Re: Digest Number 626

[Guest guest]

I was told by my daughters pediactric GI doc that both parents have to be a carrier of the gene for a child to get the disease. He told me that 1 out of 4 offsprings will get the disease, one will not get it or be a carrier and the rest will be carriers.

I was the one in my family of four sisters to get the disease, none of my sisters have been diagnosed. Two of my sisters had the biopsy which was negative, all seem to have symtoms. Neither of my children have been diagnosed, one was biopsied, the other had high antigliadin IGA(?).

The only other person in my family that was dx with Celiac was my uncle on my fathers side.

Donna

In a message dated 12/30/2004 1:23:27 PM Central Standard Time, SillyYaks writes:

Message: 1 Date: Wed, 29 Dec 2004 20:51:59 -0000 Subject: Re: another genetic question! *BARGE*I hope you don't mind my barge. It's completely incorrect that genetic issues are only passed through the mother, as your son claims he was told. I suspect that your son may be confusing general genetic issues with either sex linked traits (disorders such as hemophilia or color blindedness that, because of the structure of the X and Y chromosome, males are more likely to get than females) or mitochondrial DNA, which is indeed inherited only from the maternal source. CD/DH is connected to neither of these issues.Of course, there is a third, more horrific possibility, and that's that the teacher actually said that genetics only come through the maternal side, but as the spouse of a teacher, I know that 99.9% of the time, "what the teacher said" gets very garbled between the classroom and the home (-:Hope that helps.> > I think I'm probably addressing this question to Philip D., who > appears to be very well versed in genetics! Thank you for you > response to my first question. I must admit that I didn't > understand all of the specifics, but I get the jist of it.> > This question is to settle a question between my 15 yr old and me. > Although he understands that he is at risk for CD/DH, he insists > that his high school biology teacher told the class that he (my son) > cannot transmit actual CD to his own kids because 'genetic diseases > are only transmitted thru the maternal genes'. Therefore, his > children will not develop CD, though they may be carriers, and if he > has a daughter, her children could have actual CD. I tried to > explain that I don't believe that's true (ie, Woody Guthrie's kids > being at risk for Huntington's, therefore, genetic diseases can be > passed thru paternal genes), but you know that Moms don't know > anything these days!> > Can you help settle this question?> > Hope you, and all the 'SillyYaks' had a great Holiday Season. This > was my first 'GF' and although there were some changes in our > traditional foods and treats (Santa no longer likes White Chocolate > dipped Oreos, he likes GF gingersnaps) it was still the same > wonderful holiday.> > Blessings to all,> > Stormy________________________________________________________________________________________________________________________________________________Message: 2 Date: Wed, 29 Dec 2004 22:15:16 -0000 Subject: Re: another genetic question!> > > I think I'm probably addressing this question to Philip D., who > appears to be very well versed in genetics! Thank you for you > response to my first question. I must admit that I didn't > understand all of the specifics, but I get the jist of it.> > This question is to settle a question between my 15 yr old and me. > Although he understands that he is at risk for CD/DH, he insists > that his high school biology teacher told the class that he (my son) > cannot transmit actual CD to his own kids because 'genetic diseases > are only transmitted thru the maternal genes'. Therefore, his > children will not develop CD, though they may be carriers, and if he > has a daughter, her children could have actual CD. I tried to > explain that I don't believe that's true (ie, Woody Guthrie's kids > being at risk for Huntington's, therefore, genetic diseases can be > passed thru paternal genes), but you know that Moms don't know > anything these days!The diseases that he is refering to are called X-linked genes and mt genes. The X chromosome is carry in 2 copies in females and a single copy in males. Recessive genes (generally loss of function) generally have no affect on females because they have an alterative copy expressed in about 1/2 the cells in the body. And instance of X-linked gene is the hair color genes in the cat, the calico cat for instance can only be female, and males either have one color or the other. The patches on a female calico cat represent the expression of one X-chromosome while the other is turned off. I thought that is interesting. mitochondrial genes, >95% are inherited from the mother, a few to no percent from the father. This is because the male sperm has but a few mitochondria and the egg has bunches of them. The only positively known genes that are associated with CD are on the autosomal chromosome #6, these genes can be passed at equal risk from maternal or paternal lines. The other known risk factors differ markedly between different groups and are pretty much an unknown. The recent paper I mentioned in gliadin science makes a passage that most of the examples of CD they had in thier study (statistically insignificant based on N) indicate that the father passed the disease to his offspring) The X chromosome is an average to large chromosome, humans have 22 other chromosomes, the risk of a factor being passed on X, if that factor is unknown is between 1:11 and 1:22. mtDNA are 16500 nucleotides in length (compared to 3,000,000,000 for the human genome) so that there is not a high risk that whatever other factors you have, that they are passed on X or mtDNA. As I have pointed out the one way of quelling the issues of familialCD in family members is to get them DQ typed, if they do not have thesusceptibility type then there is a very low chance they will have a life threatening disease. The secondary issue about their children, they can get those children typed at birth and know with certainty the risk, so they need not even worry about this now if they do not have the DQ type. There is only a 40% chance they will marry someone with DQ2.3 or DQ8 and there is only a 50% per child that the child will aquire the spouses DQ, so that the risk is only 20% per child in the F2 generation if the son does not have the DQ type, we can multiply this by the non-DQ associated risk and the risk in the F2 is considerably lower than the F1 risk, but still higher than the risk of general population, including DQ2.3 and DQ8 bearers. IOW don't put the cart before the horse. Secondarily I don't consider Coeliac Disease a genetic disease, the DQ types are not diseased DQ types, and while the susceptibility is inherited, the culprit for CD is the massive artificial selection that has occurred with grain crops in order to increase their agrarian properties. Does one blame scherosis on weak liver genes or or alcohol consumption. These properties are also the cause of late onset diabetes in most individuals, and other health related disorders. Sceince might find a way in the next few years to select for alpha/gamma gliadin producing crops that do not contain the susceptibility T-cell sites and CD may disappear in all subsequent generations. All that is required to do this is to screen wheat for the proteins that produce these genes, sequence them and find a few mutants that no longer possess the disease process. In the meantime I should remind everyone that three continents of peoples lived 1000s of years without eating wheat, rye or barley and the food cultures of these peoples have made outstanding contributions to food culture diversity around the world. So be an explorer and explore these other food types and enjoy life.