The protein affected in Wilson's disease is copper-transporting ATPase 2.
Understanding Copper-Transporting ATPase 2 and Wilson's Disease
Wilson's disease is a genetic disorder characterized by the body's inability to properly remove excess copper. This malfunction stems from defects in the ATP7B gene, which provides the blueprint for the copper-transporting ATPase 2 protein. This protein is primarily located in the liver and plays a crucial role in copper metabolism. Specifically, it performs two essential functions:
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Attaching Copper to Ceruloplasmin: Copper-transporting ATPase 2 attaches copper to ceruloplasmin, a protein that transports copper in the bloodstream to other tissues. This process is essential for copper's safe and efficient delivery throughout the body.
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Excreting Excess Copper in Bile: This protein also facilitates the excretion of excess copper from the liver into bile, which is then eliminated from the body in the stool.
How Defects in Copper-Transporting ATPase 2 Lead to Wilson's Disease
When the ATP7B gene contains mutations, the copper-transporting ATPase 2 protein is either non-functional or produced in insufficient quantities. This impairment disrupts both of its critical functions, leading to:
- Reduced Ceruloplasmin Production: Less copper is attached to ceruloplasmin, resulting in lower levels of ceruloplasmin in the blood.
- Impaired Copper Excretion: Excess copper accumulates in the liver because the protein is unable to effectively remove it.
This buildup of copper eventually damages the liver and other organs, including the brain, eyes, and kidneys, leading to the characteristic symptoms of Wilson's disease. Early diagnosis and treatment, which involves copper-chelating agents and zinc therapy, are crucial to prevent irreversible organ damage.
