Hi,

Thanks to a very observant and knowledgable neurologist, I was quite quickly diagnosed with KD (at the age of 54) in summer 2008. At present, I am fortunate in that I can only describe my current symptoms (detailed in the previous thread started by Indiana Jim) as having nuisance value, and I really cannot complain about my quality of life.

However, I accept that this situation can and will change, and am curious whether any KDA members have been able to look into family history (past and recent) and identify whether symptoms exhibited by family members followed a particular pattern. I am especially interested in whether they can relate the symptom type, severity, and rate of progression to their own experience. I appreciate that the condition was not named KD or, indeed, accurately diagnosable until relatively recently and so it is improbable that any condition suffered by our forebears would have been so labelled.

I haven't told my 81 year-old mother the full facts about my condition, as she would feel too distressed and 'responsible'. However, I am considering how to elicit information from her about my recent ancestors who may have exhibited symptoms of KD. Her father, a coal miner, died of pneumonicosis ('dust disease') before I was born, and it seems highly probable that this was exacerbated by KD. Although my brother and sister know the situation, I have yet to tell my cousins that they and their progeny may be affected. I am delaying this pending consultation with a geneticist, digging more into maternal family history, and deciding upon the most appropriate and sensitive way to broach the subject.

Comments upon any aspect of the above would be much appreciated.

Cheers,

John

You have asked a good question. Several associates have done some study of the family. I have two brothers with KD (one has passed away) and we believe an uncle had it because he was confined to a wheelchair in his early fifties (but was never diagnosed).

The question of severity of symptoms and timing are ones that have not been studied. Doctors stated that the higher the number of CAG Repeats, the earlier the onset and more severe the symptoms. However, my two brothers and I are different in severity/onset/actual symptoms. Some are the same, but many are not. My neurologist believes that many factors weigh in on these items. Over-use of certain muscles, earlier injuries, extended use of certain muscles, non-use of certain muscles, other health issues, and "stress" all play a role in determining onset, severity, and symptoms. I know of KD'rs that are still running marathons in their late 40's and others in the 60's that still snow ski. Some have still worked into their 60's (manual labor) while others have had to quit or find other employment in their 40's and early 50's. Some had early onset and then plateaued for years. Others had later onset but experienced an extremely fast degeneration. We are all individuals and I don't believe one determining factor (such as heredity) decides how, when, and how fast.

John, my husband has KD. He, also has other siblings that are affected. There are 3 brothers (1 of which has passed away - not from KD) and a sister that is a carrier. We also believe there were other family members (uncles and cousins) that actually had KD but been diagnosed as having something different. I will mention your question to him and ask if he would reply to your concerns.

Many thanks, both, for your responses.

Bruce - your opinion re. the individual nature of the KD experience is pretty much in line with what I expected. I guess that even if data were available, the sample size possible from such a small group of sufferers would have inadequate statistical validity to provide the newly-diagnosed with a reliable prognosis.

cdh17901 - I look forward to reading your husband's comments.

Regards,

John

Hi there, sorry for not checking on this sooner, I was just reviewing the site again and realized I had not posted any further information. I mentioned the posts to my husband and he now has a question...has anyone ever been able to find out what actually causes the genetic defect in the first place? Then, we got to wondering...How would the children be affected if BOTH parents were affected?

The reason for asking is, as I mentioned in my earlier post, ALL the males (4) in my husband's family have KD; AND his only sister is a carrier. So the 50% chance doesn't seem to fit here.

Thanks.

GENETIC COUNSELING/INHERITANCE

That is a good question. What would be the odds of having a husband and wife with the defective gene? I pulled this from the web site for a starting point:

"Are you wondering if your children are or will be affected by this Disease?

If the mother is the only carrier of the defective gene: there is a 50 % chance of passing the affected gene on to male children (in which they would develop symptoms in adulthood). The chance of passing the defective gene on to female children is also 50 % (in which they would be carriers of the gene, but usually do not ever develop actual symptoms).

If the father is the only carrier of the defective gene your chances of passing the defective gene to a male child are 0 %. However, it is 100 % certain that you would pass this gene on to your female child, and she will be a carrier of the gene."

