Sly Syndrome: Causes, Symptoms, Treatment, Life Expectancy, Prognosis
What is Sly Syndrome?
Sly Syndrome which is also known by the name of Mucopolysaccharidosis is a progressive congenital disorder which tends to affect almost all of the tissues and organs of the body. The severity at which this condition affects a child is although variable. At its worst, Sly Syndrome can cause the child to have excess fluids present in the body even before birth. In such cases, either the baby is stillborn or is only able to survive a couple of hours after birth.
The babies who tend to have milder form of Sly Syndrome tend to show signs and symptoms of this condition in early childhood with them having a high head, a condition called as macrocephaly. There is also excess fluid buildup in the brain resulting in hydrocephalus. Such children also have distinct facial features and have an abnormally large tongue.
Liver and spleen enlargement are also one of the signs of Sly Syndrome. Additionally, children with Sly Syndrome will have heart valve defects and umbilical hernia. There may also be narrowing of the airways making breathing difficult for some children with Sly Syndrome making them prone to frequent upper respiratory infections. Some children may also develop sleep apnea as a result of Sly Syndrome.
Children with Sly Syndrome also tend to have certain ocular anomalies which may cause vision disturbance or in some cases complete vision loss. Hearing loss is also one of the common findings in children with Sly Syndrome. Additionally, children have frequent ear infections and hearing deficits as a result of Sly Syndrome.
Children affected with Sly Syndrome tend to have developmental delays and intellectual disability, although normal intelligence is not affected by Sly Syndrome. Some of the deformities that tend to get more prominent as the child grows is a small stature and other joint and bone deformities as a result of Sly Syndrome.
What are the Causes of Sly Syndrome?
The root cause of Sly Syndrome is a mutation in the GUSB gene resulting in a deficiency of an enzyme called beta-glucuronidase. As a result the mutation of this gene, the various deformities in a child develops. The main function of the enzyme beta-glucuronidase is breaking down of sugar molecules.
If the enzyme does not function properly it results in accumulation of these large sugar molecules, lysosomes to be more specific, causing what is called as lysosomal storage disorder.
The gradual accumulation of the molecules of the sugar results in the lysosomes getting enlarged which causes the various organs of the body to get enlarged causing Sly Syndrome. This is an autosomal recessive trait meaning that two copies of the defective gene from each parent are required for the development of Sly Syndrome.
What are the Symptoms of Sly Syndrome?
The symptoms of Sly Syndrome are variable and differ from person to person depending on the severity of the disease condition. Some of the most prominent symptoms of Sly Syndrome are:
- Mental retardation
- Developmental delays
- Intellectual disability
- Abnormally short stature
- Short trunk
- Intestinal abnormalities
- Abnormalities of the eyes
Musculoskeletal deformities to include prominent breast bone, frequent dislocations of the hip, frozen joints, club foot, genu valgum, kyphosis in some cases
How is Sly Syndrome Diagnosed?
Sly Syndrome can be easily diagnosed through a detailed clinical evaluation of the patient to include a detailed history of the patient and the family history of any other members of the family being diagnosed with this condition.
If Sly Syndrome is suspected, then specific tests to measure the levels of beta-glucuronidase will be done in the blood to look for any accumulation or lysosomal enlargement.
Once the testing show elevated levels of this molecule then genetic testing for mutations of GUSB gene will be done which will confirm the diagnosis of Sly Syndrome.
How is Sly Syndrome Treated?
There is no specific treatment for Sly Syndrome. The treatment is mainly supportive and symptomatic. Surgery may be required for treating bone deformities and conditions like hernias. It may also be required for treating ocular abnormalities and cardiovascular defects if any are identified.
It should be noted here that people with Sly Syndrome tend to be very sensitive to anesthesia due to malformed airways or defect in the cervical spine and hence the anesthesiologist should be very careful while administering anesthesia for doing any surgeries in patients with Sly Syndrome.
Genetic counseling is also recommended for people who have a child with Sly Syndrome or who have risk factors for their off springs to develop Sly Syndrome.
What is the Prognosis of Sly Syndrome?
The overall prognosis for Sly Syndrome is dependent on the severity of the symptoms. While in many cases, the prognosis may not be that good and the child may not survive more than a few months but there have been cases where the patient has survived until adulthood but with significant deficiencies as a result of Sly Syndrome.