Human Genetics: Chapter 20

Which of the following would provide the longest lasting treatment for Leber's congenital amaurosis II?

injecting adeno-associated virus carrying a wild type version of the RPE65 gene into affected cells of the retina

Germline gene therapy would correct a genetic defect in

an affected individual and all of his or her descendants.

The field of genetic counseling began when the term was coined

in 1947, to help physicians explain inherited diseases to their patients.

Reginald receives a stem cell transplant to treat a blood cancer, multiple myeloma. His treatment is an example of

somatic gene therapy.

Rita has been diagnosed with Her2 breast cancer, and is prescribed Herceptin. The approach of basing a drug prescribing decision on the results of a single-gene test is called


Unlike cholesterol checks and chest x-rays, the results of genetic tests may have repercussions to family members who share genotypes that can affect health.


Which of the following might a genetic counselor do as part of her job?

explain the inheritance of a specific disorder in a family, evaluate risks for relatives, and advise on genetic testing

One of the most important types of information that a patient can bring to an initial appointment with a genetic counselor is

the family health history, extending to second degree relatives.

A serious limitation of using a retrovirus as a vector for gene therapy is that

the retrovirus may insert into a proto-oncogene, causing cancer.

A genetic counselor might discuss assisted reproductive technologies with a couple who wish to

avoid one parent's passing on a disease-causing allele to a child.

A nasal spray for cystic fibrosis patients, which contains adenovirus particles carrying a normal human CFTR gene, is an example of

in vivo gene therapy.

Newborn screening using tandem mass spectrometry identifies certain single-gene disorders by detecting

an unusual metabolite or metabolic imbalance.

Maxwell needs to take an anti-depressant drug. He enrolls in a clinical trial to detect genetic variants and gene expression profiles associated with response to various drugs. This approach to selecting a therapeutic drug is called


The defect in Canavan disease that causes the symptoms is

the stripping of the lipid layer from brain neurons.

Diagnosis of hereditary hemochromatosis cannot be based on the results of a genetic test alone because

the disease is non penetrant.

Many children born with ornithine transcarbamylase deficiency (OTC) die within seventy-two hours of birth. Jesse Gelsinger was not diagnosed with OTC until he was two because _______ and therefore his symptoms were milder.

he was a mosaic

Enzyme replacement therapy treats

the phenotype.

Which of the following is a vector used to deliver genes in human gene therapy?

adeno-associated virus

Nonheritable gene therapy is performed on _______ cells.


Introducing a gene in a liposome to carry DNA across the plasma membrane is a(n) _______ gene therapy.

in vivo

Performing gene therapy on somatic cells removed from the body and then returned to the body is called _______ gene therapy.

ex vivo

Tyrone has Gaucher disease. He receives recombinant glucocerebrosidase every other week in an infusion to prevent the symptoms. This treatment is an example of

enzyme replacement therapy.

Adenosine deaminase (ADA) deficiency results in

severe combined immune deficiency.

Preconception comprehensive carrier screening" is a battery of tests that detect disorders that arise later in life.


Nondirective genetic counseling

offers options but not opinions.

Newborn screening reveals that newborn Jessica has inherited PKU. Her parents are distraught at the diagnosis, but a nutritionist explains that Jessica can be treated, right away. The treatment for PKU is


Patients-in-waiting" are false positives whose newborn screening reveals disease markers, but never develop the predicted symptoms.


Macy has BRCA1 breast cancer. Her sister Philene is healthy, but wants to know if she has inherited the BRCA1 mutation that could make her develop cancer. She is a candidate for a

predisposition test.

One of the first applications of pharmacogenetics in prescribing drugs is for

Warfarin, a blood thinner.

Which is an example of a germline gene therapy?

a transgenic plant or animal

Sheree is referred to a genetic counselor because a cystic fibrosis (CF) test done as a routine part of her prenatal care indicated that she is a carrier of the most common mutant allele. Sheree is stunned, because no one in her family has the disease. Sh

explain autosomal recessive inheritance and suggest that Sheree's husband be tested for CF.

Genetic counseling to help patients with Huntington disease in their families decide if they wish to be tested generally

takes several months.

The Genetic Testing Registry of the U.S. National Institutes of Health acts as a clearinghouse to provide information on genetic tests.


A test offered on the Web by a direct-to-consumer genetic testing company genotypes a gene for ability to taste bitter substances. This test is not regulated by the Clinical Laboratory Improvement Amendments (CLIA) because

the test provides information, not a diagnosis.

Aminoglycosides may be useful in treating genetic disease by nonsense suppression.


A patient received bone marrow modified by an adeno-associated virus (AAV) carrying the human gene that encodes an enzyme her body could not make. This is an example of

somatic gene therapy.

Leber congenital amaurosis type 2 has been successfully treated using gene therapy.


Using gene therapy to correct ornithine transcarbamylase deficiency (OTC) would prevent buildup of _________ in the blood.


Pharmacological chaperone therapy

restores proper folding to a misfolded protein.

The species naturally affected by Leber's congenital amaurosis II that led to development of gene therapy is

a breed of dog.

Which of the following would provide the longest lasting treatment for adenosine deaminase (ADA) deficiency?

receiving white blood cells genetically modified to carry functional ADA genes

The liver is a good candidate for gene therapy because

NOT: it has only one function.
NOT: it is both an organ and a gland

A retrovirus is given a functional version of a gene that a patient lacks and used to infect the patient's skin cells growing in culture. Skin is grown from the altered cells and grafted onto the patient. If all works well, the graft will

be accepted and secrete the inserted gene's protein product.

A difficulty in developing gene therapy for diseases of the nervous system is that

NOT: neurons are located throughout the body.

Gene therapy for Leber's congenital amaurosis II consists of

injecting wild type alleles of the RPE64 gene into affected cells of the retina.

Introducing a gene in a liposome through holes bored into the skull is a(n) _______ gene therapy.

NOT: in situ