Mucopolysaccharide diseases Dr Trisha Macnair An enzyme deficiency leads to a build up of molecules in connective tissues.

In this article

What are mucopolysaccharide diseases (MPS)? Symptoms

Causes and risk factors Treatment and recovery

Advice and support

MPS, also known as lysosomal storage diseases, are rare, life-threatening, progressive metabolic conditions each caused by a shortage of a particular enzyme.

The enzyme deficiency that results from mucopolysaccharide diseases means the body can't break down (metabolise) certain molecules called GAGs (glycosaminoglycans).

GAGs are structural molecules that are integral to connective tissues such as cartilage. They accumulate in cells within tiny structures called lysosomes. This leads to dysfunction the cells, resulting in dysfunction of tissues and organs.

There are many different types of MPS including: Hurler; Hunter; Sanfillipo; Morquio; Maroteaus-Lamy and Sly.

Patients with MPS appear normal at birth and usually present with developmental delay in the first year of life. The different types have slight variation in symptoms, which include problems with their eyes, skin, heart, bones and mental retardation.

Hurler syndrome (MPS 1) typifies MPS. It is the most severe form, progresses quickly and normally results in death by the age of 10. The clinical features of Hurler syndrome are:

• Coarse faces, large tongues, male-pattern hairiness and corneal clouding
• Airway problems and glue ear
• Skeletal deformities
• Cardiomyopathy (a problem with the heart muscle)
• Large liver and spleen
• Hernias
• Stiff joins
• Hearing loss
• Developmental delay and retardation

MPS is an inherited disease. The majority of types are inherited by autosomal recessive transmission. That means that if both of your parents are carriers, you have a one if four chance of having the disease.

Although there's no cure, enzyme replacement therapy (ERT) and bone marrow transplantation are available to treat some forms of MPS. People with MPS will need supportive care, including physiotherapy and attention to breathing problems.

Prenatal diagnosis is available using CVS (chorionic villus sampling) at about 11 weeks or amniocentesis at around 12-14 weeks.

The Society for Mucopolysaccharide Diseases
Tel: 0845 389 9901
Email: mps@mpssociety.co.uk
Website: www.mpssociety.co.uk

This article was last medically reviewed by Dr Orlena Kerek in February 2009