What Is MPS

Mucopolysaccharide (pronounced “muke – o – polly – sack -are – ide”)

The Mucopolysaccharidoses (MPSs) are rare genetic disorders in children and adults. They involve an abnormal storage of mucopolysaccharides, or long chains of sugar molecules, (also called glycosaminoglycans or GAGs) caused by the absence of a specific enzyme. Without the enzyme, the breakdown process of mucopolysaccharides is incomplete, and these glycosaminoglycans collect in the cells, blood, and connective tissues causing progressive damage to the heart, bones, joints, respiratory system and, sometimes, central nervous system. Babies affected with MPS or related diseases often show no signs of disease; however, symptoms appear and intensify as storage increases. The result is permanent, progressive cellular damage that affects the individual’s appearance, physical abilities, organ and system functioning, and, in most cases, cognitive development. The earlier the disease is diagnosed and treated the better the health outcome.


Watch this insightful documentary illustrating the world of MPS from many perspectives.

What Are the Major Characteristics of MPS?

The mucopolysaccharide storage disorders are progressive and vary widely in severity. MPS children tend to have coarse facial features and all of them have, to some degree, skeletal involvement. For most children this involves joint changes with limitation of movement. Children often have clouding of the cornea, leading to vision impairment. In all of the MPS disorders, multiple organs are involved. Enlargement of the liver and spleen and involvement of the heart and blood vessels are frequent symptoms.

Other effects of MPS may include umbilical and groin hernias, stunted growth, fluid on the brain, thickened skin, excessive hair growth, chronic runny nose, and chronic ear infections causing hearing loss. Some children will experience progressive neurological decline, depending on the type of MPS they have.

What Are the Types of MPS Syndromes?

There are many different types of MPS syndromes, each one caused by a distinct, inherited enzyme deficiency. Upon birth, a child with MPS appears normal and will seem to develop normally for the first year or more, depending on the type of MPS they have. The first signs can vary and are evident at different ages in affected children. Symptoms that usually prompt medical attention include frequent ear infections, runny noses, and colds. Different types of MPS will persent different characteristics.

Learn more about the different types of MPS >