About mps disorder iii

What is mps disorder iii?

The Mucopolysaccharidoses (MPS Disorders) are a group of rare genetic disorders caused by the deficiency of one of the lysosomal enzymes, resulting in an inability to metabolize complex carbohydrates (mucopolysaccharides) into simpler molecules. High concentrations of mucopolysaccharides in the cells of the central nervous system, including the brain, cause the neurological and developmental deficits that accompany these disorders.

Mucopolysaccharides are rather thick jelly-like ("muco") compounds made of long chains ("poly") of sugar-like (saccharides) molecules used to make connective tissues in the body.

Lysosomal enzymes are found in the lysosome, a very small membrane-contained body (organelle) found in the cytoplasm of most cells. The lysosome is often called the "waste disposal plant" of the cell. The accumulation of these large, undegraded mucopolysaccharides in the cells of the body is the cause of a number of physical symptoms and abnormalities.

MPS-III (Sanfilippo Syndrome) is one of seven MPS Disorders. It is an inborn error of metabolism that is transmitted as an autosomal recessive genetic disorder. MPS-lll has been subdivided into four types: MPS-III Type A, MPS-III Type B, MPS-III Type C, and MPS-III Type D. All types are associated with some degree of mental deterioration, but the severity depends on the particular type of MPS-lll. Several physical defects may be present, and the severity of these defects varies with the type of MPS-III. In the case of each type of MPS-III, abnormal amounts of a specific, chemically complex molecule is excreted in the urine. The excreted chemical is the same for each of the four types of MPS-III, since the defective gene involves a different step, and thus a different enzyme, in the deconstruction of the same mucopolysaccharide. By testing for one or another of these enzymes, the variant type may be readily identified.

What are the symptoms for mps disorder iii?

Respiratory and ear in symptom was found in the mps disorder iii condition

Sanfilippo syndrome often goes unnoticed during the first months — or even years — of a child's life. Even though there may be some signs at an early age, doctors usually confuse them for other conditions.

Most of the Sanfilippo syndrome symptoms start at the age between 1 and 6 years — they include developmental delay, trouble sleeping, and frequent infections.

Common symptoms seen at the first Sanfilippo syndrome stage include:

  • Behavioral issues
  • Speech and development delays
  • Persistent diarrhea
  • Frequent infections, especially in the ear and throat
  • Trouble sleeping

As the disorder progresses, a child with Sanfilippo syndrome will start displaying even more severe symptoms. Often, kids at this stage need to use a feeding tube because they lose their motor skills by then. During this stage, sleep and behavioral issues become more pronounced.

The second stage of Sanfilippo syndrome is marked by these symptoms:

  • Extreme restlessness
  • Gradual loss of language
  • Hyperactivity
  • Hearing loss
  • Seizures
  • Progressive intellectual disability

In the final stage, an affected child will lose their motor skills, which will slow them down considerably. Movement disorders and loss of walking ability are common, and at this stage, most children aren’t able to speak or eat anything. Children at this stage will usually show:

  • Movement disorders
  • Contractures of hands and fingers
  • Frequent falling
  • Arthritis
  • Visual impairment

What are the causes for mps disorder iii?

Mutations in the GNS, HGSNAT, NAGLU, and SGSH genes cause MPS III. These genes provide instructions for making enzymes involved in the breakdown of large sugar molecules called glycosaminoglycans (GAGs). GAGs were originally called mucopolysaccharides, which is where this condition gets its name. The GNS, HGSNAT, NAGLU, and SGSH enzymes are involved in the step-wise breakdown of a subset of GAGs called heparan sulfate.

MPS IIIA is caused by mutations in the SGSH gene, and MPS IIIB is caused by NAGLU gene mutations. Mutations in the HGSNAT gene result in MPS IIIC, and GNS gene mutations cause MPS IIID. Mutations in these genes reduce or eliminate enzyme function. A lack of any one of these enzymes disrupts the breakdown of heparan sulfate. As a result, partially broken down heparan sulfate accumulates within cells, specifically inside the lysosomes. Lysosomes are compartments in the cell that digest and recycle different types of molecules. Conditions such as MPS III that cause molecules to build up inside the lysosomes are called lysosomal storage disorders. Researchers believe that the accumulation of GAGs interferes with the functions of other proteins inside the lysosomes and disrupts the normal functions of cells. It is unknown why the buildup of heparan sulfate mostly affects the central nervous system in MPS III.

What are the treatments for mps disorder iii?

There's no cure for Sanfilippo syndrome. But several symptom-specific treatments can be prescribed to elevate the affected child’s quality of life. 

There are a few possible therapeutic avenues under research that may help treat Sanfilippo syndrome in the future. One such avenue is enzyme-replacement therapy, where the child is injected with an infusion of the enzyme they can’t produce — which allows them to metabolize heparan sulfate until the next injection.

What are the risk factors for mps disorder iii?

Mucopolysaccharidosis Disorders are a group of rare genetic conditions caused due to deficiency of one of the lysosomal enzymes. MPS Type-III is one of seven Mucopolysaccharidosis Disorders. It is a result of an inborn metabolism error transmitted as an autosomal recessive genetic condition. An abnormal quantity of a certain chemically complex molecule excreted in the urine is one of the most prevalent symptoms of MPS disorder III (MPS-III).

Risk Factors of MPS-III
More commonly found in Southern Europe

If both parents are carriers:
1. 1 in 4 risk of giving birth to an affected child
2. 1 in 2 chance of a child inheriting a single copy of the defective gene, and thus, resulting in a carrier
3. 1 in 4 chances of the child will neither be a carrier nor affected. This particular risk is the same in both males and females.

Behavioral problems such as hyperactivity and irritability may become obvious earlier,Coarse hair,Excess hair growth (hirsutism),Slightly coarse facial features,Sleeping problems,Mildly enlarged liver and/or spleen,Speech delay,Respiratory and ear infections,Diarrhea,Hernias,Seizures,A wobbly and erratic walk
Fatal brain damage,Sanfilippo syndrome,Childhood dementia
Symptomatic treatments

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