The GCA gene, also known as "Glycosylation-Dependent Cell Adhesion Molecule," encodes a calcium-binding protein that is primarily found in immune cells such as neutrophils and macrophages. Below are additional pertinent details about the gene:

### 1. Gene Associations:
The GCA gene has associations with several other genes, particularly those that are involved in immune response, adhesion, and cytoskeletal dynamics. While specific genes may vary by research findings, potential associated genes include:
- **ITGB1 (Integrin Beta 1)**: Involved in cell adhesion and signaling.
- **CD44**: A cell surface glycoprotein involved in cell communication and adhesion to the extracellular matrix.
- **PDGFRA (Platelet-Derived Growth Factor Receptor Alpha)**: Relevant in cell proliferation and differentiation, which can be associated with immune response.

### 2. Aging and Age-Related Diseases:
Research has indicated that calcium signaling and dysregulation in calcium-binding proteins can be crucial in the aging process and age-related diseases. While specific studies directly linking GCA to aging or age-related conditions may be limited, calcium dysregulation has been implicated in:
- **Atherosclerosis**: Given its role in cell adhesion, the implications in immune cell function may be relevant in cardiovascular aging.
- **Alzheimer's Disease**: Calcium signaling disturbances are frequently associated with neurodegeneration.

### 3. Drug Interactions:
Direct drug interactions with GCA are not extensively documented; however, drugs or drug classes that may influence calcium signaling or cell adhesion could potentially impact the functionality of the GCA protein. Examples include:
- **Calcium Channel Blockers**: These could alter the calcium levels impacting GCA function.
- **Anti-inflammatory drugs**: Given GCA's role in immune responses, agents affecting inflammatory signaling may influence its activity.

### 4. Pathways and Biological Processes:
GCA is involved in several critical biological processes and pathways, which may include:
- **Cell Adhesion**: Particularly relevant in the immune response where GCA plays a part in neutrophil adhesion to fibronectin.
- **Focal Adhesion Formation**: This includes the assembly and maintenance of focal adhesions, linking the cytoskeleton to the extracellular matrix.
- **Cell Migration**: Through its involvement in cell adhesion and cytoskeletal dynamics, GCA likely participates in regulating neutrophil and macrophage migration.

### Additional Notes:
- **Alternative Splicing**: As mentioned in the summaries, GCA has multiple transcript variants, which may have different functions or regulatory roles.
- **Calcium Signaling**: The gene's dependence on calcium and magnesium suggests a broader role in cellular signaling and functional responses. 

Research into GCA remains vital for understanding its functions in immune responses and potential roles in disease, particularly concerning inflammation and cell adhesion mechanisms.