The genetics of Hunter Syndrome

Welcome back everyone, today we'll be talking about the genetics of Hunter Syndrome and how it is passed down from one generation to another.

Hunter Syndrome is a genetic disorder, that is, it can only be 'caught' through your parents. But what are the chances of you getting this disease?

To understand this, we have to first understand the genetics of this disease.

Hunter Syndrome is an X-linked recessive disorder that is caused by a defective gene (IDS) on the X chromosome that codes for an enzyme called iduronate-2-sulfatase (Remember this name, we'll talk more about this enzyme later).

The 46 chromosomes in a normal human, now in a nice picture.
The affected X chromosome is highlighted in red

Since this disease is X linked, guys(XY) are more likely to be affected by this disease as girls(XX) have a backup gene on their other X chromosome even if they inherit a defective copy of the IDS gene.

However, since one of their X chromosomes has the defective gene, these girls are said to be carriers.

Guys don't have this backup plan though, since they only have one copy of the X chromosome so if they do inherit a defective copy...

Tough luck eh?

Since this disease is X-linked, inheritance patterns will depend on how affected the parents are.

Obviously, if both parents are affected, all their children will also be affected, but what about carrier mothers?

  

Are there any other possible inheritance patterns? Let me know what you think in the comments section!

Next up: The Biochemistry of Hunter Syndrome

Source:

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

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

https://www.mun.ca/biology/scarr/Human_Karyotype.html
http://www.eurogentest.org/index.php?id=623
http://ghr.nlm.nih.gov/handbook/inheritance/inheritancepatterns