Babbocat

Sorry for long delay in reply. The basic picture is that the mother-in-law had a cancerous lump in her leg. On a day in the middle of August 2013 we had intercourse, then my wife went off for a few days at the beach with her parents, then they all came back together and about a week or so later her mother went into hospital, into "nuclear medicine" had an isotope to show them the ganglia, etc. The rest as i have described it above. My wife eats a lot of fried meat, hardly any vegetables, a lot of pulses (lentils, beans, etc.), no fish except for lots of tuna (which for me is a no-no), drinks lots of Coca-Cola, although due to my insistence things have become more normal over the years. The meat she eats is normal quality, not necessarily cheap ever. And she doesn't eat any processed food, everything is fresh. In 33% of cases, the disease our son has is a spontaneous mutation ("de novo"), in the other 66% it is inherited through the mother. The mutation is always on the X chromosome. Only boys really get it because if they have a mutation on their X chromosome they do not have another X to fall back on.

Thanks Swansont. As far as I know my mother in law was injected with some kind of isotope which helped to clear up the tumour she had in her leg. My wife visited her in hospital I think about a week after we had intercourse. You say that "AFAIK there's no way to trace this to a specific event". So do you mean that even if my wife had walked into the room where her mother had this radiotherapy, there do not know if this could cause a gene mutation? Thanks Sensei, so if I am reading this right, really there is very little reason that this visit to the hospital could have caused the gene mutation in any way? It is more likely then that it was just in the (our) genes, or was caused by diet, for example? I mention diet because my wife has a very strange diet, she eats lots of meat and very few vegetables, and hardly any fruit.

Hi all, I wonder what your all think about all the following situation. We have a son who was born with a de novo (spontaneous) mutation for DMD (Duchenne's muscular dystrophy). There is no family history of this disease on either side, plus my wife was tested and came out negative as a carrier. Unfortunately a week/two weeks after conception, my wife ended up visiting her mother in hospital, she was getting a cancerous lump in her leg removed and part of the treatment was with a radioactive isotope. On the first visit (I wasn't there), the specialist told her and my father in law of the precautions, one of which is if you are possibly pregnant then there should be no contact with her mother in the room. So at that point although we had only had intercourse 10 days or so before my wife told him about it and she indeed had no contact; according to my father in law the gentleman then said she basically shouldn't hang around the hospital period. On the second day I saw my wife and saw how she wouldn't walk into her mother's room, I think she talked to her through a crack in the door. So the proper precautions were taken. But even then imagine someone was in the same lift as my wife and was carrying a radioactive implant? Or someone with an implant sat next to her on the bus? In fact, when our second child was being born, we were in hospital and a family member came to visit us who was undergoing radio therapy, and I remember my wife saying "she's just walked into a ward full of pregnant women". I would think that if there was any kind of connection then there would be a lot more restrictions on people receiving this kind of treatment, like they would have to stay in isolation, no visitors, etc. Anyway, do any of you think there could be a possible connection?

Thanks you so much for taking the time to give me your input.

Hello Dagi, following up on your explanation, I wanted to ask you about something I found on the Duchenneregistry website: "If you have no other affected family members, there is a 66% (or 2 in 3) chance that you are a carrier. Approximately 33% (or 1 in 3) of cases of Duchenne muscular dystrophy are caused by what are called new mutations. These are random changes to the genetic code in the dystrophin gene that happen in only one egg or sperm. That one egg or sperm could create an affected male; rarely, an affected female; or a carrier female child who could later have affected children." In other websites they refer more generally either to mutation happening in the mother's egg or to the developing embryo. The thing I don't understand here is how the change in the genetic code for dystrophin could happen in the sperm of the father (not just the grandfather) if the father only gives the child the Y chromosome and the dystrophin gene is on the X chromosome. I can understand that the mutation may have happened in the grandfather because he gives his daughter the X chromosome. She would then become a carrier and have a 50% chance of passing it on. Thank you for your time.

Thanks again Dagl1. He has a normal set of 23 pairs, 22 and X/Y. Obviously it would be better if it were not this x-linked disease. With limb girdle MD, the autosomal recessive type, people can have more or less normal lifespans. This has come completely out of the blue. He is our eldest son. His brother, who is only a few months old, appears totally normal. But the eldest did not suckle well from birth, did not move much, and also had a clubfoot (left side and operated successfully). For a long time, we have thought that his problems just came from the club foot, but he recently had a blood test with a very high CK which is what has prompted the genetic test for muscular dystrophies. From what you have said, at least I can console myself with the idea that if it is DMD it is very unlikely to have come from me (if I have understood your explanation correctly). As I am on the old side, for the father, this is one idea that has troubled me. And I do know of a girl who has Apert where it is clear that the mutation came from her father (who is not young either).

Thank you Dagl1. I don't really know much about genetics. What I mean is if father's chromosomes or his DNA can somehow get mixed up with the x chromosome inherited by the child. If it is Duchenne it is definitely the dystrophin gene which is on the x chromosome. There is another type called limb-girdle muscular dystrophy where the mutation is on chromosome 15, for example, it is autosomal recessive, I understand that in this case both our genes would come into play. It might possibly be limb girdle but at the moment it all points to DMD. As you can see, my knowledge about this field is quite limited. As you have said "it will be independent of the father's chromosomes" I think this more or less answers it. Can I ask what you mean by "assuming normal chromosome inheritance"? Thanks.

My son is being tested to see if he has this or another form of Muscular Dystrophy. I have read that it is an x-linked genetic disease, which is usually inherited from the mother but that spontaneous mutations can also happen, plus there is "germline mosaicism". I am familiar with a case of Apert Syndrome which is often caused by a spontaneous mutation in a certain chromosome (10 I think) and often due to the father. I wonder if anyone could tell me if given that Duchenne concerns the dystrophin gene, which is on the x chromosome, whether the father's genetic input could be somehow involved in Duchenne developing (if it were a spontaneous mutation). I have seen references to spontaneous mutations occurring through the grandfather/grandmother and being passed on to the mother and then the grandchild, but so far I haven't seen much information about the father. Can we assume that the X chromosome in the child is exactly as it should be in the mother? Obviously the tests will clear this up, but they may take quite a while. Thanks.