mucopolysaccharidosis

What is Mucopolysaccharidosis?

Mucopolysaccharidosis (MPS) refers to a group of rare genetic disorders caused by defects in enzymes required for the breakdown of glycosaminoglycans (GAGs), also known as mucopolysaccharides. These sugars are found throughout the body and play a crucial role in various cellular processes.

Causes and Symptoms

The main function of lysosomes is to break down and recycle waste materials. In MPS, enzymes that normally break down or degrade complex molecules into simpler ones are deficient or absent. As a result, these sugars accumulate in cells, blood, and connective tissue, leading to a variety of health problems.

Types of Mucopolysaccharidosis

There are several types of MPS, including:

• Hurler syndrome (MPS 1-H): the most severe form of MPS
• Hunter syndrome (MPS II): affects many different parts of the body
• Sanfilippo syndrome (MPS III): a rare genetic condition causing fatal brain damage
• Morquio syndrome (MPS IVA): characterized by an abnormal build-up of toxic materials

Inheritance and Prevalence

MPS has an autosomal recessive pattern of inheritance, meaning that a person must inherit two copies of the mutated gene (one from each parent) to develop the condition. It is estimated that 1 in 25,000 babies born in the United States will have some form of MPS.

Clinical Description

The symptoms and severity of MPS vary depending on the type and individual case. Most individuals experience a period of normal development followed by a decline in physical and/or mental function. In severe cases, such as Hurler syndrome, symptoms become evident at six months to two years of age.

References:

• [1] 50. N o r t h o v e r H, C o w i e R A, W r a i t h J E. Mucopolysaccharidosis type IVA (Morquio syndrome): a review of the literature.
• [2] Approximately 1 in 100,000 newborns will experience severe MPS type I, while approximately 1 in 500,000 newborns will experience attenuated MPS type I.
• [3] Mucopolysaccharidosis refers to a group of inherited conditions in which the body is unable to properly breakdown mucopolysaccharides (long chains of sugar molecules that are found throughout the body).

Mucopolysaccharidosis (MPS) is a group of rare genetic disorders that affect the body's ability to break down and recycle sugar molecules. The signs and symptoms of MPS can vary depending on the type, but here are some common ones:

Short stature: Individuals with MPS are often short-statured, which means they may not reach their full height potential [2]. Stiff joints: Stiffness in the hands and other joints is a common symptom of MPS [2]. Corneal clouding: Some types of MPS can cause cloudy corneas, which can affect vision [3]. Progressive intellectual delay: Children with Hurler syndrome (MPS I) may experience progressive intellectual decline [4]. Abnormal bones in the spine: Abnormal bone formation in the spine is a symptom of some types of MPS [5]. Claw hand: Inability to fully open the fingers, also known as claw hand, can be a sign of MPS [6]. Cloudy corneas: Cloudy corneas are a common symptom of MPS II and other types [7]. Enlarged head (macrocephaly): Some individuals with MPS VI may have an enlarged head [8]. Build-up of fluid in the brain (hydrocephalus): Hydrocephalus is a rare but serious complication of MPS VI [9].

It's worth noting that these symptoms can vary in severity and may not be present in all cases. Additionally, some types of MPS may have unique symptoms not listed here.

References:

[2] - Individuals with mucopolysaccharidoses are short-statured and have stiff joints, especially in the hands. [3] - Some types of the disorders may also cause corneal clouding, and progressive intellectual delay is seen in children with Hurler syndrome. [4] - Apr 24, 2023 — Symptoms · Abnormal bones in the spine · Inability to fully open the fingers (claw hand) · Cloudy corneas · Deafness · Halted growth · Heart valve ... [5] - Children with MPS 1 often have no signs or symptoms of the condition at birth. However, babies with severe MPS 1 generally begin to show symptoms within the first year of life. [6] - Aug 17, 2022 — Physical characteristics · Short stature. · Bones forming incorrectly (dysostosis). · Rounding curve of your child's upper back (thoracic-lumbar ... [7] - What are the symptoms of MPS VI? · An enlarged head (macrocephaly) · Build-up of fluid in the brain (hydrocephalus) · An enlarged tongue (macroglossia) · Coarse ... [8] - Apr 22, 2019 — Individuals with severe MPS I have onset of symptoms in early infancy with evidence of early progressive intellectual decline and when ... [9] - Nov 7, 2022 — Early signs and symptoms of MPS. Many symptoms are shared among the different types of MPS. However, there is a wide range of symptom severity. ...

Treatment Options for Mucopolysaccharidosis

Mucopolysaccharidosis (MPS) is a group of rare genetic disorders caused by the deficiency of enzymes needed to break down sugar molecules. While there is no cure for MPS, various treatment options are available to manage its symptoms and improve quality of life.

Enzyme Replacement Therapy (ERT)

ERT involves replacing the deficient enzyme with a functional one to help break down accumulated sugar molecules. Several ERTs have been approved by the FDA for different types of MPS:

• Aldurazyme (laronidase): Approved for the treatment of Hurler syndrome (MPS I) [6][8]
• Elaprase (idursulfase): Approved for the treatment of Hunter syndrome (MPS II) [4]
• Elosulfase alfa: Approved for the treatment of Morquio A syndrome (MPS IVA) [3]

Other Treatment Options

In addition to ERT, other treatment options are available for MPS:

• Bone marrow transplant: May be considered for Hurler syndrome (MPS I) patients [10]
• Osteotomies and guided growth: Can help correct bone misalignment in patients with MPS-related orthopedic conditions [10]

Emerging Therapies

Research is ongoing to develop new treatments for MPS. For example:

• Genistein: A soy-derived isoflavone being studied as a potential treatment for systemic manifestations of MPS [15]
• ArmaGen AGT-181: An investigational enzyme replacement therapy for the treatment of neurological complications in patients with Hurler syndrome [9]

References

[1] "Mucopolysaccharidoses: Clinical features and diagnosis" (See separate article) [2] "Mucopolysaccharidoses: Complications" (See separate article) [3] Context result 3 [4] Context result 4 [5] Context result 5 [6] Context result 6 [7] Context result 7 [8] Context result 8 [9] Context result 9 [10] Context result 10