### KHK Gene Overview

**Gene Symbol**: KHK

**Description**: The KHK gene encodes ketohexokinase, an enzyme that catalyzes the phosphorylation of fructose to fructose-1-phosphate. This reaction initiates the metabolism of dietary fructose through a specialized catabolic pathway. The gene undergoes alternative splicing, resulting in various isoforms that may have distinct functional properties.

### 1. Associated Genes

The KHK gene is associated with several other genes involved in fructose metabolism and related pathways:

- **ALDOB** (Aldolase B): Plays a role in the metabolism of fructose and is critical in glycolysis and gluconeogenesis.
- **FUA** (Fructose-bisphosphate aldolase, class I): Involved in the conversion of fructose-1-phosphate.
- **PFKFB3** (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3): Regulates glycolysis in response to fructose levels.
- **GAPDH** (Glyceraldehyde-3-phosphate dehydrogenase): Participates in gluconeogenesis and glycolysis, processes linked to fructose metabolism.
  
### 2. Aging or Age-Related Disease Associations

KHK has been implicated in certain aspects of aging and age-related diseases, especially concerning metabolic dysfunctions:

- **Metabolic Syndrome**: Dysregulation of fructose metabolism due to KHK activity can contribute to conditions such as obesity, insulin resistance, and type 2 diabetes.
- **Non-alcoholic fatty liver disease (NAFLD)**: Increased dietary fructose, which is metabolized by KHK, is linked with an increase in hepatic fat accumulation.
- **Aging**: There is emerging evidence that aberrant fructose metabolism can contribute to age-related metabolic decline, including alterations in lipid metabolism and inflammation.

### 3. Drug or Drug Classes Interactions

While specific drugs targeting KHK directly are not widely reported, the following interactions related to its metabolic pathway may be relevant:

- **Fructose absorption inhibitors**: Though not acting directly on KHK, drugs that inhibit fructose absorption may indirectly reduce KHK substrate availability.
- **Antidiabetic drugs**: Some diabetes treatment modalities might influence fructose metabolism indirectly. For example, metformin, which modulates glucose levels and may influence metabolic pathways interconnected with fructose metabolism via KHK.

### 4. Pathways and Biological Processes

The KHK gene is involved in several key metabolic pathways and biological processes:

- **Fructose Metabolism**: Directly involved in the fructose catabolic pathway, converting fructose to fructose-1-phosphate, which is further metabolized via glycolysis.
- **Glycolysis**: Plays a critical role in the breakdown of sugars to produce energy.
- **Carbohydrate Metabolic Process**: Integral to the overall metabolism of carbohydrates, particularly focusing on pentose and hexose sugar metabolism.
- **Hexose Metabolism**: KHK specifically converts ketoses, emphasizing its role in hexose kinases.

In summary, the KHK gene is essential for fructose metabolism and influences various metabolic processes and diseases. Understanding its interactions and pathways can provide insights into conditions influenced by dietary sugars and associated metabolic disorders.