Diagnosing Hunter Syndrome

With a greater understanding of just how serious Hunter Syndrome is, it's pretty obvious that the earlier this disease is diagnosed, the better it is for the patient right?
But have you ever wondered how this disease is diagnosed? Fret not, because that's what I'll be blogging about today!

First, a quick recap on the basics of Hunter Syndrome

• A genetic disease that causes a deficiency in the enzyme iduronate-2-sulfatase
• X-Linked recessive disease, guys are more likely to be affected by this disease
• Most commonly results in an affected individual when the defective X chromosome is inherited from a carrier mother.
• Rare, with approximately 1 in 150,000 males affected worldwide
• This enzyme deficiency has a wide range of effects on the body

Common inheritance patterns of Hunter Syndrome

There are two main types of diagnosis for this disease.

The first, Pre-natal diagnosis, is done before the child is born when prospective parents suspect that their child might have a defective gene, generally due to either side having a medical history of Hunter Syndrome in their families.

This is mainly done through amniocentesis, where the fluid surrounding the fetus is sampled to obtain the amniotic cells present inside. These cells contain the genes of the fetus, which can then be karyotyped to check if the fetus does have Hunter Syndrome.

However, sometimes some children develop Hunter Syndrome even though their parents have no history of the disease.

These children are usually diagnosed in the early stages of development (1-2 years) but some only develop symptoms in their early 20s

Some of the more common symptoms that serve as warning signs are

• Changes in facial features such as broadening of the nose bridge
• Enlarged spleen or liver
• Skeletal deformities

However, these symptoms alone do not mean that the child does have Hunter Syndrome.

To confirm the diagnosis, doctors prescribe several laboratory tests, the most common being 

• Blood tests for iduronate-2-sulfatase activity
• Urine tests to measure the amount of Glycosaminoglycans in the urine

In addition to these, genetic testing can also be done to check for the presence of  a defective I2S gene.

That's all I have for you today,

Next up: Treating Hunter Syndrome

Sources:

http://ghr.nlm.nih.gov/handbook/illustrations/xlinkrecessivefather

http://ghr.nlm.nih.gov/handbook/illustrations/xlinkrecessivemother

http://rarediseases.about.com/cs/huntersyndrome/a/022204.htm

http://www.mayoclinic.org/diseases-conditions/hunter-syndrome/basics/tests-diagnosis/con-20026538

http://nursingcrib.com/wp-content/uploads/2014/06/amniocentesis.jpg