Genetics

A patient with a fractured elbow in the emergency department states that he needs morphine for pain rather than codeine because the last time he had a painful injury, codeine was not effective in managing his pain. What is the nurse's best response or action?

communicate info to admitting physician

A 42 year-old expectant mother is considering chorionic villous sampling for this pregnancy to determine if this baby is affected by a genetic syndrome. The nurse has strong personal feelings about the issue but provides the patient information and then tells the patient "you must make the decision yourself." This nurse has provided counseling in a(n) ________________ manner.

nondirective

A woman whose hemoglobin S levels are less than 1% has a brother with sickle cell disease and both parents have been diagnosed as carriers for the disorder. She asks what her risks are of having a child with sickle cell disease. What is the best response?

"Because you do not have the trait, you cannot have a child with sickle cell disease regardless of your partner's sickle cell status."

A 48-year-old woman reports that her 50-year-old brother has severe bipolar disorder, and she is concerned that her two teenage daughters may be predisposed to the problem. She has no manic or depressive symptoms. How should you respond to her concerns?

"If the girls' father also has no symptoms of the disorder, your daughters have the same risk as the general population."

A patient in the U.S. is being seen for follow up counseling regarding his test results, which reveal that he has a genetic mutation that increases his risk for colon cancer. The patient says he does not want any of his family to know that he carries a genetic mutation. What should his health-care providers tell him?

"It is not required that you tell anyone about this result; however, because your siblings and children may also be at risk for colon cancer, you should think about how this information might help them."

A 21-year-old woman who has two brothers with Duchenne muscular dystrophy asks whether carrier status testing is appropriate for her. What is the best response?

"Testing could be beneficial because your risk for being a carrier is approximately 50%."

A man with syndactyly, an autosomal dominant condition, has one child who also has syndactyly. His unaffected wife states "Since the risk for having a child with this problem is 50% and our first child has the problem, the next child will not be affected." What is the best response to this statement?

"That is not quite true because the risk is 50% with each pregnancy, so all future children you have would have a 50% risk.

A man and his sister are both affected with a mitochondrial disorder. Because the sister has two children who also have the disorder, the man is concerned about the possibility of also having children with the disorder. What is the estimated risk for each pregnancy of this man producing a child with the same mitochondrial disorder that he has if his female partner does not have a mitochondrial disorder?

0%

What are the expected expressed blood types of children born to a mother who is B/B for blood type and a father who is A/O for blood type?

0% A, 50% AB, 50% B, 0% O

A girl of normal stature is born to two parents with achondroplasia who have very short stature, especially disproportionately short arms and legs. What is the probability (by Punnett Square analysis) that any pregnancy this girl eventually has will result in the birth of an infant with achondroplasia if her partner also has normal stature?

0/4

When constructing a pedigree around a specific health problem, what is the minimal number of generations needed to accurately assess the presence or absence of a genetic factor in disease development?

3

What is the risk for a person to inherit an autosomal-dominant genetic disease-causing allele from a parent who is heterozygous if the disorder has a penetrance factor of 75%?

50%

What is the relationship among genes, DNA, and proteins?

A gene is a section of DNA that provides the directions for synthesizing a specific protein

What percentage of bases in a stretch of double-stranded DNA that contains 10% guanine (G) bases would be adenine (A)?

40%

Which chromosome number represents the euploid state for normal human somatic cells?

46

The process of spermatogenesis produces __________ spermatid(s), while the process of oogenesis produces _____________ mature ovum/ova?

4; 1 Complete oogenesis is the process of forming a mature ovum from a precursor female germ cell known as oogonium. Unlike spermatogenesis in which one precursor male germ cell normally produces four spermatocytes, only one ovum is produced by this process, with up to three polar bodies also produced.

The protein glucagon contains 29 amino acids in its active linear form. What is the minimum number of bases present in the mature messenger RNA for this protein?

87

What makes a frameshift mutational event more serious than a point mutational event?

A point mutational event can potentially alter amino acid whereas frameshift alters the entire protein. Added or deleted bases messes up the reading frame until end of the gene.

Which of the following would NOT be an example of an epigenetic influence on a health endpoint?

