Concept explainers
Case summary:
A couple with European ancestry having the history of cystic fibrosis in the husband’s family. The husband is heterozygous for the
Characters in the case:
A couple and the genetic counselor.
Adequate information:
Both husband and wife are heterozygous for specific mutations and do not want to have a child homozygous for either mutation. They express their conviction while consulting with a genetic counselor.
To determine: the adequate suggestion provided by the genetic counselor to the couple.
Given information:
Both husband and wife are heterozygous for specific mutations and do not want to have a child homozygous for either of the mutation which leads to the risk of developing cystic fibrosis in the child.
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EBK ESSENTIALS OF GENETICS
- You are a genetic counselor, and your patient has asked to be tested to determine if she carries a gene that predisposes her to early-onset cancer. If your patient has this gene, there is a 50/50 chance that all of her siblings inherited the gene as well; there is also a 50/50 chance that it will be passed on to their offspring. Your patient is concerned about confidentiality and does not want anyone in her family to know she is being tested, including her identical twin sister. Your patient is tested and found to carry a mutant allele that gives her an 85% lifetime risk of developing breast cancer and a 60% lifetime risk of developing ovarian cancer. At the result-disclosure session, she once again reiterates that she does not want anyone in her family to know her test results. a. Knowing that a familial mutation is occurring in this family, what would be your next course of action in this case? b. Is it your duty to contact members of this family despite the request of your patient? Where do your obligations lie: with your patient or with the patients family? Would it be inappropriate to try to persuade the patient to share her results with her family members?arrow_forwardPrader-Willi syndrome is caused by a mutation in anautosomal maternally imprinted gene. Label the following statements as true or false, assuming that thetrait is 100% penetrant.a. Sons of affected males have a 50% chance of showing the syndrome.b. Daughters of affected males have a 50% chance ofshowing the syndrome.c. Sons of affected females have a 50% chance ofshowing the syndrome.d. Daughters of affected females have a 50% chanceof showing the syndrome.arrow_forwardWhat is preimplantation genetic testing? Give an example of a condition screened for? Do you agree with preimplantation screening and what are some of the ethical concerns surrounding the practice?arrow_forward
- Which of the examples of genetic testing below are prognostic tests? Which are diagnostic? (a) Individual sequencing (personal genomics) identifies a mutation associated with Alzheimer’s disease. (b) ASO testing determines that an individual is a carrier for the mutant b@globin allele (bS) found in sickle-cell anemia. (c) DNA sequencing of a breast tumor reveals mutations in the BRCA1 gene. (d) Genetic testing in a healthy teenager identifies an SNP correlated with autism. (e) An adult diagnosed with Asperger syndrome (AS) has a genetic test that reveals a SNP in the GABRB3 gene that is significantly more common in people with AS than the general population.arrow_forwardMany genetic counselors will not provide presymptomatic genetic testing for Huntington disease to people below the age of 18. Why are there concerns about offering this and many other genetic tests to minors? What types of presymptomatic genetic testing might be appropriate for minors?arrow_forwardPrader-Willi Syndrome (PWS) is caused by a mutation in an autosomal gene that is maternally imprinted. If a male is affected with PWS, each of his sons has a ["100%", "75%", "50%", "25%", "0%"] chance of being affected with PWS, and each of his daughters has a ["50%", "75%", "25%", "0%", "100%"] chance of being affected with PWS. Pick answers within quotation marks to fill in blanks.arrow_forward
- Pedigree Analysis Is a Basic Method in Human Genetic: What are the reasons that pedigree charts are used?arrow_forwardJames sees an online ad for an at-home genetic test that promises to deliver personalized nutritional advice based on an individuals genetic profile. The company can test for genetic variations, the advertisement states, that predispose individuals to developing health conditions such as heart disease and bone loss or that affect how they metabolize certain foods. If such variations are detected, the company can provide specific nutritional advice that will help counteract their effects. Always keen to take any steps available to ensure the best possible health for their family, James and his wife (Sally) decide that they both should be tested, as should their 11-year-old daughter (Patty). They order three kits. Once the kits arrive, the family members use cotton swabs to take cell samples from their cheeks and place the swabs in individually labeled envelopes. They mail the envelopes back to the company, along with completed questionnaires regarding their diets. Four weeks later, they receive three individual reports detailing the test results and providing extensive guidelines about what foods they should eat. Among the results is the finding that James has a particular allele in a gene that may make him vulnerable to the presence of free radicals in his cells. The report suggests that he increase his intake of antioxidants, such as vitamins C and E, and highlights a number of foods that are rich in those vitamins. The tests also show that Sally has several genetic variations that indicate that she may be at risk for elevated bone loss. The report recommends that she try to minimize this possibility by increasing her intake of calcium and vitamin D and lists a number of foods she could emphasize in her diet. Finally, the report shows that