“Please, tell me more about mps.”

• “muco” refers to the thick jelly-like consistency of the molecules

• “poly” means many

• “saccharide” is a general term for a sugar molecule

Mucopolysaccharidoses are a group of inherited metabolic diseases caused by the absence or malfunctioning of certain enzymes needed to break down molecules called glycosaminoglycans - long chains of sugar carbohydrates in each of our cells that help build bone, cartilage, tendons, corneas, skin, and connective tissue. Glycosaminoglycans (formerly called mucopolysaccharides) are also found in the fluid that lubricates our joints.

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. 

It is estimated that one in every 25,000 babies born in the United States will have some form of the mucopolysaccharidoses. They are autosomal recessive disorders, meaning that only individuals inheriting the defective gene from both parents are affected. (The exception is MPS II, or Hunter syndrome, in which the mother alone passes along the defective gene to a son.) When both people in a couple have the defective gene, each pregnancy carries with it a one in four chance that the child will be affected. The parents and siblings of an affected child may have no sign of the disorder. Unaffected siblings and select relatives of a child with one of the mucopolysaccharidoses may carry the recessive gene and could pass it to their own children. 

In general, the following factors may increase the chance of getting or passing on a genetic disease:

• A family history of a genetic disease.

• Parents who are closely related or part of a distinct ethnic or geographic circle.

• Parents who do not show disease symptoms but carry a disease gene.

The mucopolysaccharidoses are classified as lysosomal storage diseases. These are conditions in which large numbers of molecules that are normally broken down or degraded into smaller pieces by intracellular units called lysosomes accumulate in harmful amounts in the body's cells and tissues, particularly in the lysosomes.

There are 7 different types of MPS:

MPS I (Hurler syndrome),
MPS II (Hunter syndrome),
MPS III (Sanfilippo syndrome),
MPS IV (Morquio syndrome),
MPS VI (Maroteaux-Lamy syndrome),
MPS VII (Sly syndrome)

“Please, Tell me more about sanfilippo syndrome.”

Sanfilippo syndrome (or MPSIII) is a rare genetic mucopolysaccharide disease. You may also hear it to be known as ‘the childhood alzheimer’s disease.’ Mucopolysaccharides are long chains of sugar molecules, which are used in building connective tissues. When the body is finished using these molecules, it breaks them down, with enzymes, and disposes of them. Children with Sanfilippo syndrome are missing or are deficient in the enzyme to break down the molecules. So instead, their body stores these molecules in the cells. As these ‘trash cells’ build up over time and are unable to be broken down and disposed of, this storage causes progressive damage.

Sanfilippo Type A is the most common. It is considered the most severe type with earlier death than the others. These children are deficient in the enzyme Heparan N-sulfatase.

Sanfilippo Type B is the second most common. This is the result of a deficiency in N-acetyl-alpha-D-glucosaminidase.

Sanfilippo Type C is caused by a deficiency in Acetyl-CoAlpha-glucosaminide acetyltransferase.

Sanfilippo Type D is caused by a deficiency in N-acetylglucosamine 6-sulfatase.

Sanfilippo syndrome was first described in 1963 by Dr. Sylvester Sanfilippo and is considered rare, with an occurrence of 1 in every 70,000 births. It is an autosomal recessive hereditary disorder, which means, both parents must be carriers in order for the child to be affected. There is a one in four chance of having a child born with Sanfilippo syndrome. There is a two in three chance that unaffected children will be carriers.

The disease affects each person differently, and its progress will be much faster in some individuals than in others. Sanfilippo syndrome is a progressive disorder, meaning that at birth the children appear typical and do not show signs of the disorder. As the disease progresses the children degenerate, losing the ability to speak, walk, eat and eventually lose their lives. Babies may show little sign of the disease, but as cells sustain damage, symptoms start to appear.

______________________________

In the first stage of the disorder it is noticed that the child lags behind and develops behavioral issues. Symptoms often appear after age 1, and learning abilities begin to slow between ages 2 and 6. Normal growth continues during the first few years, but will begin to slow, and final height is below average.

In the second stage, the child may become extremely active, restless, and often have very difficult behavior. Some children have sleep disturbances. Many like to chew on their hands and clothing. Language and understanding will gradually become lost.

In the third stage the child begins to slow down. They have difficulty walking, falling often eventually losing the ability to walk altogether. The stages of overall health will start to decline here as well.

The current life expectancy is 10-20 years of age.

Other symptoms that most children will have include:

• Behavioral problems: hyperactivity or aggressive

• Speech/developmental delays

• Coarse/heavy facial features

• Diarrhea/vomiting when not showing any sign of being sick

• Full lips

• Dementia

• Sleep difficulties

• Stiff joints that may not extend fully

• Walking problems

• Seizures

• Excessive drooling

• Eating, chewing and swallowing issues

• Upper respiratory infections

• Hearing loss

• Severe intellectual impairment

• Partial paralysis

• Vision loss

https://mpssociety.org/learn/diseases/mps-iii/
https://teamsanfilippo.org/what-is-sanfilippo-syndrome
https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Mucopolysaccharidoses-Fact-Sheet

HOW CAN YOU HELP US ADVOCATE?

• Wear purple for Sanfilippo! (MPS Awareness Day is May 15th)

• Wear purple to celebrate Owen’s Birthday! We are blessed to have him with us for another year! (June 18th)

• Wear your Owen bracelet or shirts to celebrate him and so many others on Rare Disease Day! (February 28th)

• Attend any upcoming events to show your support

• Say hello to Owen! Just remember to keep your conversation at a 3 year old level :)

• Purchase anything from our online store as all proceeds will be a huge help in so many ways.

• Donate with us into treatments that are available and research.

• Tell someone you know about Owen’s Story! Sharing is a free and simple way to show that you care.

• Keep up to date with our family blog or Owen’s Facebook page and all of Owen’s upcoming appointments.