A single base substitution in the 6th DNA triplet of the beta globin gene leading to the production of "sickle cell" globin, resulting in the expression of sickle cell trait or sickle cell anemia

Which person is an obligate carrier of an autosomal recessive single gene trait or disorder?

A women with free earlobes, whose mother has attached earlobes

What is the most outstanding feature of a mature haploid cell?

Only one chromosome of each pair is present.

Which mature messenger RNA strand correctly reflects the accurate transcription of the following segment of DNA, in which large letters represent introns and small letters represent exons? tTGCGaAccaGaCTtaaAAtTAAA

AUGGUUAUUA

What is the general purpose of tyrosine kinase enzymes?

Activating cyclins by phosphorylation

Which observations in a pedigree indicate a probable autosomal dominant (AD) trait transmission?

Affected males and females appear in every generation

What is the risk for disease expression among the offspring of a woman who has an autosomal recessive disorder when her partner is a carrier for the same disorder?

All children have a 50% risk for being affected and a 50% risk for being a carrier.

Why does an embryo with a balanced translocation have the same chance for normal development that an embryo with a normal karyotype has?

Although the location of the genetic material is abnormal with a balanced translocation, there are no missing or extra alleles.

Couples from which ethnic group would derive the greatest benefit from genetic testing for Tay-Sachs disease?

Ashkenazi Jews

Which type of genetic transmission promotes the continued existence of genetic mutations in single genes?

Autosomal recessive

A patient is identified as an ultra-rapid metabolizer for drugs that are prepared for elimination by CYP2D6. What effect will this have on the patient's ability to benefit from any active drug that is metabolized by this enzyme?

Both intended responses and side effects decrease

Which statement regarding Duchenne muscular dystrophy (DMD) is true?

Because DMD is X-linked recessive, males are affected, and females are carriers.

Which statement regarding classic hemophilia is true?

Because hemophilia is X-linked recessive, males are affected and females are carriers.

Which health screening activity is most important for girls and women with Turner syndrome?

Blood pressure

What activity occurs during M phase of the cell cycle?

Chromosomes separate and two nuclei are created.

Which additional health problem commonly develops in boys with Duchenne muscular dystrophy?

Chronic heart failure

Julia, (aged 32) is BRCA1 positive, which is known to greatly increase the risk for breast and ovarian cancer.She was tested because her mother, who had ovarian cancer, was BRCA1 positive. Julia has decided to have both of her ovaries removed because she believes that, in her family, being BRCA1 positive increases the risk for ovarian cancer only. How should a genetic counselor respond to Julia's statement?

Clarify that a BRCA1 mutation does not preferentially express ovarian cancer over breast cancer in any given family.

Which demographic information could have an important influence on susceptibility to disorders that have a strong genetic component?

Ethnicity

What is the expected outcome when a person (twin A) experiences a large deletion of DNA in one of his noncoding region and his monozygotic twin (twin B) does not?

DNA identification of each twin will be more specific

Which event occurs during mitosis?

Daughter cells are produced that are genetically identical to the parent cell The outcome of mitosis is the formation of two daughter cells that are genetically identical to the parent cell that initiated cell division. Selections A and B are events of meiosis only and do not occur as part of mitosis. Selection D is incorrect in that the 46 separate strands of DNA never assemble into one linear strand

Which statement regarding lysosomal storage diseases is true?

Defective enzymes result in the accumulation of potentially toxic substances

Which term or phrase is used to describe the ability of the environment to cause people to look different and develop different diseases even if they have the same genotype?

Developmental plasticity Developmental plasticity is the ability of the environment to cause different phenotypes to develop from the same genotype. Histone modification is the changes of proteins around the double helix. Phenotype variability is associated with changes in gene sequences compared with "wild-type" genes. Nutrigenomics is the study of the interaction between nutrition and the genome.

A patient tells her nurse that her mother developed dementia at age 42 and that her 48 year-old sister is showing signs cognitive decline. This family history suggests ___________________________. The nurse suggests that this patient meet with a genetic counselor to discuss the pros and cons of testing for mutations, which may be found in the _______________________ genes.

Early-Onset Alzheimer Disease; presenilin 1, presenilin 2, and APP

Which action reflects promotion of genomic care as part of comprehensive health care?

