene:

### 1. Associated Genes:
While the summaries provided focus mainly on RPEL1 functions, several other genes may have connections through metabolic pathways or cellular processes. Some genes that may be associated with RPEL1 in various biological contexts include:

- **RPE (ribulose-phosphate 3-epimerase)**: Directly involved in the same epimerization process.
- **G6PD (glucose-6-phosphate dehydrogenase)**: An enzyme involved in the pentose phosphate pathway.
- **PGM (phosphoglucomutase)**: Participates in subsequent steps in carbohydrate metabolism.
- **TKT (transketolase)**: Another gene linked with the pentose phosphate pathway's non-oxidative branch.
  
### 2. Aging and Age-Related Diseases:
Research indicates that metabolic pathways, including the pentose phosphate pathway, play a role in the aging process and age-associated diseases. RPEL1's involvement in this pathway may position it as a factor in these contexts, though specific studies focusing explicitly on RPEL1 in aging or age-related diseases are limited:

- **Oxidative stress**: Components of the pentose phosphate pathway aid in the generation of NADPH, which is crucial for combating oxidative stress. Impairments here may relate to age-related decline and conditions like Alzheimer’s disease.
- **Cancer**: Aberrant regulation of carbohydrate metabolism and the pentose phosphate pathway is often implicated in cancer progression.

### 3. Drug Interactions:
At present, there may not be specific drugs directly targeting RPEL1; however, drugs that affect metabolic processes related to the pentose phosphate pathway could indirectly influence RPEL1 activity. Some classes of drugs involved in metabolic regulation include:

- **Antioxidants**: Drugs aimed at reducing oxidative stress may theoretically have an indirect effect by modulating pathways involving RPEL1.
- **Metabolic inhibitors**: Compounds that alter carbohydrate metabolism could impact cellular functions linked to RPEL1.

### 4. Pathways and Biological Processes:
RPEL1 is primarily involved in the following pathways and biological processes:

- **Pentose Phosphate Pathway (non-oxidative branch)**: Critical for nucleotide synthesis and reducing oxidative stress through the generation of NADPH.
- **Carbohydrate metabolic process**: General metabolism of carbohydrates, affecting energy production and biosynthesis of biomolecules.
- **Cellular carbohydrate metabolism**: Overall regulation of sugar metabolism in cells.
- **Ribulose-phosphate epimerization**: Converts D-ribulose 5-phosphate into D-xylulose 5-phosphate, a key step in the pentose phosphate pathway.

### Conclusion:
RPEL1 is significant in metabolic processes, particularly in the pentose phosphate pathway, impacting cellular health and may have implications in aging and certain diseases. Though direct drug interactions are not well established, its activity could influence responses to metabolic drugs and conditions.