What is Morquio syndrome?
Morquio syndrome, also known as MPS IV belongs to a broad category of diseases which is termed as mucopolysaccharidosis (MPS). Morquio syndrome is genetic disease. The disease may not be visible at birth. This syndrome mainly affects the skeleton and is progressive with symptoms getting worse as a child grows.
Morquio syndrome is genetic disease. The disease may not be visible at birth. This syndrome mainly affects the skeleton and is progressive with symptoms getting worse as a child grows.
What is the prevalence of this disease?
The exact prevalence of MPS IV is unknown, although it is estimated to occur in 1 in 200,000 to 300,000 individuals.
What are the types and causes of Morquio Syndrome?
There are 2 forms of Morquio syndrome: Type A and Type B.
· People having Type A syndrome do not have a substance (enzyme) called galactosamine-6-sulfatase in their body.
· People having Type B syndrome cannot synthesize enough of an enzyme called beta-galactosidase. Type B syndrome behaves similar to Type A, except for the genetic defect (in a different gene).
Morquio syndrome is an inherited genetic condition. If both the parents carry mutations in a gene related to this condition, each of their children has a 25% (1 in 4) chance of developing the disease. This is an autosomal recessive trait.
Morquio A Syndrome
What Is Morquio A syndrome?
Morquio A syndrome is a genetic condition where the body doesn’t produce enough of the enzyme N-acetylgalactosamine-6 sulfatase (GALNS). Hence the body cannot break down the molecule glycosaminoglycans (GAGs) which then accumulate in the bones, tissues and organs. GAGs build up within the cells particularly in the lysosomes which are small compartments in the cell responsible for breakdown and recycling of various molecules. Hence this condition is often referred to as Lysosomal Storage Disorder.
What are the signs and symptoms of Morquio Syndrome?
Symptoms usually occur between ages 1 and 3. Some of the prominent symptoms include:
What genes are related to mucopolysaccharidosis type IVa?
Mutations in the galactosamine (N-acetyl)-6-sulfatase (GALNS) gene cause MPS IVA. This gene gives instructions for producing enzymes responsible for breakdown of large sugar molecules called glycosaminoglycans (GAGs).
What are the tests and diagnosis available for this disorder?
There are two kinds of clinical tests available for the Morquio A patients.
1) Enzyme test will measure the levels of the enzyme N-acetylgalactosamine-6 sulfatase (GALNS) in blood.
2) Molecular Analysis of galactosamine (N-acetyl)-6-sulfatase (GALNS) gene can be performed and is clinically available.
Besides the above tests, prenatal diagnosis is possible and the test is offered to couples with a previous child with Morquio syndrome (or carrier couple).
What kind of treatment can be provided to people suffering from this disorder?
Elosulfase alfa or Vimizim™ medicine was approved by the US-Food and Drug Administration in February 2014 for the treatment of Morquio A syndrome. The medicine is given intravenously (IV). The treatment can be modified based on the symptoms. Talk to your physician for more information on possible options for treatment. They also might require some treatment from orthopaedic surgeons.
Which are the different support groups or organizations to contact for further information ?
The Department of Health Research and Indian Council of Medical Research have constituted a National Task Force to perform a multicentric collaborative study at different research institutes across the country. Further information can be found at http://www.icmrmetbionetindia.org/task-force-disoredrs.php
What are the best possible ways to prevent and control the condition?
Genetic counselling is offered and recommended for couples with a known family history of Morquio A syndrome. Counselling can also help the couple who are planning to have children understand the genetic risk, carrier status and the importance of performing prenatal testing before pregnancy. Counselling can also be provided to affected families. This can help the affected families understand the condition and provide possible treatments.
When to contact a Medical Professional?
The physician can be contacted if symptoms of Morquio A syndrome occur.
What are the alternative names for this disorder?
Mucopolysaccharidosis type IVA; Galactosamine-6-sulfatase deficiency
Available from: http://www.ncbi.nlm.nih.gov/books/NBK148668/
|PATIENT INFORMATION SHEETS (PIS), CONSENT FORMS, PATIENT DATA RECORD FORMS AND SOPS FOR MORQUIO SYNDROME|
Dr Girisha KM
Kasturba Medical College, Manipal