Mucopolysaccharides are long chains of sugar molecules found throughout the body, usually in mucus and fluid around the joints. They are more ordinarily known as glycosaminoglycans. When the body cannot break down mucopolysaccharides, a condition called mucopolysaccharidoses (MPS) happens. MPS refers to a group of heritable disorders of metabolism. Individuals with MPS do not have any, or enough, of a substance (enzyme) required to break down the sugar molecule chains.
Happenings Due to MPS Disorder
MPS disorder leads to several similar symptoms like multiple organ involvement, distinctive “coarse” facial expression, and skeleton abnormalities, particularly involving joint issues. Other prominent problems include short stature, heart abnormalities, respiratory irregularities, liver and spleen enlargement (hepatosplenomegaly), and/or neurologic abnormalities. The severity of MPS disorders widely varies from person to person. People suffering from identical forms of MPS and those belonging to the same family may also experience different levels of severity.
In most cases of MPS, affected infants seem normal at birth, and symptoms become apparent around the age of 1 or 2; however, in MPS VII, around 400th of pregnancies with an affected baby are difficult by a condition known as non-immune hydrops fetalis that will be detected on routine ultrasound examination. Initial symptoms might embrace frequent colds, runny nose, infections, growth delays, or gentle developmental delays. Mild types of these disorders might not become apparent till childhood or adolescence. In most cases, the mucopolysaccharidoses are observed to be chronic and progressive disorders. Also, relying on the kind of MPS and severity, affected people might experience a decline in physical and mental performance, typically leading to critical complications.
Symptoms could also be mild, moderate or severe based on MPS. All people do not present with retardation or developmental delays. There is a typical cluster of symptoms occurring across clinical varieties and subtypes of MPS, such as facial features like flat nasal bridge and thick lips, short story, dysplasia or abnormal bone size or shape, hearing loss, corneal clouding and vision impairment, hydrocephalus (fluid in the brain), developmental delays and mental retardation, enlarged organs like heart, liver and spleen, respiratory issues, and heart diseases.
Causes
- Deficiency or malfunction of a specific lysosomal enzyme necessary to break down dermatan sulphate, heparan sulphate, or keratan sulphate results in MPS disorders, either alone or together. Failure to break down these mucopolysaccharides results in their accumulation in cells, tissues and organs throughout the body.
Diagnosis
Diagnosis of mucopolysaccharidoses is based on medical history, physical examination and clinical investigations.
Urine tests indicate the presence of excess mucopolysaccharides. Clinical evaluation, identification of characteristic findings such as skeletal malformations, coarse facial features, hepatosplenomegaly and a variety of specialised tests, including urine analysis, help detect excessive levels of mucopolysaccharides. Tests known as enzyme assays may be performed to detect deficient levels of lysosomal enzymes in the body’s cells.
Newborn screening for MPS I has recently been approved for inclusion in the Recommended Universal Screening Panel, although each state decides independently when or if it will be added to its newborn screening panel MPS II is currently being screened in Illinois. After an abnormal newborn screening result, it would be necessary to follow up with a definitive diagnosis by enzyme assay.
Prenatal diagnosis is possible through the use of amniocentesis and chorionic villus sampling. A fluid sample surrounding the developing foetus during amniocentesis is removed and studied. During CVS, tissue samples are removed from a portion of the placenta, and DNA studies may be performed, primarily in families with a previously affected child, and the abnormal gene mutations are known.
Conclusion
Mucopolysaccharidosis (MPS) is a group of genetic metabolic disorders occurring due to the malfunctioning or absence of specific enzymes required to process molecules called glycosaminoglycans. Mucopolysaccharides are long chains of sugar molecules found throughout the body, often in mucus and in the fluid around the joints. They are more commonly called glycosaminoglycans. The mucopolysaccharidoses (MPS) are a group of inherited lysosomal storage diseases. Lysosomes function as the primary digestive unit within cells. Enzymes within lysosomes digest or break down particular nutrients, such as carbohydrates and fats. In people suffering from MPS, the deficiency or malfunction of specific lysosomal enzymes causes abnormal accumulation of certain complex carbohydrates (mucopolysaccharides or glycosaminoglycans) in eyes, ears, arteries, skin, skeleton, joints, and teeth. These accumulations may also be found in the respiratory system, liver, spleen, central nervous system, blood, and bone marrow. Eventually, this accumulation leads to progressive damage of tissues, cells, thereby various body organ systems. There are several different types and subtypes of mucopolysaccharidosis. These disorders, with one exception, are inherited as autosomal recessive traits.