The **EHD4 gene** (EH domain containing 4) encodes a protein that plays a critical role in various cellular processes, particularly in the context of endocytic recycling and membrane trafficking. Below are detailed descriptions pertaining to your requests.

### 1. Associated Genes
While specific genes directly associated with EHD4 are not extensively detailed in the summaries, there are proteins within related pathways and processes that could show potential interactions, including:
- **EHD1/EHD2/EHD3**: Members of the EHD family that share structural and functional similarities.
- **CLTC (Clathrin heavy chain)**: Involved in clathrin-mediated endocytosis which could interact with EHD4 during membrane trafficking.
- **RAB proteins (e.g., RAB4A, RAB11A)**: Involved in vesicle trafficking which can be associated with the recycling endosome pathway where EHD4 operates.

### 2. Aging and Age-Related Diseases
Research indicates that endosomal dysfunction may play a role in various age-related conditions. Although specific connections between EHD4 and aging are still under investigation, misregulation of endocytic pathways involving proteins including EHD4 can contribute to:
- Neurodegenerative diseases (e.g., Alzheimer's disease) where endocytic recycling is disrupted.
- Age-related changes in tissue homeostasis due to impaired membrane trafficking and degradation processes.

Additional studies are warranted to clarify the direct implications of EHD4 in these conditions.

### 3. Drug Interactions
Currently, specific drugs or drug classes that interact directly with the EHD4 protein have not been clearly characterized in the literature. However, since EHD4 is involved in cellular processes such as endocytic recycling and potentially influences pathways affected in various diseases (like cancer or neurodegeneration), compounds targeting generic pathways of endocytosis and cellular trafficking could indirectly influence EHD4 activity. 

### 4. Involved Pathways and Biological Processes
EHD4 participates in several biological processes and pathways, including:
- **Endocytosis**: It plays a significant role in the transport of membrane proteins through the endosomal system, specifically in the recycling of proteins back to the plasma membrane.
- **Membrane dynamics**: The protein facilitates membrane tubulation and reorganization in response to ATP hydrolysis, indicating its function in membrane tethering and fusion processes.
- **Protein oligomerization**: Mediation of protein-protein interactions influencing the stability and functionality of other membrane-associated proteins.
- **Cell adhesion**: As it enables cadherin binding activity, it may have roles in maintaining cell adhesion and communications.

Overall, the EHD4 gene is critical in maintaining proper cellular functions related to membrane trafficking, and its dysregulation may have implications in various diseases, especially those associated with aging. Further studies are necessary to elucidate its exact roles and potential as a therapeutic target.