In the course of normal life there is a continuous recycling process of building new materials and breaking down old ones ready for disposal. This activity takes place in a special part of the body’s cells called the lysosome. This process requires a series of biochemical tools called enzymes. Mucolipin-1, an enzyme, plays a role in the transport of fats (lipids) and proteins.
In children with ML IV levels of mucolipin-1 are low or the absent and normal transport of fats and proteins is affected. Mucolipin-1 appears to be important for the development and maintenance of the brain and retina. Babies may show little sign of the disease, but symptoms start to appear as more and more cells become damaged by the accumulation of fats and proteins which have not been transported.