Concept explainers
a.
To determine: The possible method to handle the scenario in which an individual should contact the proband beforehand to explain the results and the implications of the results.
Introduction: A couple has undergone a prenatal test in which the young woman (proband) is found to have the sickle cell trait (Ss), and her partner does not have the sickle cell anemia (SS). The woman’s family has a family history of sickle cell anemia. Their prenatal tests indicate that the fetus is affected with sickle cell anemia (ss) and the only way it is possible is when the woman’s partner is not the father of the fetus.
b.
To determine: Whether it is appropriate to keep the information from the partner as he believes he is the father of the baby and the other problems related to this case.
Introduction: A couple has undergone a prenatal test in which the young woman (proband) is found to have the sickle cell trait (Ss), and her partner does not have the sickle cell anemia (SS). The woman’s family has a family history of sickle cell anemia. Their prenatal tests indicate that the fetus is affected with sickle cell anemia (ss) and the only way it is possible is when the woman’s partner is not the father of the fetus.
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Chapter 16 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
- Prader-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_forwardA young lady requested pre-marital genetic counselling because her sister had died in infancy of gangliosidosis, an autosomal recessive disease. What is the risk that this young lady has similarly affected offspring? What advice should be given?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_forward
- Phenylketonuria (PKU) is a human hereditary disease resulting from the inability of the body to process the chemical phenylalanine, which is contained in the protein we eat. PKU is manifest in early infancy and, if it remains untreated, generally leads to cognitive impairment. PKU is caused by a recessive allele with simple Mendelian inheritance. A couple intends to have children but consults a genetic counselor because the man has a sister with PKU and the woman has a brother with PKU. There are no other known cases in their families. They ask the genetic counselor to determine the probability that their first child will have PKU. What is this probability?arrow_forwardA proband female with an unidentified disease seeks the advice of a genetic counselor before starting a family. Based on the following data, the counselor constructs a pedigree encompassing three generations: (1) The maternal grandfather of the proband has the disease. (2) The mother of the proband is unaffected and is the youngest of five children, the three oldest being male. (3) The proband has an affected older sister, but the youngest siblings are unaffected twins (boy and girl). (4) All the individuals who have the disease have been revealed. Duplicate the counselors featarrow_forwardIn Section 12-1, Julie is concerned that she may develop breast cancer, but testing shows that she does not carry the rare high-risk BRCA1 and BRCA2 alleles. What if further testing showed that some of her aunts, her mother, and she carried a common low-risk allele for breast cancer. What would you recommend to Julie if you were her genetic counselor?arrow_forward
- As a physician, you deliver a baby with protruding heels and clenched fists with the second and fifth fingers over-lapping the third and fourth fingers. a. What genetic disorder do you suspect the baby has? b. How do you confirm your suspicion?arrow_forwardThe Joneses were referred to a clinical geneticist because their 6-month-old daughter was failing to grow adequately and was having recurrent infections. The geneticist took a detailed family history (which was uninformative) and a medical history of their daughter. He discovered that their daughter had a history of a constant cough and wheeze that was becoming progressively worse, had difficulty gaining weight (failure to thrive), and had an extensive history of yeast infection (thrush) in her mouth. The geneticist did a simple blood test to check their daughters white blood count and determined that she had severe combined immunodeficiency (SCID). The geneticist explained that SCID is an immune deficiency that causes a marked susceptibility to infections. The defining characteristic is usually a severe defect in both the T- and B-lymphocyte systems. This results in one or more infections within the first few months of life that are serious and may even be life-threatening. Based on the family history, it was possible that their daughter had inherited a mutant allele from each of them and therefore was homozygous for a gene that causes SCID. If so, each time the Joneses had a child, there would be a 25% chance that the child would have SCID. Prenatal testing is available to determine whether the developing fetus has SCID. If the Joneses want to be certain that their next child will not have SCID, what types of reproductive options do you think they have?arrow_forwardPedigree Analysis Is a Basic Method in Human Genetics Using the pedigree provided, answer the following questions. a. Is the proband male or female? b. Is the grandfather of the proband affected? c. How many siblings does the proband have, and where is he or she in the birth order?arrow_forward
- Familial retinoblastoma, a rare autosomal dominant defect, arose in a large family that had no prior history of the disease. Consider the following pedigree (the darkly colored symbols represent affected individuals): a. Circle the individual(s) in which the mutation most likely occurred. b. Is the person who is the source of the mutation affected by retinoblastoma? Justify your answer. c. Assuming that the mutant allele is fully penetrant, what is the chance that an affected individual will have an affected child?arrow_forwardPedigree Analysis Is a Basic Method in Human Genetic: What does OMIM stand for? What kinds of information are in this database?arrow_forwardPedigree analysis is a fundamental tool for investigating whether or not a trait is following a Mendelian pattern of inheritance. It can also be used to help identify individuals within a family who may be at risk for the trait. Adam and Sarah, a young couple of Eastern European Jewish ancestry, went to a genetic counselor because they were planning a family and wanted to know what their chances were for having a child with a genetic condition. The genetic counselor took a detailed family history from both of them and discovered several traits in their respective families. Sarahs maternal family history is suggestive of an autosomal dominant pattern of cancer predisposition to breast and ovarian cancer because of the young ages at which her mother and grandmother were diagnosed with their cancers. If a mutant allele that predisposed to breast and ovarian cancer was inherited in Sarahs family, she, her sister, and any of her own future children could be at risk for inheriting this mutation. The counselor told her that genetic testing is available that may help determine if this mutant allele is present in her family members. Adams paternal family history has a very strong pattern of early onset heart disease. An autosomal dominant condition known as familial hypercholesterolemia may be responsible for the large number of deaths from heart disease. As with hereditary breast and ovarian cancer, genetic testing is available to see if Adam carries the mutant allele. Testing will give the couple more information about the chances that their children could inherit this mutation. Adam had a first cousin who died from Tay-Sachs disease (TSD), a fatal autosomal recessive condition most commonly found in people of Eastern European Jewish descent. Because TSD is a recessively inherited disorder, both of his cousins parents must have been heterozygous carriers of the mutant allele. If that is the case, Adams father could be a carrier as well. If Adams father carries the mutant TSD allele, it is possible that Adam inherited this mutation. Because Sarah is also of Eastern European Jewish ancestry, she could also be a carrier of the gene, even though no one in her family has been affected with TSD. If Adam and Sarah are both carriers, each of their children would have a 25% chance of being afflicted with TSD. A simple blood test performed on both Sarah and Adam could determine whether they are carriers of this mutation. Would you decide to have a child if the test results said that you carry the mutation for breast and ovarian cancer? The heart disease mutation? The TSD mutation? The heart disease and the mutant alleles?arrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning