Charcot-Marie-Tooth disease is caused by duplication of the peripheral myelin protein-22 (PMP22) gene on which chromosome?

The correct answer is chromosome 17.

Key Points

• Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders, affecting the peripheral nerves.
• It is specifically caused by the duplication of the PMP22 gene located on chromosome 17.
• The disease leads to the progressive loss of muscle tissue and touch sensation, primarily in the feet, legs, hands, and arms.
• CMT can be classified into several types, with CMT1A being the most common form linked to the duplication of PMP22.
• Diagnosis often involves genetic testing to identify the duplication of the PMP22 gene on chromosome 17.

Additional Information

• PMP22 Gene:
  • The Peripheral Myelin Protein 22 (PMP22) gene plays a crucial role in the structure and function of myelin, the protective sheath around nerves.
  • Overexpression of PMP22 due to gene duplication disrupts the production of normal myelin, leading to nerve degeneration.
• Symptoms of CMT:
  • Common symptoms include muscle weakness, decreased muscle size, decreased sensation in extremities, foot deformities, and difficulty walking.
  • Symptoms typically appear in adolescence or early adulthood.
• Types of CMT:
  • CMT1: Caused by abnormalities in myelin.
  • CMT2: Caused by abnormalities in the axon of the peripheral nerve cell.
  • CMTX: X-linked inheritance pattern, often affecting males more severely.
• Treatment and Management:
  • There is currently no cure for CMT; treatment focuses on managing symptoms.Physical therapy, occupational therapy, and orthopedic devices can help maintain mobility and function.
  • Regular monitoring and supportive care are essential for improving the quality of life for individuals with CMT.