Patty has a genetic variation that may mean that she has a lowered ability to metabolize saturated fats, putting her at risk for developing heart disease. The report points to ways in which she can lower her intake of saturated fats and lists various types of foods that would be beneficial for her. A number of companies now offer genetic-testing services, promising to deliver personalized nutritional or other advice based on peoples genetic profiles. Generally, these tests fall into two different categories, with individual companies offering unique combinations of the two. The first type of test detects alleles of known genes that encode proteins that play an established role in, for example, counteracting free radicals in cells or in building up bone. In such cases, it is easy to see why individuals carrying alleles that may encode proteins with lower levels of activity may be more vulnerable to free radicals or more susceptible to bone loss. A second type of test examines genetic variations that may have no clear biological significance (i.e., they may not occur within a gene or may not have a detectable effect on gene activity) but have been shown to have a statistically significant correlation with a disease or a particular physiological condition. For example, a variation may frequently be detected in individuals with heart disease even though the reason for the correlation between the variation and the disease may be entirely mysterious. Do James and Sally have any guarantees that the tests and recommendations are scientifically valid?arrow_forwardJames sees an online ad for an at-home genetic test that promises to deliver personalized nutritional advice based on an individuals genetic profile. The company can test for genetic variations, the advertisement states, that predispose individuals to developing health conditions such as heart disease and bone loss or that affect how they metabolize certain foods. If such variations are detected, the company can provide specific nutritional advice that will help counteract their effects. Always keen to take any steps available to ensure the best possible health for their family, James and his wife (Sally) decide that they both should be tested, as should their 11-year-old daughter (Patty). They order three kits. Once the kits arrive, the family members use cotton swabs to take cell samples from their cheeks and place the swabs in individually labeled envelopes. They mail the envelopes back to the company, along with completed questionnaires regarding their diets. Four weeks later, they receive three individual reports detailing the test results and providing extensive guidelines about what foods they should eat. Among the results is the finding that James has a particular allele in a gene that may make him vulnerable to the presence of free radicals in his cells. The report suggests that he increase his intake of antioxidants, such as vitamins C and E, and highlights a number of foods that are rich in those vitamins. The tests also show that Sally has several genetic variations that indicate that she may be at risk for elevated bone loss. The report recommends that she try to minimize this possibility by increasing her intake of calcium and vitamin D and lists a number of foods she could emphasize in her diet. Finally, the report shows that Patty has a genetic variation that may mean that she has a lowered ability to metabolize saturated fats, putting her at risk for developing heart disease. The report points to ways in which she can lower her intake of saturated fats and lists various types of foods that would be beneficial for her. A number of companies now offer genetic-testing services, promising to deliver personalized nutritional or other advice based on peoples genetic profiles. Generally, these tests fall into two different categories, with individual companies offering unique combinations of the two. The first type of test detects alleles of known genes that encode proteins that play an established role in, for example, counteracting free radicals in cells or in building up bone. In such cases, it is easy to see why individuals carrying alleles that may encode proteins with lower levels of activity may be more vulnerable to free radicals or more susceptible to bone loss. A second type of test examines genetic variations that may have no clear biological significance (i.e., they may not occur within a gene or may not have a detectable effect on gene activity) but have been shown to have a statistically significant correlation with a disease or a particular physiological condition. For example, a variation may frequently be detected in individuals with heart disease even though the reason for the correlation between the variation and the disease may be entirely mysterious. Do you think that companies should be allowed to market such tests directly to the public, or do you believe that only a physician should be able to order them?arrow_forward
- James sees an online ad for an at-home genetic test that promises to deliver personalized nutritional advice based on an individuals genetic profile. The company can test for genetic variations, the advertisement states, that predispose individuals to developing health conditions such as heart disease and bone loss or that affect how they metabolize certain foods. If such variations are detected, the company can provide specific nutritional advice that will help counteract their effects. Always keen to take any steps available to ensure the best possible health for their family, James and his wife (Sally) decide that they both should be tested, as should their 11-year-old daughter (Patty). They order three kits. Once the kits arrive, the family members use cotton swabs to take cell samples from their cheeks and place the swabs in individually labeled envelopes. They mail the envelopes back to the company, along with completed questionnaires regarding their diets. Four weeks