The PKHD1L1 gene encodes a protein involved in various biological processes, particularly those related to sensory perception and potentially playing roles in immune functions. Here’s a detailed overview of the gene, incorporating the additional points requested:

### 1. Associated Genes
PKHD1L1 has been shown to have associations with several other genes, although specific interactions can depend on context and specific biological processes being studied. Some genes that have been frequently associated with or studied alongside PKHD1L1 include:

- **PKHD1**: This gene encodes a protein associated with autosomal recessive polycystic kidney disease (ARPKD) and may share pathways with PKHD1L1 due to their similar nomenclature.
- **SLC7A9**: A member of the solute carrier family, which may interact in relation to renal functions.
- **ADAM17**: Known for its role in various signaling pathways and could potentially interact in T-cell activation scenarios given PKHD1L1's expression in activated T-cells.
  
### 2. Aging and Age-Related Diseases
PKHD1L1 has not been extensively characterized specifically in the context of aging or age-related diseases, but some insights can be drawn from its expression profile and potential functions:

- **Sensory Function**: Given its predicted role in sensory perception of sound, alterations in the expression or function of PKHD1L1 could potentially relate to age-related hearing loss or auditory processing disorders.
- **Immunity**: Its expression in activated T-cells and B-lymphoblasts suggests the gene could participate in immune responses that may be affected by aging (e.g., immunosenescence).
- **Kidney Function**: Although not directly linked to age-related diseases, the association with PKHD1 (which is involved in kidney disease) raises the possibility of implications in age-related decline in renal function if similar mechanisms were to apply.

### 3. Drug Interaction
As of now, specific drug interactions directly associated with PKHD1L1 have not been well-characterized in the literature. It is important to note that many pharmacologically relevant genes do not have a direct one-to-one drug interaction relationship unless they are specifically validated. However, it could be inferred that immune-modulating drugs might affect PKHD1L1 expression given its role in immune cells.

### 4. Pathways and Biological Processes
PKHD1L1 is likely involved in several biological processes and signaling pathways, including:

- **Sensory Perception**: Specifically related to sound perception, suggesting potential roles in auditory signal transduction pathways.
- **Immune Response**: Its expression in T-cells and B-cells points to involvement in adaptive immunity and possibly signaling pathways such as those activated during T-cell activation.
- **Cellular Signaling**: It may play roles in various intracellular signaling cascades that regulate cell proliferation, differentiation, and apoptosis, though the precise pathways remain to be fully elucidated.

### Conclusion
PKHD1L1 appears to have multifaceted roles, particularly in sensory perception and immune functions, which could have downstream effects related to aging and disease processes. However, more specific data about its interactions and roles in drug metabolism or pathways are still emerging and require further investigation.