====== Chromosome 5 ======

**Chromosome 5** is one of the 23 pairs of human chromosomes and is classified as an autosome. Here are some key facts about it:

### **General Characteristics**
- **Size**: Chromosome 5 is one of the larger chromosomes, spanning approximately **181 million base pairs**.
- **Gene Content**: It contains around **900-1,000** protein-coding genes.
- **Location of Centromere**: It has a **submetacentric** centromere, meaning it has one arm slightly longer than the other.

### **Significant Genes**
Chromosome 5 houses several important genes involved in various biological functions, including:
- **APC (Adenomatous Polyposis Coli)**: A tumor suppressor gene associated with colorectal cancer.
- **EGR1 (Early Growth Response 1)**: A gene that plays a role in cell growth and differentiation.
- **SLC9A3 (Sodium/Hydrogen Exchanger 3)**: Important for kidney function and acid-base balance.
- **SMN1 & SMN2 (Survival Motor Neuron 1 and 2)**: Mutations in **SMN1** cause **Spinal Muscular Atrophy (SMA)**.
- **TCOF1 (Treacle Protein 1)**: Mutations in this gene lead to **Treacher Collins Syndrome**, a craniofacial disorder.

### **Associated Genetic Disorders**
Several genetic conditions and diseases are linked to mutations or deletions involving chromosome 5:
- **Cri-du-chat Syndrome**: A disorder caused by a deletion of a portion of the short arm (5p), leading to intellectual disability, delayed development, and a characteristic "cat-like" cry in infants.
- **Spinal Muscular Atrophy (SMA)**: Caused by mutations in the **SMN1** gene, leading to progressive muscle weakness.
- **Familial Adenomatous Polyposis (FAP)**: A hereditary condition caused by mutations in the **APC** gene, leading to numerous precancerous polyps in the colon and a high risk of colorectal cancer.

### **Chromosomal Abnormalities**
- **5p Deletion Syndrome (Cri-du-chat Syndrome)**: Caused by the loss of a portion of the short arm of chromosome 5.
- **5q Deletion Syndrome (5q- Syndrome)**: A condition associated with myelodysplastic syndromes (MDS), often leading to bone marrow failure.