013-300 Autismo e Genetica parte 12 (volume terzo)


Uploaded by RotoloGiuseppe on 25.01.2011

Transcript:
The FMR1 gene is on chromosome X. This gene normally has the triplet of nitrogen bases or nucleotides CGG is repeated few times.
Many people with fragile X syndrome have an increase in the repetition of the triplet of nucleotides cytosine, guanine, guanine (CGG). The repetition may be more or less extensive.
There are signs, in some cases, more than 200 repetitions of the triplet. In the presence of fragile X chromosome, males often have more severe symptoms than females.
The X chromosome of males is only provided dall'ovocita mother. Females have two X chromosomes instead, one from a mother from the father.
Females have two X chromosomes then available to find a better balance molecules.
Females have mild symptoms or may simply be healthy carriers
We add some details about the genetic sitazione women. We have said that women can simply be healthy carriers or have mild symptoms
That may be carriers of 50% of X chromosomes damaged and 50% of healthy X chromosomes. The woman will then have 50% chance of fertilizing an ovum and a healthy 50% chance of fertilizing an egg with a damaged X chromosome
The information on the risks of birth control, can be provided to parents by the obstetrician or the pre-pregnancy counseling centers
This information is particularly sought after by parents who already have a year autistic son
Where Parents already have an autistic son, want to know how likely the second child might be autistic
To be more precise what is the impact of a second child with autism
The repetition in the gene FMR1è defined as normal when there are few CGG triplet cytosine, guanine, guanine. In this video, we have prepared, have represented a number of physiological, that is normal, CGG triplets
These triplets are represented, as already mentioned, within the FMR1 gene. The Genne conivolto FMR1 is in cases of X chromosomefragile
If you are having more than 200 repetitions you chromosomal damage evident. We will discuss a first sequence of triplets. And 'present in the blue cytosine, guanine in red 2
The three nitrogen bases or nucleotides, form the basic message guanine cytosine, guanine, CGG. This message is based CGG repeats physiologically, only a few times on the X chromosome, and in particular in FMR1 gene. You can see in the movie the normal sequence CGG-CGG-CGG-CGG-CGG
This sequence is present in the FMR1 gene. This sequence of bases nitrogen or nucleotides can also be seen in the DNA strand. DNA is found very often in the form of a double helix. To show more clearly the position of the CGG triplet we preferred to show only one propeller
You can see the strand of DNA sequence of the CGG triplets. In cases of fragile X CGG triplet is found in the DNA strand more than 200 times here for reasons we have only a few graphs triplets. It was found that the greater the number of CGG triplets within the FMR1 gene is the worst symptoms