### KIR2DS4 Gene Overview

**Gene Symbol**: KIR2DS4  
**Chromosomal Location**: Chromosome 19q13.4  
**Gene Type**: Killer Cell Immunoglobulin-like Receptor (KIR)

KIR2DS4 is part of a family of genes coding for receptors on natural killer (NK) cells. Unlike some KIR proteins that signal inhibitory responses, KIR2DS4 is categorized as an activating receptor, characterized by its short cytoplasmic tail. 

### 1. Associated Genes

In addition to the mentioned framework KIR genes (KIR3DL3, KIR3DP1, KIR3DL4, KIR3DL2), KIR2DS4 may also have interactions with the following:

- **HLA Genes**: KIR2DS4 specifically interacts with HLA-C alleles, which are a type of human leukocyte antigen that plays a critical role in immune regulation.
- **TYROBP (TYRO Protein Tyrosine Kinase Binding Protein)**: Though not an activating receptor, KIR2DS4 associates with this adaptor protein to mediate signaling.
- **Other KIR Genes**: Interaction exists at a genetic level due to the polymorphic nature and potential cross-talk among different KIR genes.

### 2. Aging and Age-Related Diseases

While direct associations between KIR2DS4 and aging are less robust in current literature, some studies have explored the relevance of KIR genes in the context of age-related immune changes. KIR2DS4 may impact:

- **Natural Killer Cell Dysfunction**: Aging affects NK cell activity, and the expression profiles of KIR may contribute to NK cell senescence or altered functionality in older adults. 
- **Autoimmune Conditions**: The KIR genes, including KIR2DS4, may play a role in the modulation of autoimmune diseases that can be exacerbated with age, although specific findings relating to KIR2DS4 require further validation.

### 3. Drug Interactions

Currently, there are no widely recognized drugs or drug classes that specifically target KIR2DS4. However, the following classes may interact indirectly based on the modulation of immune responses where KIR2DS4 is involved:

- **Immunomodulators**: Drugs that affect NK cell activity or the broader immune response, like monoclonal antibodies targeting immune checkpoints.
- **Antiviral therapies**: Some studies suggest that modulation of KIR expression may influence response to viral infections and supportive therapies in patients.

### 4. Biological Pathways and Processes

KIR2DS4 is involved in several important immunological processes, including:

- **Natural Killer Cell Activation**: KIR2DS4's primary role is to activate NK cells in the presence of specific HLA-C ligands.
- **Cytokine Production**: Involved in the modulation and secretion of cytokines that can alter immune responses.
- **Immune Surveillance**: Helps NK cells identify and eliminate tumor cells or virally infected cells.
- **Signal Transduction Pathways**: Mediates activating signals leading to NK cell activation via adaptor molecules like TYROBP.

**Overall**, KIR2DS4 represents a critical component of the immune system, possessing polymorphic features that allow for individual variability in immune response, influencing susceptibility to infections, autoimmunity, and potentially contributing to immune function changes in aging. Further research is required to clarify its role in specific diseases and therapeutic contexts.