Carrier Of Fragile X Her Mother example essay topic

Biol 100 Lab Report 2 Gerard Chretien November 12, 2001 I. According to the pedigree for the fragile X syndrome in Mrs. S.'s family it shows that her deceased father neither had nor was a carrier of fragile X. Her mother is a carrier and her uncle is likely to have the disease. She also had a sibling that was either stillborn or aborted. It is possible that this sibling had abnormal chromosomes also, which could be the reason the pregnancy did not reach full term. II. a.

Jane should be advised that her children have a 50% chance of inheriting the gene. Due to the fact that the disease is a x-linked recessive trait, if Jane has a son and he inherits the affected chromosome he will have the disease and will most likely be a more severe case then in previous generations. If she has daughter she will have 50% chance of being a carrier and if so will then likely pass the gene onto future generations. Carol should receive the same counseling given to Jane and should also be advised to have her daughter, who is already showing signs of a mental handicap, tested for fragile x-syndrome.

Both women might want prenatal testing done to determine if the fetus carries the gene. Both women should know that with proper therapy, including medication, education and support persons with fragile x-syndrome could make improvements to their condition. b. Carol's daughter is under the same risks as her mother and should be given the same advice. Genetic testing would be advised for her future husband to clarify if he also is a carrier. c. It's possible that Mrs. S's grandfather had a "pre-mutated" form of the disease, which would explain the reason of Mrs. S's brother having a more severe form of the disease. The grandmother could have also been a carrier with little or no mental retardation. d.

If Mrs. S's grandmother was a carrier and passed the mutant allele to the son he would have had the disease, but would most likely be less severe than that of Mrs. S's brother or son.. We know that fragile x-syndrome is a chromosomal abnormality which is inherited as X-linked recessive. We also know that it is a genetic defect caused by excessive repetitions of the CGG triplet that expands with each generation as it's passed down. If we assume Mrs. S's uncle had fragile x-syndrome and he inherited from his mother that would mean that his genotype is showing the genetic imprinting from his mother's chromosomes rather than his fathers.

Because the fragile x gene expands and in return produces more severe affects as it is passed down through each generation, we can safely assume that he would have milder symptoms of the disease then that of Mrs. S's brother and son..