The PRR5-ARHGAP8 gene represents a fusion of the PRR5 (proline-rich 5) and ARHGAP8 (Rho GTPase activating protein 8) genes. This gene is known for its unique mRNA and protein structure, incorporating elements from both parent genes while displaying features characteristic of a RhoGAP protein.

### 1. Associated Genes:
While the provided summaries mainly include the PRR5 and ARHGAP8 genes, the PRR5-ARHGAP8 fusion may functionally interact with genes involved in RhoA/ROCK signaling pathways, cytoskeletal dynamics, and any genes that regulate cellular signaling cascades influenced by Rho GTPases. Unfortunately, specific additional genes that directly associate with PRR5-ARHGAP8 have not been clearly defined in existing literature.

### 2. Aging and Age-Related Diseases:
There is currently limited information specifically connecting the PRR5-ARHGAP8 gene with aging or age-related diseases. However, given that Rho GTPase signaling pathways are known to play roles in cellular processes like migration, proliferation, and apoptosis, aberrations in this pathway may contribute to aging-related disorders or cancer. Future research may elucidate potential roles of the PRR5-ARHGAP8 product in age-related cellular changes.

### 3. Drug Interactions:
No direct drug interactions with the PRR5-ARHGAP8 gene have been reported in the current databases. However, since it is a part of Rho GTPase signaling pathways, drugs that target these pathways or related pathways, such as cytoskeleton-modifying agents, may have indirect effects on processes involving PRR5-ARHGAP8. Some drugs known to interfere with Rho GTPase signaling include:
- Statins (which can impact RhoA activity),
- Nocodazole and other microtubule inhibitors,
or drugs that act on pathways implicated in RhoA signaling.

### 4. Pathways and Biological Processes:
The PRR5-ARHGAP8 gene is thought to be involved in several biological processes, primarily through the activities of its individual components, PRR5 and ARHGAP8. Some of the pathways and processes include:
- **Regulation of the cytoskeleton:** Both PRR5 and ARHGAP8 impact actin dynamics, which are crucial for numerous cellular functions, such as migration, adhesion, and morphology.
- **Cell signaling pathways:** ARHGAP8 functions as a GTPase-activating protein, modulating Rho GTPases, which are important in various signaling pathways including those involved in cell adhesion and motility.
- **Cell proliferation and apoptosis:** Given the involvement of Rho GTPases in these physiological processes, PRR5-ARHGAP8 may also have roles in regulating these vital cellular activities.
- **Development and differentiation:** The presence of PRR5 indicates a probable role in cellular differentiation, which could impact tissue development and homeostasis.

Future detailed studies and experimental evidence will be essential to fully elucidate the functional implications of the PRR5-ARHGAP8 gene, including its relationships with aging, diseases, drug interactions, and specific biological roles.