Ensuring that genomic issues potentially influencing a person's health are incorporated into routine care

A 62 year-old patient has consumed ethanol heavily for his entire adult life. Last week, he was diagnosed with squamous cell cancer of the mouth. The nurse is explaining to the patient that environmental factors can affect the expression of genes and increase cancer risk. Which of the following is the mechanism by which alcohol is thought to contribute to the development of head and neck cancers?

Ethanol serves as a methyl donor. When tumor suppressor genes are methylated, cancer can result.

A scientist in a distant country's IVF lab is working to develop a genetic test to screen embryos for mutations in BRCA1 or BRCA2 genes, so that those who have them can be discarded. The goal is to reduce the burden and costs of cancer on society. What area of genetic work or studies does this example represent?

Eugenics Eugenics is the science of improving a human population by controlled breeding to increase the occurrence of desirable heritable characteristics. Eugenics might also involve removal of undesirable traits., such as the mutated BRCA gene, which is linked to cancers of various sorts. Cybernetics is concerned with the merger of persons and machine. Cytogenetics is the study of chromosomes. Genetic imprinting refers to the chemical silencing of gene expression.

Which type of testing is most commonly used to diagnose classic hemophilia?

Factor VIII levels

Which process can cause a person with an XY genotype to have a female phenotype?

Failure of gene expression resulting in a complete absence of androgen receptors

A 19 year-old male has an identical twin brother who was just diagnosed with paranoid schizophrenia. This young man is worried about his personal risk for developing the disorder and is discussing his situation with his health care provider. Which of the following would not be an accurate fact to provide to this patient?

Family members of people with schizophrenia benefit from speaking to genetic counselors, who can help them chose the proper genetic tests for the variant of disease that is most likely to run in their family.

What is the expected expression of a monogenic trait that has its locus on the Y chromosome?

Females never inherit the trait

Which substance fails to form normally in individuals with Marfan syndrome?

Fibrillin

What would be the sequence of DNA that is complementary to a DNA section with the base sequence of CGTCTATGCTAAG?

GCAGATACGATTC

A woman whose family history for breast cancer includes two paternal aunts who developed breast cancer before age 45. Which genetics professional would be most appropriate for assistance in helping this patient understand the health risk posed by this family history?

Genetic counselor

Which of the following is true of the genetics of ADHD (attention-deficit hyperactivity disorder)

Genome wide association studies (GWASs) have found regions on more than 10 chromosomes associated with ADHD

Why is a legend necessary when constructing a pedigree that includes a health history?

Health problems do not have standard symbols.

What is the expected outcome of pregnancy for women with phenylketonuria when the blood levels of phenylalanine are high throughout the pregnancy?

High incidence of cardiovascular birth defects

What is the expected result of a deficiency in the enzyme phenylalanine hydroxylase (PAH)?

High levels of phenylalanine; low levels of tyrosine

Spermatogenesis and oogenesis have some similarities, but also a few key differences. Which of the following is a true statement regarding the two processes?

In spermatogenesis, the prophase of meiosis I takes hours to days, while the prophase of meiosis I lasts years in oogenesis. Crossing over is the lengthening and touching of the chromatids that allows for pieces of sister chromatids to be exchanged. For both spermatogenesis and oogenesis the process occurs during prophase I, although the timing differs between the two processes.

Which factor has the greatest genetic influence in the development of type 1 diabetes mellitus?

Inheritance of particular types of cell surface "immune markers"

What is the most common cause of death among individuals with vascular Ehlers-Danlos (Ehlers-Danlos type IV)?

Intestinal rupture

Which therapeutic option has been found beneficial for patients with type I Gaucher disease?

Intravenous enzyme replacement with imiglucerase (Cerezyme)

Explain why a frameshift mutation occurring at the 15th base in a 639-base-sequence gene is more likely to affect function than a frameshift mutation that occurs at base number 627

It would be more likely to affect function because the frameshift mutation is occurring earlier. Adding or removing around the 15th base would affect hundreds of bases in the sequence, compared to at the 627th base it would only affect a handful.

In what way is hypertrophic tissue growth more advantageous than hyperplastic tissue growth?

