====== GSTM1 ======

### **GSTM1 (Glutathione S-Transferase Mu 1) Gene**
The **GSTM1** gene is located on **chromosome 1p13.3**. However, it's an important gene involved in detoxification processes in the human body.

### **Function of GSTM1**
- The **GSTM1** gene encodes **Glutathione S-Transferase Mu 1 (GSTM1)**, an enzyme that plays a key role in **detoxification** by conjugating **glutathione (GSH)** to various harmful compounds, including:
  - Carcinogens
  - Drugs
  - Environmental toxins
  - Oxidative stress byproducts

- This enzyme helps in **phase II metabolism** of xenobiotics, making toxic compounds more water-soluble and easier to excrete.

### **GSTM1 Null Polymorphism**
One of the most notable features of **GSTM1** is its **common deletion polymorphism** (GSTM1 *null genotype*), which means:
- Some individuals **completely lack** a functional **GSTM1** gene due to a **homozygous deletion**.
- The absence of **GSTM1** enzyme activity is associated with **reduced detoxification capacity**.

### **Health Implications of the GSTM1 Null Genotype**
The **GSTM1 null genotype** has been linked to various health conditions, including:

#### **Increased Cancer Risk**
- Individuals with **GSTM1 null** may have an **increased susceptibility** to cancers, particularly:
  - **Lung cancer** (especially in smokers)
  - **Bladder cancer**
  - **Breast cancer**
  - **Colorectal cancer**

#### **Respiratory and Cardiovascular Diseases**
- Reduced detoxification of **airborne pollutants** and oxidative stress may contribute to:
  - **Asthma**
  - **Chronic Obstructive Pulmonary Disease (COPD)**
  - **Atherosclerosis**

#### **Drug Metabolism**
- The GSTM1-null genotype can affect **drug metabolism**, influencing how individuals respond to **chemotherapy drugs** and other medications.

#### **Neurodegenerative Disorders**
- Some studies suggest a link between **GSTM1-null** and **Parkinson's disease** or **Alzheimer's disease**, possibly due to impaired antioxidant defense.

### **Clinical and Genetic Testing**
- **GSTM1 deletion testing** is available as part of pharmacogenetic and cancer risk assessments.
- Understanding GSTM1 status can help personalize **cancer prevention strategies**, **environmental exposure precautions**, and **drug therapy choices**.