Undetected mutations

[charlie]

One thing I did learn today from our very frustrating appointment is the undetected mutations of HFI. As several of us have said the genetic tests have come back as no detected mutations. Well apparently this is because if 2 new carriers come together they produce a new mutation which won't be picked up for a long time.

[venusillegitima6]

Charlie, I'm not good at science and I would really like you to explain me the thing about mutations

[charlie]

OK, I will try. But try this web site too.
learn.genetics.utah.edu/archive/mutations/index.html

Basically we are all made up of DNA which are formatted in very specific sequences of amino acids and this is what dictates our appearance, colour, body functions etc etc etc. Every so often the code goes wrong whilst we are developing in the womb and this causes a mutation. Instead of the code ABCDEFG it develops as ABCDEGF to use a simple idea. Depending on which part of the chain the mutation occurs dictates what problem it causes. Now over the years genetisists have identified some of the mutations and what disease they cause (don't ask me how the identified the HFI ones - Fred may know). But these mutations may occur on a random basis say in your father but being a new code change hasn't been identified yet, this then meets another one in your mother, they cause them to be carriers but asymptomatic but then when you are made they combine to create you as a symptomatic HFI sufferer. In years to come they may be able to map this mutation but it takes a long time.

Does this make sense? Basically for HFI it is autosomal recessive and both parents have to be carriers, there is a one in four chance of it coming out in the child. Its a bugger if you are the one.......................

[venusillegitima6]

Thanks Charlie

Yes, I actually know about the 25% chance of having a HFI child if both parents are the carriers of the gene. Basically, there's also 25% chance that the child will not have HFI nor be the carrier, and 50% of chance of a child not having HFI but being the carrier. I didn't know about the mutations, though, but it makes sense.

For example, I don't know anyone in my family to have HFI, not even my great-grandparents (at least I don't know they had any symptoms). Now, for the theory that both parents have to be the carriers it implies that at least one parent of my mom and one parent of my dad had to be the carriers and that's entirely possible. Now, I'm wondering if at least on one side of my family there was a mutation instead of history of HFI gene carriers...

I've also calculated the chance of my kids having HFI. If my husband (or the father of my children, it doesn't matter, hehe) doesn't carry the recessive gene that all of my kind will just be the carriers, but if the father is a carrier than there is 50-50 chance of a kid having HFI.

I wonder how many HFI people have HFI children