Why is there decreased cerruloplasmin in Wilson disease
More copper will bind with ceruloplasmin hence decreasing its level
The defect in Wilson’s disease is to ATP7B. This protein does two things:
Couples copper to ceruloplasmin (the main form of circulating copper). Ceruloplasmin without copper is not ceruloplasmin so without the ATP7B protein to do this, there is no ceruloplasmin.
Eliminated excess copper by facilitating its excretion. Copper builds up as a result.