Fragile x Assignment 4 Adam had one daughter (Beverly) when he was 25 years old,
ID: 142519 • Letter: F
Question
Fragile x Assignment 4 Adam had one daughter (Beverly) when he was 25 years old, another (Bonnie) when he was 27 years old, and a son (Brian) when he was 30. Bonnie has two sons and a daughter. Her first son (Charlie) has many developmental delays, and the pediatrician has done enzymes studies for specific biochemical disorders. All were negative. When Charlie was six years old, his maternal aunt (Adam's first daughter, Beverly) is 40 years old and pregnant. As part of prenatal diagnostic work, she has blood drawn for genetic disorders, and an amniocentesis is performed. The amniocentesis is performed. The amniocentesis indicates she is pregnant with a normal girl, However, Beverly's blood work reveals that she is a fragile X syndrome permutation carrier status. When Beverly tells Bonnie about this, Bonnie informs her pediatrician about Beverly permutation carrier status. The pediatrician sends Charlie for testing, and he found to have more than 1000 CGG trinucleotide repeat sequences in his FMR1 gene alleles with 90% methylation, giving him a diagnosis of fragile X syndrome. 1. 2. 3. 4. 5. What is the risks do Bonnie's children have for permutation carrier status? What risk do Beverly children have for permutation carrier status or for FXS What risks do Brian's children have for permutation carrier status or for FXS Why is Adam unaffected? What is the risk for Adam's mutation status to change to a full mutation? Explain your responseExplanation / Answer
Please find the answers below:
Answer 1: According to the information, Adam is affected with fragile X syndrome suggesting his only X-chromosome contains the anomality. Thus, this single X chromosome will be transferred to all of his kids except his son. Thus, both the daughters, Beverly and Bonnie are carriers of this disease, having 50% chances of having the disorder. However, since females are homozygous for X-chromosome, there are 0% chances that either of these sisters will be affected with the disease, both Bonnie and Beverly. Further, these daughters will be capable of transferring this gene to their kids, thus, the chances being reduced to half agian i.e. 50/2 or 25% each.
Answer 2: As for Beverely again, the chances of transferring this affected X-chromosome will be same as Bonnie, i.e. 25%.
Answer 3: Since Brian has acquired only Y-chromosome from his father, he is not a carrier of fragile-X chromosome, hence will never transfer the disease to his offsprings.
Answer 4: Adam seems to be a carrier of fragile X chromosome but still is unaffected from the disease. It is a very well known fact that the aetiology of this syndrome depends upon the number of mutated sites in the gene of fragile X chromosome. It seems that Adam has very few mutations in this gene for being pathologically implicated, hence unaffected.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.