Morquio Syndrome – Facts, Symptoms, Treatment, Pictures
Morquio Syndrome or Muco-polysaccharidosis is a disease in which the body cannot break down long chains of sugar molecules. It is an unusual hereditary disorder marked by improper intra-cartilaginous bone development which results in the deformity of skeleton and dwarfing. Spine and long bones of the body are particularly affected.
People with Morquio syndrome have normal life expectancy and absolutely normal intelligence. Also cognitive function is normal in these patients. The syndrome occurs in just 1 out of 200,000 people. The symptoms become visible in 1 to 3 years of age. The family’s history of Morquio syndrome is the main factor in developing this syndrome.
Also known as MPS IV, Morquio Syndrome is an autosomal recessive condition and identified as lysosomal storage disease. It is characterized by lysosomal accumulation of glycoprotein, glycolipids and glycosaminoglycans because of deficit lysosomal hydrolases which are responsible for degradation of glycoconjugates.
Morquio Syndrome is associated with certain complications such as breathing problems, heart problems, problem in walking, eye-sight and spinal cord damage or even paralysis.
Causes of Morquio Syndrome
Morquio Syndrome is an inherited disease i.e. it is passed from parents to their children through genes. The fact that parents should pass gene to their child in order to get this syndrome makes Morquio syndrome to be of autosomal recessive trait.
It occurs due to lack of enzymes N-acetyl-galactosamine-6-sulfatase and beta-galacctosidase. Morquio Syndrome is caused because of inability to break down sugar molecules due to lack or absence of muco-polysaccharides.
Types of Morquio Syndrome
It is of two types:
Morquio Syndrome Type A: It is caused because of the deficiency of enzymes called galactosamine-6-sulfatase. This results in accumulation of keratin sulphate and glycosaminoglycan in body tissues. Patients with severe Type A have shortened life span which is up to three decades.
People with Type A have abnormal skeletal and nervous system. In this condition, patients are born normal and gradually they begin to develop growth retardation. The abnormalities seen in patient with Morquio Syndrome Type A include short-trunk dwarfism, platyspondylia, scoliosis, short phalanges, hyperlordosis and odontoid hypoplasia.
Morquio Syndrome Type B: People who have beta-galactosidase deficiency develop Type B Morquio Syndrome. Morquio Syndrome Type B is milder than Type A and is a result of abnormalities in gene different from those causing Type A.
Type B is marked by skeletal dysplasia causing short stature, scoliosis, odontoid hypoplasia, platyspodylia and protrusion of sternum. The good part of Type B is that central nervous system is not involved in this disease and patients have normal intelligence.
The deficiency of enzymes both in Type A and Type B are responsible for breakdown of long keratin sulphate sugar chain. Consequently huge amounts of glycosaminoglycans get accumulated in the body and brain which gradually begin to cause damage to the organs.
Symptoms of Morquio Syndrome
This condition is recognized in first two-three years of life and this condition persists till bone growth stops in or after late adolescence. In this disorder, the vertebrae of spine become flat and wedge-shaped; the back deforms and spinal cord may compress. Also, paired bones have uneven development and thigh bones are malformed which further causes dislocated hip and knock-knees. The symptoms of Morquio syndrome also include circulatory abnormalities and clouded corneas.
The characteristics of Morquio Syndrome include:
- Short stature
- Corneal clouding
- Cervical instability
- Moderate kyphosis
- Mild gebua valga
- Mild pectus carinatum
- Odontoid hypoplasia
- Short neck
- Progressive Deafness
- Joint laxity
In order to examine Morquio Syndrome, the doctor will do a physical examination as most of the symptoms are noticeable without any special tests. The test will reveal conditions like abnormal spine curvature, enlarged liver, short stature, abnormal or lost nerve function in the parts below neck, heart murmur, inguinal hernia and cloudy cornea.
The doctor would first ask to do a urine test which may show extra muco-polysaccharides. Thereafter the doctor may ask to take other tests including blood culture, genetic testing, echocardiogram, hearing test, skin fibroblast culture and X-ray of spine, ribs and long bones. In order to determine if the upper vertebrae are developed properly or not, MRI of lower skill and upper neck should be done.
Morquio Syndrome Treatment
Since this is a genetic disease, there is no treatment for Morquio Syndrome. However researchers are still working on finding treatment for this syndrome. Spinal fusion and enzyme replacement are also being tested in treating the symptoms of Morquio syndrome as and when they occur. Other possible future treatments also include gene therapy and allogenic bone marrow transplantation.
Some authorities advise affected parents to undergo upper cervical spine fusion. Surgical operations like corrective knee surgery, femoral osteotomies, hip replacement and total knee replacement are also suggested.
Genetic counselling is recommended for those who have Morquio syndrome in their families. Parents who have child with the syndrome should go for counselling to understand the condition and treatment if possible.