Less energy is required for hypertrophic growth More energy is used in the replacement process of tissue growth by hyperplasia than by hypertrophy. Even with hypertrophy, there is a limit to tissue or organ size. Most periods of hypertrophy for normal cells occur during periods of development, such as childhood and adolescence. Although skeletal muscle can hypertrophy with exercise even in older adulthood, it does not proceed at a uniform rate throughout life, nor does the actual differentiated function of the tissue change

Which tissues are most commonly affected by mutation of the CFTR gene?

Lungs and pancreas

At what phase of the cell cycle are chromosomes visible as separate structures?

M

A 25-year-old female who is thin and fit is in for a visit to plan for upcoming laparoscopic surgery for endometriosis. Labs are drawn. Her blood glucose is 210 mg/dL. Further work-up is done including a blood test for islet cell antibodies and one for insulin autoantibodies which return negative. This patient most likely has:

Maturity-onset diabetes of the young (MODY)

Martha has Alzheimer's disease. She and her daughter Melanie provided care for Martha's mother Margaret when she had severe Alzheimer's disease. Now Melanie, age 57, is showing signs of impaired memory. Melanie's daughter Megan is pregnant with her first child and has contacted a genetic counselor to discuss Alzheimer's risk in her family. Who in this family is the proband?

Megan

Which of the following is true about Klinefelter's Syndrome?

Men with Klinefelter Syndrome have difficulty fathering children

What is the best explanation of a child having the physical phenotype of Down syndrome but having a totally normal karyotype on chromosomal analysis of blood?

Mosaicism of trisomy 21 in various tissue

Why does Duchenne muscular dystrophy (DMD) have poor reproductive fitness?

Most affected individuals typically do not have children

Which statement about the X chromosome is true?

Most of the X chromosome genes encode proteins that have no role in female sexual development.

What is the explanation for creatine kinase (CK) levels in a 14-year-old boy with Duchenne muscular dystrophy being much lower now than they were 5 years ago?

Most of the muscle tissue has already been destroyed.

Which activity would a general registered nurse be expected to perform as part of genomic care?

Obtaining an accurate family history and physical assessment data

A patient who has been found to have a mutation in gene allele that greatly increases her risk for a serious health problem has asked a generalist nurse to be present when she discloses this information to her family. What is the nurse's role in this situation?

Patient support

How is sickle cell trait different from sickle cell disease?

People with sickle cell disease are homologous for the mutation, whereas those with sickle cell trait are heterozygous for the mutation.

How do genetic counselors provide genetic/genomic information to patients and families in a nondirectivemanner?

Presenting all facts and available options in a manner that neither promotes nor excludes any legally permitted decision or action

Which cell in the process of oogenesis has the most chromosomes?

Primary oocytes

How are Punnett Squares and pedigrees different?

Punnett Squares represent genotypes and pedigrees represent phenotypes.

Which pair of relatives represents a first-degree relationship?

Sister and brother

A man and his wife are both taking warfarin (Coumadin) daily because of atrial fibrillation. The husband asks why he is prescribed a much smaller than average dose of the drug to keep his international normalized ratio (INR) at 2.0 and his wife takes the average dose even though he is taller and heavier than she is. What is the nurse's best response?

Some people do not break down warfarin as fast as others do, so the drug is more effective at lower dosages

In June of 2013, the U.S. Supreme Court made an important decision regarding property rights in field of genetic research. What did the court decide about patenting of genes?

That isolated pieces of DNA (genes) in their natural form could not be patented

What is the correct interpretation of the statement "the CFTR gene locus is 7q31"?

The CFTR gene alleles are located on the "long arms" of chromosome 7.

Two four year-olds (Charlie and Lisa) have mucopolysaccharidosis I (MPSI). Charlie has severe dysmorphic features and many skeletal anomalies. Lisa has only mildly coarse features and slight developmental delay. What is the best explanation for these differences?

The disorder has wide variability in expression of severity

How is apoptosis related to physiologic homeostasis?

The efficiency of organ/tissue functions is increased. In tissues and organs that are composed of cells capable of undergoing apoptosis (programmed cell death) older or poorly functional cells are removed, making room for new cells generated by mitosis so that the tissue/organ continues to be populated throughout life by optimally functional cells. Apoptosis has no role in preventing or altering germline mutations. Replacing dead or damaged cells with scar tissue reduces organ function and does not contribute to physiologic homeostasis. Cells that undergo apoptosis must respond to the same mitotic restrictions as cells that do not undergo apoptosis.

Why is Down syndrome the most common trisomy disorder seen among live born infants?

The extra alleles from trisomies of larger chromosomes are embryo lethal.

A baby boy is born with six toes (polydactyly) on his right foot, a trait that neither parent has but one that the paternal grandfather has. What is the best explanation for this occurrence?

The father's phenotype results from incomplete penetrance of a dominant allele.

A son with osteogenesis imperfecta is born to parents with no family history of the disease. What is the most likely explanation for the son's disorder?

The gamete of one parent had a spontaneous mutation.

Which factor has the greatest influence on the expression of a genetic disorder such as Prader-Willi syndrome or Angelman syndrome through the process of genomic imprinting?

The gender of the parent transmitting the deletion

A woman who is a carrier for Fabry disease has children with a man who does not have the disorder. Their son has the disease and their daughter also has some symptoms of Fabry disease even though she could only have inherited one affected allele. What is the explanation for the daughter having some symptoms of Fabry disease?

The inactivation of one X chromosome in female cells is a totally random event.

A person's karyotype shows 44 autosomes and one X chromosome. What is the best interpretation of this karyotype?

The karyotype is aneuploid, and the individual has only one allele for each of the genes on the X chromosome.

Why is fertilization of a polar body unlikely to lead to normal embryonic and fetal development?

The lack of cytoplasm would inhibit cellular reproduction.

When calculating the recurrence risk for a complex, possibly polygenic disorder with a couple who already have one child with the disorder, which additional factor has the greatest impact on increasing this risk?

The mother has a brother who also has the same disorder.

Which issue is considered a "red flag" for the need for referral to a genetics professional?

The presence of neurodevelopmental disorders in one or more members of the kindred

How does the proteome differ from the genome?

The proteome changes in response to intracellular and extracellular signals.

Which statement regarding the influence of epigenetic changes on gene expression is always true?

The sequence of base pairs in the gene's DNA and the DNA of its regulatory areas is unchanged

How does an acquired mutation in a somatic cell gene leading to cancer development affect a person's ability to pass on a predisposition for that cancer type to his or her children?

There is no risk of passing on a cancer predisposition to one's children from a somatic cell mutation.

The nurse is caring for a child with acute lymphoblastic leukemia. The child has been genotyped and is homozygous for a TPMT polymorphism, producing very little of the enzyme needed for this drug's metabolism. How would the nurse expect this to affect dosing of the drug 6-mercaptopurine?

This child should receive only a small fraction of the standard dose

A patient participates in a research study sponsored by the teaching hospital where he works. He discovers that he carries two copies of the APOE4 gene, which is associated with late-onset Alzheimer's disease. He shares the information with his colleagues. The following year his surgical privileges are not renewed. He considers the explanations given "dubious" and "inconsistent with recent evaluations." If the decisions made by the hospital were influenced by the results of this patient's genetic testing, the hospital has violated:

Title II of GINA (Genetic Information and Nondiscrimination Act)

Why do genetic counseling programs include extensive courses on laboratory methods in genetics?

To help patients understand testing procedures and results

What is the primary purpose of a pedigree?

To identify family members' places within a kindred and describe their medical history

Which lethal cardiac arrhythmia can occur as a complication of long QT syndrome?

Torsade de pointes

What is the most obvious expected finding when analyzing a four-generation pedigree for sex-linked dominant transmission of a trait?

Transmission is never father to son.

Which syndrome or condition represents monosomy?

Turner syndrome

Which situation is an example of a modifier gene action?

Two children in the same family both have sickle cell disease, but one child has more severe symptoms than the other.

Which type of diabetes has a slow onset and is often diagnosed in North American only when a complication is present?

Type 2 diabetes mellitus

Under which condition(s) would genetic testing for predisposition to an inherited disorder in a minor child be considered reasonable?

When the risk is high and prophylaxis to reduce disorder severity is available

All of the following are true of GINA (the Genetic Information and Nondiscrimination Act) except which of the following?

With GINA signed into law, one can assure patients that they will face no discrimination based on their genetic test results from either insurance companies or employers

Marjorie tells a nurse that she has three aunts with cancer. The two on her father's side were diagnosed with breast and ovarian cancers at ages 42 and 36. She also has one aunt on her mother's side who was diagnosed with breast cancer at age 70. Marjory asks if she should have genetic testing. What should the nurse tell her?

Your family history may indicate an increased risk for breast cancer, and a genetic counselor could help determine whether you could benefit from genetic testing."

Zoe, a 20-year-old woman, shows signs of mild muscle weakness. She has two first cousins on her mother's side who died of Duchenne's muscular dystrophy (DMD). Which explanation regarding Zoe's situation is most likely?

Zoe is a heterozygote showing partial expression.

What is the term used to define alternative forms of a gene that may result in different expression of the trait coded for by that gene?

alleles

When is Meiosis II completed in oocytes?

at fertilization

If the physician in question #1 informed the patient's sons about their genetic risk, this doctor could invoke the ethical principle of _________________ in defending his decision to disclose medical information about their father to the sons, but this principle would be in conflict with the father's ________________.

beneficence; right to privacy

In the United States researchers are experimenting with gene therapy to accomplish which of the following?

fix of deleterious genetic mutations that cause diseases like cystic fibrosis and muscular dystrophy

The process of drug response most subject to genetic variation is _______________, and this process occurs primarily in the

drug activation and deactivation;liver

A patient has begun taking imipramine for depression. Thsi patient has a variant gene that codes for CYP2D6, which makes him an a poor metabolizer. Which of the following signs or symptoms might this patient be exhibiting or experiencing a few days after initiation of therapy?

dry mouth, sedation, and tremor

Which type of testing is most commonly used to diagnose sickle cell disease?

emoglobin electrophoresis

______________________ is the health problem that is the most frequent cause of sudden cardiac death in young athletes, and in families in which this genetic disorder is inherited, it is transmitted as a ________________________ trait.

hypertrophic cardiomyopathy; autosomal dominant

Recommendations from professional organizations about disclosure of genetic information vary around the globe. A nurse in the United Kingdom (England) is working with a physician who has a patient with a heritable form of colon cancer, a disease for which there is effective, early screening. The patient is 48 years old and is undergoing chemotherapy. He has a grim prognosis. He has consistently refused to inform his sons, ages 20 and 18, about the heritability of his particular kind of cancer, even after having been informed by the doctor and nurse that his sons are at risk. To follow the recommendations of his professional organization this physician should:

inform the patient's sons that they are at risk for colon cancer and that screening is available

A patient has a very high concentration of insulin receptors on cells that require insulin for glucose to enter. How should insulin dosages be adjusted to prevent a serious adverse reaction from insulin?

insulin dosages should be decreased bc drug will exert its actions at lower concentrations

What is the term used to describe the organized picture of the paired chromosomes within a cell used to determine whether chromosome numbers, structures, and banding patterns are normal?

karyotype

variants in genes like PPAR-γ, ABCC8, and KCNJ11 are associated with type 2 DM and are being actively studied. Genetic testing for mutations in these genes has not yet been shown to clinically useful, but the hope is that someday, perhaps with refinement of testing, it might be. In addition to helping predict who could be at higher risk for the disease, there is reason to believe that mutational status might help predict:

likelihood of response to different antidiabetic drugs

In the case of Safer v. Estate of Pack, a woman successfully sued the estate of her father's physician. This patient claimed that her diagnosis of ________________________ could have been prevented by early, careful screening, and that the physician did not fulfill his _______________ her of her genetic risk.

metastatic colorectal cancer; duty to warn

Most human genes are located in a cell's ______________, but a few are found in the __________________

nucleus; mitochondria

Preimplantation genetic diagnosis (PGD) involves:

removal of one or two cells from very early embryos and testing those cells for harmful genetic mutations

What does a double horizontal line between a circle symbol and a square symbol as opposed to only line directly connecting two individuals signify on a pedigree?

the individuals are related by blood

For individuals who have increased genetic susceptibility for type 1 diabetes, what is the most common environmental trigger for disease expression?

viral infection