about MPS

MPS I (Hurler, Hurler-Scheie, Scheie syndrome)

Mucopolysaccharidosis I (MPS I) is a lysosomal storage disorder that damages numerous organs, tissues, and body systems. It is caused by a mutation in the gene that makes an enzyme called alpha-L-iduronidase resulting in low-levels of enzyme or none at all. The different classifications of the disease relate to its severity (Scheie being mild, Hurler-Scheie being moderate, and Hurler Syndrome being the severe end of the spectrum). This enzyme is needed to break down substances called glycosaminoglycans (GAGs), which are by-products of regular chemical reactions in the body’s cells. As GAGs build up they tend to damage cells, tissues, and organs. It affects approximately 1 in every 100,000 male and female births.

 

MPS II (Hunter Syndrome)

Mucopolysaccharidosis II (MPS II) is a lysosomal storage disorder that damages a wide range of organs, tissues, and body systems. There are two classification of MPS II, neuronopathic and non-neuronopathic. It is caused by a deficiency in iduronate sulfatase, which is essential to breaking down the glycosaminoglycans (GAGs) dermatan and heparan sulphate. Symptoms vary, but include respiratory infections, hearing impairment, liver and spleen enlargement, inguinal and abdominal hernias, joint stiffness and multiplex dysplasia, compression of tendons in the wrist (carpal tunnel syndrome), and joint stiffness. It almost entirely affects males at a rate of 1 in every 170,000 births.

 

MPS III (Sanfilippo Syndrome)

Mucopolysaccharidosis III (MPS III) is a lysosomal storage disorder that damages a wide range of organs, tissues, and body systems. There are four types of MPS III (A,B,C,D).  These are classified by different missing enzymes that are needed to break down substances called glycosaminoglycans (GAGs), which are a by-product of regular chemical reactions in the body’s cells. In MPS III developmental delay is usually evident from 2-5 years old, and mental and motor development will peak at around 6-8 years of age. It affects boys and girls equally at a rate of approximately 1 in every 200,000 births worldwide.

 

MPS IV (Morquio Syndrome)

Mucopolysaccharidosis IV (MPS IV) is a lysosomal storage disorder that damages a wide range of organs, tissues, and body systems. There are two types of MPS IV (A, B). MPS IVA occurs because of a deficiency of the enzyme N-acetyl-galactosamine-6-sulfatase (GALNS) and MPS IVB occurs due to a deficiency of beta-galactosidase. Both lead to a accumulation of keratan sulfate in the body’s cells. Symptoms of MPS IV tend to include physical deformities of the spine, neck, knees, feet, hips, breasts, face, and lower-legs, as well as growth retardation. MPS IVA accounts for 95% of diagnosis. MPS IV (both types) affects boys and girls equally at a rate of 1 in every 40,000 to 1 in every 100,000 births worldwide.

 

MPS VI (Maroteaux-Lamy Syndrome)
Mucopolysaccharidosis VI (MPS VI) is a lysosomal storage disorder that damages a wide range of organs, tissues, and body systems. It is caused by a deficiency or absence in arylsulfatase B, which leads to the accumulation of glycosaminoglycans (GAGs). Symptoms can vary dramatically, but common are corneal clouding, joint deformities, skeletal malformations, enlarged liver and/or spleen, coarse facial features, and hearing loss. Symptoms come at various stages of life depending on severity of the disease. Numbers on prevalence vary wildly because of the milder forms of the disease and go from 1 in every 40,000 to 1 in every 1,500,000 male and female births worldwide.