Genetics & Diagnosis of Fragile X Syndrome
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Genetics & Diagnosis of Fragile X Syndrome


Fragile X syndrome is caused by an
unusual gene. This particular gene is on the X chromosome. That means that
girls have two copies of it and girls have a single copy. Everybody has this gene and everybody has a typical repeating pattern of chemicals in the
gene. But, in people who’ve got the condition, that’s disrupted and elongated.
This stops the gene working. If there’s a change in that fragile X gene in a boy, you can see the full effect of it. In a girl, she will only use one copy
of the gene in each of her cells and switch off the second copy. That
means that it can mask the effects to some extent, because fragile X syndrome
is due to a change on the X chromosome. It can be inherited and run in the
family. Women have two X chromosomes and if they have a change in one copy of the fragile X gene in one of those X chromosomes, they will have a 50/50 chance of passing that on to any child.
Actually, the inheritance and genetics is quite complex. So, everybody
needs to seek out information about their own individual situation in
genetics One should be considering fragile X syndrome in any individual with unexplained intellectual disability. In particular, but not necessarily, in
association with autistic-like features. It should be part of a routine
assessment battery undertaken by a
developmental pediatrician Fragile X Syndrome is diagnosed when somebody has a clinical suspicion about it and
arranges a test. The tests that we do nowadays looks at the gene in a lot of detail and tells us how big that stretching of the gene is and whether there’s the other chemical alteration that stops the gene working, which is methylation. So it’s a blood test to look directly at the gene that we do On the eighteenth month we had the diagnosis of fragile X syndrome. We hadn’t heard anything about it before, we were like “fragile what?” and then, you know, the
geneticist explained to us. We also need to test other people in
family who might be carriers or at risk of the condition. When someone’s diagnosed, they usually come and see a genetic doctor or genetic counselor and work out who in the family might need to be tested, as well. Blood was taken from all four of us, they said that they were going to check Susan I, being twins, but they felt sure that we couldn’t be identical because I was supposedly not
affected, whereas Susan was but when the tests came back, they proved that we were identical. At the time they didn’t really understand why that could be, but
now it’s something to do with X inactivation in women and I’m lucky. Diagnosis is important for a number of reasons. Firstly, the individual and their
family have a right to know why the person is experiencing these
developmental and psychological challenges. That goes a long way in
relieving the sense of uncertainty and facilitating the grief reaction which
happens for every individual and family following the release of a diagnosis. When Ramaiah was first diagnosed it’s
like, okay, that’s why he is the way he is There was quite a lot of stuff going on with him. Sometimes you think, oh gosh, you’re doing something wrong as a parent. What are we doing as parents? Are we putting him in the wrong
setting? All those questions come up but then you say, oh no, it’s none of those things. There is a reason. For the girls, obviously having that diagnosis it’s just really scary and you wonder what their lives
would be. You know, obviously at four years old and 18 months old ,you scroll
forward until they’re 40 and you’re longer there and etc and you worry, and you panic. You just start thinking about how to put a
structure in place for them. With Jason and Gary, once we were told there was a medical reason for them being the way they were It meant we didn’t have to give
excuses, we didn’t have to make excuses for Jason going like that [bites hand]. Because I’m a geneticist, the thing that I think it helps where this particularly
understanding who might be at risk in the family: who may be a carrier and thinking about planning further children, with that information to hand. We have a lot of information that we can give on individual strengths and needs profiles and that helps us to commence appropriate interventions, as
soon as possible, to prevent later challenges. Last, but certainly not least,
it allows individuals in the family to relate to an appropriate support network.
The group in this instance is the UK Fragile X Society. Diagnosis made sense because he wasn’t hitting his milestones he was quite late developmentally,
so it made sense. Also, it brought tons of other questions you know how are we going do this, what’s he gonna be like, what’s the potential? You know, how can we help him? You know, all sorts of questions. The diagnosis is one thing, but
then what I would kept hearing was all the negative side. I wasn’t hearing about
anything that he could do. Then I said, for me, just seeing little bits of progress made me think: maybe we could do something to make him progress further than what they’re telling us. He actually started to
progress socially first, and that just made me and, you know, you think actually he’s already beaten targets that people have said. So that gave me hope about, you know, we were doing the right thing. When you get that diagnosis it does lift a big onus off you. It helps you understand it a lot more and it makes you appreciate the kids. Because, I’m like, I’m gonna fill up here,
because it gives you that out Whereas before you think yeah they’re
gonna be you know like… You get all these kids now, if they were given a little bit of time and things like that, you’d see where they’re come from you’d probably understand them a lot more. There’s a light at the end of the tunnel

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