The GUCD1 gene encodes the guanine deaminase candidate 1 protein, which is believed to be involved in various cellular processes. Here is a detailed summary addressing your queries:

### 1. Associated Genes:
While the summaries from NCBI and UniProt do not explicitly list associated genes, GUCD1 may interact with other genes involved in metabolic pathways, particularly those related to nucleotide metabolism and guanine metabolism. Potential gene associations can sometimes be inferred from co-expression or protein-protein interaction data. However, specific direct interactions or associated genes often require targeted literature searches or pathway databases.

### 2. Aging and Age-Related Diseases:
As of the latest updates available until October 2023, direct evidence linking GUCD1 with aging or age-related diseases may not be well-established. However, given that genes associated with nucleotide metabolism can play roles in oxidative stress response and cellular maintenance, it is plausible that GUCD1 may indirectly influence age-related cellular decline or diseases such as neurodegenerative disorders. Studies aimed at understanding its pathway involvement may shed more light on this aspect.

### 3. Drug Interactions:
Currently, there is limited information regarding specific drugs or drug classes that interact directly with GUCD1. Most data on the drug interactions of specific genes typically come from databases cataloging pharmacogenomics information, and unless GUCD1 has been implicated in a drug metabolism pathway or is a target of specific therapeutics, it may not be associated with known drug interactions directly.

### 4. Pathways and Biological Processes:
GUCD1 is likely involved in several metabolic pathways, primarily associated with purine metabolism given its potential role in processing guanine. Some biological processes that may involve GUCD1 include:

- **Nucleotide Metabolism:** The conversion of guanine to other metabolites, affecting overall nucleotide pool balance.
- **Purine Catabolism:** Involvement in the breakdown of purines which is critical in maintaining cellular homeostasis.
- **Cellular Stress Responses:** Participation in pathways responsive to metabolic stresses might also be relevant.

In summary, while GUCD1 has a potential role in nucleotide metabolism, its precise biological functions, interactions with other genes, association with aging, drug interactions, and pathway involvements require more rigorous research for definitive conclusions. Further investigations into GUCD1's role in health and disease, especially in the context of aging, would be valuable to elucidate its biological significance.