Re: thanks--inheritance question

[Guest guest]

Hi ,

According to " The Genetics of Mitochondrial Disorders " , Amy C.

Goldstein, MD and Carolyn Bay, MD, inheritance of Complex II

disorders is autosomal recessive. " Complex II has four or five

polypeptides, all encoded by the nuclear genome. Complex II

deficiency can be caused by multiple mutations involving the

flavoprotein gene and has autosomal recessive inheritance. "

From the UMDF newsletter feature article Summer 2003.

To read more about how autosomal recessive inheritance works, go to

the UMDF site and click on information center; patients and

families; genetics.

MDA also has a detailed article on genetics that includes an

illustrated explanation of autosomal recessive inheritance.

http://www.mdausa.org/publications/gen_inhr.html

You might also be interested in an article in the UMDF newsletter

Fall/winter 2001 called " How Common Are Mitochondrial Disorders? "

Barbara

> thanks for the help on the biopsy report, Alice the link was great.

> sounds like complex II isnt very common.

> Still cant believe I actually have answers..It has been a long

wait.

> Now I am curious ...if complex II is a nuclear encoded gene...how

is

> it passed on? mom or dad? I am just wondering where it came from.

> Thanks again

>

[Guest guest]

Hi again,

rs can sometimes be symptomatic. This is not common, but it

can happen and has been reported in the medical literature. They are

known as " manifesting carriers. " However, in your case, the profound

deficiency noted in your report would probably have to be the result

of two mutations, not one. Ask your doctor about their

interpretation in your case, but generally in recessive disorders,

one mutation (carrier status) will reduce enzyme activity by half.

It takes two mutations, one from each parent, to produce a profound

deficiency.

From what I remember about your family, Dr. Naviaux also diagnosed

your kids with another primary genetic metabolic disorder--forgotten

the exact name at the moment, but I believe it was an inborn error

in carbohydrate metabolism. I remember when you posted this

breakthrough a couple of years ago after testing at UCSD.

Assuming that diagnosis is still on the table, here is my amateur

(!!) analysis. Your kids MAY have each inherited one copy (carrier

status) of your complex II mutation, along with the other metabolic

defect that Dr. Naviaux found. In other words, your kids could be

carriers for complex II and also have a full-blown case of the other

disorder. You, on the other hand, would presumably be a carrier for

the original diagnosis by Dr. N and have a full-blown case of

complex II. Dr. Vladutiu believes that combined defects tend to make

both worse than they would be alone and that even carrier status for

a second disorder can complicate the metabolic situation.

IF the people working on your complex II defect could identify which

specific complex II mutation you carry, then they could use blood to

check your children for that particular complex II mutation and see

who has what and how many. It gets very complicated when there is

more than one disorder in one family. We've been through all this

too!

Take care,

Barbara

> Barbara,

> thanks , leaves me wondering then how all three of my kids got it

and my

> hubby doesnt have it. Also I thought carriers of Autosomal

recessive disorders

> dont have it just carry it so how would I pass it on to my kids,

especially all

> of them...

>

>

>

>