later, they receive three individual reports detailing the test results and providing extensive guidelines about what foods they should eat. Among the results is the finding that James has a particular allele in a gene that may make him vulnerable to the presence of free radicals in his cells. The report suggests that he increase his intake of antioxidants, such as vitamins C and E, and highlights a number of foods that are rich in those vitamins. The tests also show that Sally has several genetic variations that indicate that she may be at risk for elevated bone loss. The report recommends that she try to minimize this possibility by increasing her intake of calcium and vitamin D and lists a number of foods she could emphasize in her diet. Finally, the report shows that Patty has a genetic variation that may mean that she has a lowered ability to metabolize saturated fats, putting her at risk for developing heart disease. The report points to ways in which she can lower her intake of saturated fats and lists various types of foods that would be beneficial for her. A number of companies now offer genetic-testing services, promising to deliver personalized nutritional or other advice based on peoples genetic profiles. Generally, these tests fall into two different categories, with individual companies offering unique combinations of the two. The first type of test detects alleles of known genes that encode proteins that play an established role in, for example, counteracting free radicals in cells or in building up bone. In such cases, it is easy to see why individuals carrying alleles that may encode proteins with lower levels of activity may be more vulnerable to free radicals or more susceptible to bone loss. A second type of test examines genetic variations that may have no clear biological significance (i.e., they may not occur within a gene or may not have a detectable effect on gene activity) but have been shown to have a statistically significant correlation with a disease or a particular physiological condition. For example, a variation may frequently be detected in individuals with heart disease even though the reason for the correlation between the variation and the disease may be entirely mysterious. Do you think parents should be able to order such a test for their children? What if the test indicates that a child is at risk for a disease for which there is no known cure?arrow_forwardJames sees an online ad for an at-home genetic test that promises to deliver personalized nutritional advice based on an individuals genetic profile. The company can test for genetic variations, the advertisement states, that predispose individuals to developing health conditions such as heart disease and bone loss or that affect how they metabolize certain foods. If such variations are detected, the company can provide specific nutritional advice that will help counteract their effects. Always keen to take any steps available to ensure the best possible health for their family, James and his wife (Sally) decide that they both should be tested, as should their 11-year-old daughter (Patty). They order three kits. Once the kits arrive, the family members use cotton swabs to take cell samples from their cheeks and place the swabs in individually labeled envelopes. They mail the envelopes back to the company, along with completed questionnaires regarding their diets. Four weeks later, they receive three individual reports detailing the test results and providing extensive guidelines about what foods they should eat. Among the results is the finding that James has a particular allele in a gene that may make him vulnerable to the presence of free radicals in his cells. The report suggests that he increase his intake of antioxidants, such as vitamins C and E, and highlights a number of foods that are rich in those vitamins. The tests also show that Sally has several genetic variations that indicate that she may be at risk for elevated bone loss. The report recommends that she try to minimize this possibility by increasing her intake of calcium and vitamin D and lists a number of foods she could emphasize in her diet. Finally, the report shows that Patty has a genetic variation that may mean that she has a lowered ability to metabolize saturated fats, putting her at risk for developing heart disease. The report points to ways in which she can lower her intake of saturated fats and lists various types of foods that would be beneficial for her. A number of companies now offer genetic-testing services, promising to deliver personalized nutritional or other advice based on peoples genetic profiles. Generally, these tests fall into two different categories, with individual companies offering unique combinations of the two. The first type of test detects alleles of known genes that encode proteins that play an established role in, for example, counteracting free radicals in cells or in building up bone. In such cases, it is easy to see why individuals carrying alleles that may encode proteins with lower levels of activity may be more vulnerable to free radicals or more susceptible to bone loss. A second type of test examines genetic variations that may have no clear biological significance (i.e., they may not occur within a gene or may not have a detectable effect on gene activity) but have been shown to have a statistically significant correlation with a disease or a particular physiological condition. For example, a variation may frequently be detected in individuals with heart disease even though the reason for the correlation between the variation and the disease may be entirely mysterious. What kinds of regulations, if any, should be in place to ensure that the results of these tests are not abused?arrow_forwardPedigree Analysis Is a Basic Method in Human Genetic: What does OMIM stand for? What kinds of information are in this database?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning