Chapter 24: Medical Genetics

haploinsufficiency

A dominant genetic disorder can be caused by ______, a situation where one functional copy of an allele is not sufficient to produce a normal phenotype.

Thousands

Approximately how many human diseases have a genetic basis?

therapy

Gene __________________is the introduction of cloned genes into somatic cells to treat disease.

B-cell acute lymphoblastic leukemia Non-Hodgkin lymphoma

Gene therapies were approved by the FDA in 2017 for which of the following diseases?

individual population

Genetic testing is used to determine whether a(n) ______ has a disease-causing gene, while genetic screening is used to determine how frequently the gene is found in a(n) ______.

ADA immune

If both copies of the ______________gene are defective, deoxyadenosine accumulates within the individual, which can lead to a severely compromised _____________system.

ADA immune

If both copies of the ____________gene are defective, deoxyadenosine accumulates within the individual, which can lead to a severely compromised ___________system.

single-nucleotide polymorphisms (SNPs)

In a genome-wide association study, the goal is to identify ______ which show a significantly different frequency between a control group and a group of individuals affected by a specific disease.

encodes a target protein with a different shape that will not effectively bind to the drug would slow transport of the drug from the digestive system to the bloodstream would cause faster metabolism of the drug than in other patients

In determining the proper dose of a drug to give a patient, which factors need to be considered? Whether the patient has a gene that ______.

Viruses used in gene transfer cannot replicate within target cells.

In which way are viruses used for gene transfer different from their wild-type counterparts?

identification of the genes that play a role in the development of a specific type of cancer

Molecular profiling is ______.

founder

The first individual who carried a disease called allele is called a ______.

Manhattan plot

Which represents a way to visualize the results of a genome-wide association study?

transplant ADA, adenosine deaminase, or adenosinedeaminase therapy

A patient with ADA deficiency can be treated with a bone marrow______________ , injections of purified ____________enzyme coupled with polyethylene glycol, or gene ______________.

founder

A single individual who first had a disease-causing allele is called a ____________.

locus heterogeneity

A situation where a disease may be caused by mutations in two or more different genes is called ______.

ex vivo

A technique where genetic manipulations occur outside of the body, and then the products are reintroduced into the body is called a(n) ____________ ____________approach.

HapMap

A worldwide effort to identify human genetic variation observed for SNPs and other variants is called the International Project ___________.

obtaining fetal cells in a sample from the fluid surrounding the fetus

Amniocentesis is a procedure for ______.

haplotype

Consider the accompanying figure showing four variable sites along a chromosome that can have any of three different versions, A, B or C, at each site. For this individual, the listing 1C 2C 3C 4A is a ______.

haplotype

The linkage of alleles or molecular markers along a single chromosome is called a ______.

Inherited diseases involving a single gene abnormality

What types of human diseases are the most straightforward targets for gene therapy?

gain-of-function

A dominant genetic disorder can be caused by a ______ mutation, where the product of an altered gene gains a new or abnormal function.

amniocentesis

A method for obtaining fetal cells in a sample of the fluid surrounding the fetus is called ______.

association study

An examination of the genomes of many different individuals to determine if a specific genetic variant is associated with a human disease is called a genome-wide _______________ ______________.

Fetus <> Amniocentesis and karyotyping to detect chromosomal abnormalities Newborn baby <> Test for excess phenylalanine demonstrating phenylketonuria (PKU) Adult <> Test for carrier status if one belongs to a family with a history of a specific disease

Match the life stage on the left to the type of screening on the right that would be used to detect a genetic disease.

ADA

One form of severe combined immune deficiency disease (SCID) is caused by inheriting two defective copies of the ______ gene that encodes an enzyme involved in purine metabolism crucial to the maintenance of healthy immune system cells.

therapy preventative measure medication

Personalized medicine can be used to select a ______.

study of genetic variations that cause differing responses to drugs

Pharmacogenetics is the ______.

1. A gene of interest is placed into a viral vector. 2. The virus is taken up by cells via endocytosis. 3. The viral coat disassembles, releasing the viral genome into the cytosol. 4. The genome is reverse-transcribed into DNA. 5. The viral DNA is imported into the nucleus. 6. The gene of interest is integrated into a chromosome of the target cell by recombination.

Place the steps by which a cloned gene is transferred into human cells using a retroviral technique in order, with the first step at the top.

Muscular Cancer Blood Metabolic Lung

Select the types of diseases that are being investigated as potential targets for gene therapy.

PEG-ADA treatment Gene therapy Bone marrow transplant

Select treatments for patients with adenosine deaminase (ADA) deficiency.

Blood

Sickle cell disease, hemophilia, and SCID are all diseases for which gene therapy may be useful. What type of disease are these?

Carriers often show reduced activity for the enzyme encoded by the allele.

Suppose a disease-causing allele shows autosomal recessive inheritance. How could a carrier of this disease-causing allele be identified?

1. Homozygous recessive 2. Heterozygous 3. Homozygous dominant

Tay-Sachs disease is inherited with an autosomal recessive allele that leads to a defect in the enzyme hexosaminidase A. When cells are collected from patients, cells with different genotypes exhibit different amounts of enzymatic activity. Rank the amount of enzymatic activity that would be detected in a biochemical assay on cells from patients of these genotypes, with the genotype producing the LEAST amount of enzymatic activity on top.

single-nucleotide polymorphisms

The International HapMap Project is an effort to identify differences in human DNA sequences by identifying ______.

haplotypes

The accompanying figure shows four variable sites, linked together along a chromosome. Each site can have any of three different versions, A, B or C. The symbols 1A 2B 3B 4C and 1C 2C 3C 4A indicate ______ for the individual shown.

C

The accompanying pedigree shows the inheritance of Huntington disease with filled symbols and also indicates which combination of four possible forms (A, B C, D) of a molecular marker called G8 that the person has inherited. Although there are some exceptions, the inheritance of Huntington disease is most closely associated with which form of the G8 marker in this pedigree?

BB with Huntington disease

The accompanying pedigree shows the inheritance of Huntington disease with filled symbols and also indicates which combination of four possible forms (A, B C, D) of a molecular marker called G8 that the person has inherited. What is the one possible phenotype and marker combination that is missing among the children of the couple surrounded by the circle?

genome-wide association

The data shown in the figure represent the results of a ______ study for human chromosomes 1 through 12.

locus heterogeneity

The disease hemophilia is caused by a deficiency in any one of three blood clotting factors. Two of these factors are encoded by genes on the X chromosome and the other clotting factor gene is located on an autosome. Since mutations in more than one gene can cause hemophilia, this represents ______.

genome-wide association

The goal of a ______ study is to find a relationship between one or more single-nucleotide polymorphisms (SNPs) and a disease or other human trait.

molecular profiling

The process of identifying the genes that play a role in the development of a specific type of cancer is called ______.

pharmacogenetics

The study of genetic variations that cause differing responses to drugs is called ______.

personalized medicine

The use of information about a patient's genotype in order to select a medication or therapy that is specifically suited to the patient is called _____________ ________________.

single-nucleotide polymorphisms (SNPs)

To conduct a genome-wide association study, the ______ of a large group of individuals who are afflicted with the same disease are compared to those of a large group of people without the disease.

testing screening

To study the distribution of disease-causing genes, genetic ______ refers to determining if an individual carries the faulty gene, while genetic ______ relates to assessing the presence of the gene throughout a population.

False

True or false: A disease with a genetic origin in a mouse is unlikely to be an inherited disease in humans.

True

True or false: Comparing someone with a genetic disease to another person in the general population, the person with the disease is more likely to have a family member with the same disease.

True

True or false: Genetic diseases often show a specific age of onset.

immune

Two gene therapies that target _________________ system cells were approved in 2017, to treat B-cell acute lymphoblastic leukemia and non-Hodgkin lymphoma.

simple Mendelian inheritance patterns

When a defect in a single gene causes a human disease, the mutant gene often follows ______.

ex vivo

When an experiment or treatment involves genetic manipulation outside of the body, followed by reintroduction into the body, it is called an ______ approach.

Drug transport Drug metabolism Ability of drug to affect its target protein

Which aspects of drug interaction within the body are affected by genetic variation in humans?

A haploid genotype showing linkage of alleles or molecular markers along a single chromosome

Which best describes a haplotype?

One family in the neighborhood has one parent and several children with severe hearing loss. No one in any of the other nearby families has deafness. Someone with a diagnosis of retinitis pigmentosa has learned that there are family members in the preceding three generations who had the disease. Nephroblastoma is a cancer of the kidney that typically develops in children and is only rarely found in adults.

Which observations are consistent with a disease having a genetic basis?

Test for excess phenylalanine indicating phenylketonuria (PKU)

Which of these is a common example of widespread genetic screening of newborns to identify certain disorders?

Dominant-negative

Which type of mutation causes a dominant genetic disorder through the production of an altered protein that works against the action of the normal protein?