Matthew Ellinwood, DMV, PhD, Chief Scientific Officer at the MPS Society, provides an overview of the mucopolysaccharidoses (MPSs) and mucolipidoses (MLs). 

The MPSs are a group of inherited metabolic diseases caused by the absence or malfunctioning of certain enzymes needed to break down glycosaminoglycans, which are long chains of sugar carbohydrates that help build bone, cartilage, tendons, corneas, skin, and connective tissue. 

People with a mucopolysaccharidosis either do not produce enough of one of the 11 enzymes required to break down these sugar chains into proteins and simpler molecules or they produce enzymes that do not work properly. Over time, these glycosaminoglycans collect in the cells, blood, and connective tissues. 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.

As Dr. Ellinwood explains, most MPSs are rare genetic conditions that are often difficult to diagnose before permanent damage has already occurred. Further, many MPSs have approved treatments (i.e., MPS I, MPS II, MPS IV, MPS VI, MPS VII) and as such, there is a need to make them part of newborn screening. 

Although treatments are currently available, all of them are enzyme replacement therapies that cannot cross the blood brain barrier. Therefore, there is significant clinical research underway to provide methods to attenuate the cognitive and behaviour symptoms that afflict many of these rare diseases. These include novel methods to infuse enzyme replacement therapies as well as gene therapies that currently being investigated. 

The MPS Society also advocates for  mucolipidosis (ML II, ML III), another set of lysosomal diseases that are similar to some of the MPSs (i.e., MPS I). 

To learn more about various  MPSs, visit our learning center at