Related diseases

The MPS Society supports 25 MPS and related diseases including the Mucolipidoses, other ‘storage diseases’ and the following conditions which are similar to Mucopolysaccharide Diseases.

Symptoms can vary greatly but all forms are characterised by a degree of neurodegeneration and cognitive impairment.

Types of diseases

Geleo Physic Dysplasia

Geleophysic Dysplasia is a very rare disease which comes under a group of conditions related to the Mucopolysaccharidoses. It is a genetic degenerative storage condition leading to premature death often in childhood.

Geleophysic Dysplasia is characterised by extremely short stature, small hands and feet, failure to thrive and accompanying physical disabilities including progressive heart disease. Growth is severely limited with shortened limbs and joint mobility is generally decreased, especially in the hands.

Aspartylglycosaminuria (AGU)

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GM-1 Gangliosidosis

GM1 Gangliosidosis is an inherited disorder that progressively destroys nerve cells (neurons) in the brain and spinal cord.

The condition has traditionally been classified into three major types based on the age at which signs and symptoms first appear.

  • Type I – Infantile
  • Type II – Late infantile and Juvenile
  • Type III – Adult/chronic

Although the three types differ in severity, their features can overlap significantly. Because of this overlap, researchers believe that GM1 Gangliosidosis represents a continuous disease spectrum instead of three distinct types.

All individuals with GM 1 Gangliosidosis have a deficiency, or absence, of the enzyme β-galactosidase which results in the accumulation of molecules that this enzyme is responsible for breaking down.

To date there are no specific treatments for GM 1 Gangliosidosis. Affected individuals receive a range of treatments to address the varying symptoms of the condition.

This condition is inherited in an autosomal recessive pattern, which means that in an affected individual, both copies of the associated gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they do not show signs and symptoms of the condition.

Lysosomal Acid Lipase Deficiency (LAL D)

LAL D is a rare genetic condition, in which sufferers are deficient in lysosomal acid lipase. This lipase plays a key role in the regulation of cholesterol and triglyceride metabolism throughout the body. Without enough LAL to process these products, they accumulate in tissue affecting mainly the liver, spleen, adrenal glands, lymph nodes and small intestine.

LAL D is a rare disease, with estimates of its occurence in children and adults ranging from 1:40,000 and 1:300,000

Children and adults commonly show various liver dysfunctions and an abnormal amount of lipids in bloods. Individuals may also present gastrointestinal symptoms and cardiovascular problems, such as coronary artery disease.

Infants will show symptoms of the disease within the first few days to the first month of life, the first of these symptoms typically including vomiting and diarrhea and growth failure.

LAL D can be diagnosed with a simple blood test.

Metachromatic Leukodystrophy

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ML I – Neuramidase Deficiency

Mucolipidosis type I (ML I), also known as Sialidosis, is a rare inherited lysosomal storage disease that has clinical and histologic findings similar to the mucopolysaccharidoses and the sphingolipidoses. Symptoms of ML I are either present at birth or develop within the first year of life. In many infants with ML I, excessive swelling throughout the body is noted at birth. These infants are often born with coarse facial features, such as a flat nasal bridge, puffy eyelids, enlargement of the gums, and excessive tongue size (macroglossia).

Many infants with ML I are also born with skeletal malformations such as hip dislocation. Infants often develop sudden involuntary muscle contractions (called myoclonus) and have red spots in their eyes (called cherry-red macules). They are often unable to coordinate voluntary movement (called ataxia). Tremors, impaired vision, and seizures also occur in children with ML I.

Tests reveal abnormal enlargement of the liver and spleen and extreme abdominal swelling. Infants with ML I generally lack muscle tone (hypotonia) and have impaired intellect that is either initially or progressively severe. Many patients suffer from failure to thrive and from recurrent respiratory infections.

ML II – I-Cell Disease

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ML III – Pseudo Hurler Polydystrophy

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Sialic Acid Storage Disease

Free sialic acid storage disorders are a group of related disorders characterised by the abnormal accumulation of sialic acid in various cells and tissues of the body. They are inherited through autosomal recessive inheritance.

There are three subtypes:

  • Infantile free sialic acid storage disease (ISSD) which is the most severe;
  • Intermediate Salla disease
  • Salla disease, the mildest form

Symptoms can vary greatly but all forms are characterised by a degree of neurodegeneration and cognitive impairment.


MPS IX (Hyaluronidase deficiency) is a condition that was first noted in 1996. It is caused by a deficiency of the enzyme, hyaluronidase. This enzyme is used in the lysosome to break down a complex string of sugars known as Glycosaminoglycans (GAGs), often referred to as mucopolysaccharides. In individuals inflicted with MPS IX, the GAG accumulates resulting in symptoms of this disorder. Symptoms include nodular soft-tissue masses located around joints, with periodic episodes of painful swelling of the masses. This pain spontaneously ends within three days. Other symptoms of this disease include a flattened nose bridge and a cleft palate. Short stature is also a noted symptom.