It should be known this information was provided from
a researcher in the field of cystic fibrosis.


--- Terry Geiger <tegeiger@...> wrote:
> Here are thoughts on the 5T allele,
>
> The 5T allele has had a lot of press recently (and
> rightly so) and it’s important to know what all the
> fuss is about. There are two quite distinct features
> of the 5T allele.
>
> Firstly, it can have a role as a mutation modifier.
> Going back to R117H, this mutation can be on the
> same
> chromosome as a 5T allele or a 7T allele. When R117H
> is associated with 5T, it behaves more or less like
> a
> cystic fibrosis mutation (although generally a
> milder
> one). But when R117H is associated with a 7T allele,
> it is much less harmful. Not completely benign, but
> generally speaking, you would rather have the 7T
> version. The trouble is, it has lousy ‘predictive
> value’, because the two groups overlap in severity.
> [It must be understood that we are talking about the
> scenario where there is a typical cystic fibrosis
> mutation such as DeltaF508 on one chromosome, and
> the
> R117H (with either 5T or 7T) on the other.
> Secondly, it can have a role as a
> partially-penetrant
> mutation. Sorry about the terminology; it means that
> sometimes it behaves like a mutation and sometimes
> it
> doesn’t! In this case, we are talking about a 5T
> allele being on the opposite chromosome to DeltaF508
> (or other typical cystic fibrosis mutation). In
> other
> words, you have DeltaF508 on one of your chromosome
> 7s
> and a 5T allele on the other. Now, DeltaF508 has
> wrecked one of your CFTR genes completely, but what
> of
> the other one? If the 5T allele has not had too much
> of an effect, you might be OK, but remember that it
> does interfere with splicing. The bottom line is
> that
> the DeltaF508/5T genotype is associated with a
> number
> of presentations - it is seen in CBAVD,
> bronchiectasis
> and so on (but not ‘classic’ Cystic Fibrosis).
> Again,
> it’s a lousy predictor; if you picked up (by
> screening, for instance) an individual with
> DeltaF508
> and 5T, you would not really be able to say how that
> person would present clinically.
>
> A final note on the 5T allele. There has been some
> fuss recently (in the US) about women being offered
> prenatal diagnosis for the 5T allele. For example,
> one
> parent has DeltaF508 and the other has 5T and they
> are
> therefore at risk of having a child who is
> DeltaF508/5T. Or alternatively, both parent have
> been
> found to carry 5T and are at risk of having a child
> who is 5T/5T. Prenatal diagnoses and even
> terminations
> have been offered on the basis of finding 5T alleles
> (and the lawyers are queuing up, I suspect!).
>
> I suspect this has arisen from inappropriate use of
> a
> test in which the manufacturer describes the 5T as a
> mutation and inexperienced users of the kit have
> interpreted this as being as severe or significant
> as
> DeltaF508, for example. This is certainly a
> difficult
> area and one in which there is still much to be
> discovered.
>
> I hope this helps,
>
> Terry
>
> --- runthefox65 <runthefox65@...> wrote:
> > Hi, I am replying because my fiancee and i were
> > kinda thrown into
> > the same deal. I am curious to know what your
> > symptoms are.
> > Normally if one has the 5T allele mutation it is
> > directly linked to
> > pancreatic insuffiency. My fiancee has no known
> > history in his
> > family of cf but he has mutation of the delta F508
> > at the 5T
> > allele. He has no lung disease and infertility is
> > out too since we
> > have a daughter. His case is rare and we are
> doing
> > most of the
> > research ourselves. Maybe we can compare notes?
> > Anyway good luck
> > and best wishes that your husband is mutation
> free!\
> >
> > tiffany
> > --- In cysticfibrosissupport@yahoogroups.com, "ask
> > me nicely"
> > <hl_n_poole@h...> wrote:
> > > Hello,
> > >
> > > I was just tested for CF gene. I came back
> > Negative for CF gene
> > but
> > > positive for a mutation. Something about the
> 5th
> > allele. They
> > are
> > > now testing my hubby. They have stopped our
> > infertility treatment
> > > because of this. My questions are if i have a
> > mutation and if dh
> > > comes back pos. for CF could we pass to a child?
>
> > And what if he
> > is
> > > also neg. but pos. for a mutation could we pass
> to
> > a child. I
> > guess
> > > basically my question is what does it take to
> pass
> > to a child?
> > > thanks in advance,
> > > Nicole
> >
> >
>
>
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