Morquio syndrome
Mucopolysaccharidosis type IVA; Galactosamine-6-sulfatase deficiency; Mucopolysaccharidosis type IVB; Beta galactosidase deficiency; MPS IV
Morquio syndrome is a disease of metabolism in which the body is missing or does not have enough of a substance needed to break down long chains of sugar molecules. These chains of molecules are called glycosaminoglycans (formerly called mucopolysaccharides).
The syndrome belongs to a group of diseases called mucopolysaccharidoses (MPS). Specifically, it is known as MPS IV.
See also:
-
MPS I H (Hurler syndrome)
MPS I H (Hurler syndrome)
Hurler syndrome is a rare disease of metabolism in which a person cannot break down long chains of sugar molecules called glycosaminoglycans (formerl...
-
MPS II, Hunter syndrome
MPS II, Hunter syndrome
Hunter syndrome is a disease in which long chains of sugar molecules (glycosaminoglycans, formerly called mucopolysaccharides) are not broken down co...
-
MPS III (Sanfilippo syndrome)
MPS III (Sanfilippo syndrome)
Sanfilippo syndrome is metabolism disorder in which the body cannot properly break down long chains of sugar molecules. These chains of molecules ar...
-
MPS I S (Scheie syndrome)
MPS I S (Scheie syndrome)
Scheie syndrome is metabolism disease in which the body cannot properly break down long chains of sugar molecules called glycosaminoglycans (formerly...
Causes
Morquio syndrome is an inherited condition, which means it is passed down through families. If both parents carry a nonworking copy of a gene related to this condition, each of their children has a 25% (1 in 4) chance of developing the disease. This is called an autosomal recessive trait.
Autosomal recessive
Autosomal recessive is one of several ways that a trait, disorder, or disease can be passed down through families. An autosomal recessive disorder me...
There are 2 forms of Morquio syndrome: Type A and Type B.
-
People with Type A do not have a substance (
enzyme
) called galactosamine-6-sulfatase.
Enzyme
Enzymes are complex proteins that cause a specific chemical change in all parts of the body. For example, they can help break down the foods we eat ...
- People with Type B do not produce enough of an enzyme called beta-galactosidase.
The body needs these enzymes to break down a long strand of sugar molecules called the keratan sulfate sugar chain. In both types, abnormally large amounts of glycosaminoglycans build up in the body. This can damage organs.
Symptoms
Symptoms usually start between ages 1 and 3. They include:
- Abnormal development of bones, including the spine
- Bell-shaped chest with ribs flared out at the bottom
- Coarse facial features
-
Hypermobile joints
Hypermobile joints
Hypermobile joints are joints that move beyond the normal range with little effort. Joints most commonly affected are the elbows, wrists, fingers, a...
- Knock-knees
- Large head
-
Short stature
with a particularly short trunk
Short stature
A child who has short stature is much shorter than children who are the same age and sex. Your health care provider will go over your child's growth ...
-
Widely spaced teeth
Widely spaced teeth
Widely spaced teeth can be a temporary condition related to normal growth and the development of adult teeth. Wide spacing can also occur as a resul...
Exams and Tests
The health care provider will perform a physical examination. Examination and testing may reveal:
- Abnormal curvature of the spine
-
Cloudy cornea
Cloudy cornea
A cloudy cornea is a loss of transparency of the cornea.
- Heart murmur
-
Hernia in the groin
Hernia in the groin
A hernia is a sac formed by the lining of the abdominal cavity (peritoneum). The sac comes through a hole or weak area in the strong layer of the be...
-
Enlarged liver
Enlarged liver
Hepatomegaly is swelling of the liver beyond its normal size. If both the liver and spleen are enlarged, it is called hepatosplenomegaly.
- Loss of nerve function below the neck
- Short stature (especially short trunk)
Urine tests are usually done first. These tests may show extra mucopolysaccharides, but they can't determine the specific form of MPS.
Other tests may include:
-
Blood culture
Blood culture
A blood culture is a laboratory test to check for bacteria or other germs in a blood sample.
- Echocardiogram
- Genetic testing
-
Hearing test
Hearing test
An audiometry exam tests your ability to hear sounds. Sounds vary, based on their loudness (intensity) and the speed of sound wave vibrations (tone)...
-
Slit-lamp
eye exam
Slit-lamp
The slit-lamp examination looks at structures that are at the front of the eye.
- Skin fibroblast culture
-
X-rays
of the long bones, ribs, and spine
X-rays
X-rays are a type of electromagnetic radiation, just like visible light. An x-ray machine sends individual x-ray particles through the body. The im...
People with Morquio syndrome should have MRI of the lower skull and upper neck to determine if their upper vertebrae are underdeveloped.
Treatment
The U.S. Food and Drug Administration has approved a medicine for Morquio syndrome type A, called elosulfase alfa (Vimizim). It is given through a vein (IV, intravenously). Talk to your provider for more information.
Symptoms are treated as they occur. A spinal fusion may prevent permanent spinal cord injury in people whose neck bones are underdeveloped.
Support Groups
For more information and support, contact one of the following organizations:
- The National MPS Society -- www.mpssociety.org
- Canadian Society for MPS and Related Diseases -- www.mpssociety.ca
- Society for MPS Diseases -- www.mpssociety.co.uk
Outlook (Prognosis)
Cognitive function (ability to think clearly) is usually normal in people with Morquio syndrome.
Bone problems can lead to significant complications. For example, the small bones at the top of the neck may slip and damage the spinal cord, causing paralysis. Surgery to correct such problems should be done if possible.
Heart problems may lead to death.
Possible Complications
These complications may occur:
- Breathing problems
-
Heart failure
Heart failure
Heart failure is a condition in which the heart is no longer able to pump oxygen-rich blood to the rest of the body efficiently. This causes symptom...
- Spinal cord damage and possible paralysis
- Vision problems
- Walking problems related to abnormal curvature of the spine and other bone problems
When to Contact a Medical Professional
Call your provider if symptoms of Morquio syndrome occur.
Prevention
Genetic counseling is recommended for couples who want to have children and who have a family history of Morquio syndrome. Counseling is also recommended for families who have a child with Morquio syndrome to help them understand the condition and possible treatments. Prenatal testing is available.
References
National Institute of Neurological Disorders and Stroke. Mucolipidoses Fact Sheet . Office of Communications and Public Liaison. Bethesda, MD; Publication No. 03-5115. February 13, 2007.
Pyeritz RE. Inherited diseases of connective tissue. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 260.
Spranger J. Mucopolysaccharidoses. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics . 19th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 82.
Wraith JE. Mucopolysaccharidoses and oligosaccharidoses. In: Saudubray J-M, van den Berghe G, Walter JH, eds. Inborn Metabolic Diseases: Diagnosis and Treatment . 5th ed. New York, NY: Springer; 2012:chap 40.
Review Date: 4/20/2015
Reviewed By: Chad Haldeman-Englert, MD, FACMG, Wake Forest School of Medicine, Department of Pediatrics, Section on Medical Genetics, Winston-Salem, NC. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.