Now, it was explained that they used averages in determining percentages. Out of a hundred cases reported, for example, you could have one case where every child is passed the defective gene. In another case, perhaps only one child is passed the gene. As you average out the number over 100 cases, it nears 50%.

Another example that might explain it better. A coin is either heads or tails when flipped (50-50 chance). If you have 100 people flipping a coin not every person flipping the coin will have a heads one time and a tails the next. Some might have three heads in a row come up before a tail. Conversely, another might have four or five tails come up before a heads. However, when you average out all of the heads and tails that come up for the 100 people, it should be close to 50% for each.

Using my family, out of seven boys in my family, three had the defect (43%). Out of three girls, none have the defective gene (0%).

I have heard of many different scenarios over the several years I have been associated with the KDA. As many times as I heard that all the males in a family have it, I also heard as many stories that only one male had it. I call it the "luck of the draw".

Reference what actually caused the first defect in the gene (if that is what you are asking), I don't think anyone knows. The defective gene is a mutation of a healthy gene. It does not function in the same way a healthy gene functions in regards to the processing (cleaning) of the androgen receptor. Testosterone is like a poison to the gene.

If I did not answer your question correctly, please let me know and I will ask someone that is better at explaining these things.

This message has been edited. Last edited by: Bruce,

Hi Bruce. Thanks for the reply. The reason for my inquiry was because I have heard that there have been some instances, although rare, where the female actually exhibits symptoms of KD. I believe there was even a post on our forum at one time about females exhibiting symptoms. This may not even be a possibility but I had to ask anyway.

If that were to be the case, would she also be considered as having KD and not be considered just a "carrier"?

If that were true and it did turn out that she actually had KD and she and a male that actually had KD had a child, what would the expected outcome be?

This is what I meant when I asked what if BOTH parents were affected. Is that even possible?

Another thought comes to mind as well; has there been any study into family trees as to whether this genetic defect could have something to do with great-great grandparents, or great grandparents, etc. marrying within the same family? For instance 2nd or 3rd cousins marrying one another?

Am I also correct to assume this disease is not specific to one ethnicity as some other diseases are?

Thanks!

WOW! You are testing my knowledge and I might not be the best person to answer some of these questions.

Ethnicity: KD, as far as researchers know, has no boundaries. We have associates from many countries around the world including the Middle East, Africa, Japan, Indonesia, Australia, South America, Europe, etc.

Carriers: It is not uncommon for carriers to exhibit symptoms. The age of onset and severity of the symptoms are far less than that of a male, however, and often go unnoticed. We know of several cases when symptoms began to show up in the fifties and sixties for certain carriers. Again, they are milder and not quite as noticeable. Personally, since KD is becoming more know and the testing is relatively simple, I feel that we might hear of more cases where symptoms are noticeable in carriers.

Both Parents: Yes, it is a possibility for both parents to have KD, but researchers state that would be very rare (1 in 40,000 meets and marries 1 in 40,000). Since the carrier may still have a good "X" Chromosome, it is my understanding that the odds would not change for the male offspring. The same odds would also apply for the female offspring (again since their is still a good "X".

Now, a question that Dr. Fischbeck commented upon a couple of years ago, is can a carrier have two defective "X" Chromosomes. He said that was a possibility, but that he has never seen that happen nor heard about it happening. In that case, every offspring would be passed the defective gene.

Hi Bruce!
Thanks for the reply, I believe you have now answered my question and at the same time given me more to ponder. It looks like we'll be trying to look a little deeper into our family tree.

I found these diagrams on the Swedish Web Site that discusses Kennedy's Disease. I think it does a nice job of showing the different potential combinations. The link to the site is: Kennedy's Disease .

Heredity

Kennedy disease is an inherited X-linked recessive disorder. This means that the mutation causing the disease is located on the X chromosome, which is one of the sex chromosomes. While women have two X chromosomes, men have one X chromosome and one Y chromosome. Since the mutated gene is recessive, female carriers are protected by having a second X chromosome with a normal gene, whereas men who inherit the mutated gene develop the disease. X-linked recessive disorders are therefore found only in men, but are passed down via female carriers of the mutation. Sons of female carriers run a 50 per cent risk of inheriting the disorder, and daughters run the same risk of becoming carriers. A man with an X-linked recessive disorder cannot pass it down to his sons, but all his daughters will be carriers of the mutation.