The EDC4 gene, also known as "Enhancer of Decapping 4," encodes a protein that plays a crucial role in the regulation of mRNA decay processes, particularly in the deadenylation-independent decapping of nuclear-transcribed mRNAs. Below are the detailed responses to your queries regarding EDC4:

### 1. Other Genes Associated with EDC4
EDC4 is part of a network of genes involved in mRNA decapping and degradation. Besides DCP2 and DCP1A, EDC4 may also be associated with:
- **XRN1**: A 5' to 3' exoribonuclease that is involved in mRNA degradation after decapping.
- **CSDE1**: Cold shock domain-containing protein that may interact with EDC4 and play a role in RNA metabolism.
- **RCK/p54**: An RNA-dependent ATPase that may be involved in ribonucleoprotein particle dynamics.
- **GW182**: A component of the miRNA silencing complex that associates with decapping factors.

### 2. EDC4 and Aging or Age-Related Diseases
While specific direct associations between EDC4 and aging or age-related diseases are not extensively documented, the role of mRNA decay in the regulation of protein synthesis suggests that EDC4 may indirectly influence cellular senescence, stress responses, and overall gene expression profiles associated with aging. Additionally, dysregulation of RNA metabolism has been implicated in several age-related diseases, including:
- **Neurodegenerative Diseases**: Altered mRNA turnover can contribute to the pathogenesis of disorders such as Alzheimer's Disease and Amyotrophic Lateral Sclerosis (ALS).
- **Cancer**: The misregulation of mRNA decay pathways, where EDC4 is involved, can lead to the stability of oncogenic mRNAs, contributing to tumorigenesis.

### 3. Drugs or Drug Classes Interacting with EDC4
Currently, there are no specific drugs or drug classes widely recognized as directly interacting with EDC4. However, since EDC4 is involved in mRNA decapping and degradation processes, drugs targeting pathways related to RNA metabolism, such as:
- **Antisense Oligonucleotides**: These may indirectly influence mRNA decay pathways.
- **Small Molecule Modulators**: Compounds that impact mRNA stability and translation may have effects on EDC4-related processes.
To determine specific drug interactions, further detailed drug screening studies focused on EDC4's function would be necessary.

### 4. Pathways and Biological Processes Involved
EDC4 is implicated in several key biological processes and pathways, including:
- **mRNA Decapping**: Plays a vital role in the removal of the 7-methylguanylate cap from mRNAs, facilitating degradation.
- **Regulation of Gene Expression**: Influences the stability and translation of mRNA.
- **RNA Metabolism**: Interacts in various aspects of pre-mRNA splicing and mRNA transport.
- **Nuclear mRNA Surveillance**: Part of pathways that monitor RNA quality and facilitate decay of defective mRNAs.
- **Cellular Response to Stress**: May be involved in regulating mRNA levels in response to environmental stressors.

In summary, EDC4 is an essential player in RNA metabolism, particularly in the decay of mRNA, with potential implications in aging, neurodegeneration, and cancer. The interaction pathways and associated genes illustrate a complex network involved in post-transcriptional regulation.