Question 1

Which patients would be candidates for genetic testing for long QT syndrome (LQTS)?

Accepted Answer

Clinical genetic testing is available for long QT syndrome (LQTS).Genetic testing is very helpful within families of patients with LQTS.If the family member has a prolonged QTc interval,the reasonable assumption during the cardiac and genetic work-up is that the person has the mutation.It is also important to test family members with normal QTc intervals because up to 50% have "concealed" LQTS,meaning they have a positive genotype and negative phenotype (normal QT on the resting ECG).This is because of a genetic concept termed penetrance,in which the same gene does not have the same phenotypic effect on everyone who is affected.If a person carries the genetic mutation but has a normal QT interval at rest,he or she may still be vulnerable during exercise or physiologic stress.Frequently patients are identified after a syncopal episode,a life-threatening dysrhythmia such as torsades de pointes,or sudden cardiac death.Hemophilia A and B are associated with bleeding disorders.The FTO gene is associated with obesity.

Question 2

What is a genetic variant that exists in greater than 1% of the population termed?

Accepted Answer

When a genetic variant occurs frequently and is present in 1% or more of the population,it is described as a genetic polymorphism.The term genetic mutation refers to a change in the DNA genetic sequence that can be inherited that occurs in less than 1% of the population.Genetic material in the chromosome can also be deleted and new information from another chromosome can be inserted or can be a tandem repeat (multiple repeats of the same sequence).

Question 3

Hemophilia A is an inherited disease.Which statements would be determined by the family pedigree regarding hemophilia A?

Accepted Answer

In an X-linked disorder,each son has a 50% chance of having the disorder and each daughter has a 50% chance of being a carrier.In a family pedigree,the absence of direct male-to-male transmission makes this condition identifiable as an X-linked disorder.

Question 4

A family pedigree is used to determine whether a disease has a genetic component.What does a proband indicate in a family pedigree?

Accepted Answer

For nurses,it is important to ask questions that elucidate which family members are affected versus those who are unaffected and then to identify the individuals who may carry the gene in question but who do not have symptoms (carriers).The proband is the name given to the first person diagnosed in the family pedigree.Homozygous versus heterozygous determines if the disorder is carried by a gene from one or both parents.The xy band determines if the disorder is carried through the sex genes.A disease locus is the genetic address of the disorder.

Question 5

What is the study of all the genetic material within the cell and its impact on biologic and physical characteristics called?

Accepted Answer

Genomics refers to the study of all of the genetic material within cells and encompasses the environmental interaction and impact on biologic and physical characteristics.Each somatic chromosome,also called an autosome,is made of two strands,called chromatids,which are joined near the center.A karyotype is the arrangement of human chromosomes from largest to smallest.A specialized class of proteins called histones organizes the double-stranded DNA into what looks like a tightly coiled telephone cord.

Question 6

A specialized class of proteins that organizes the double-stranded DNA into what looks like a tightly coiled telephone cord is known which of the following?

Accepted Answer

A specialized class of proteins called histones organizes the double-stranded DNA into what looks like a tightly coiled telephone cord.Genomics refers to the study of all of the genetic material within cells and encompasses the environmental interaction and impact on biologic and physical characteristics.Each somatic chromosome,also called an autosome,is made of two strands,called chromatids,which are joined near the center.A karyotype is the arrangement of human chromosomes from largest to smallest.

Question 7

Which disorders are classified as a single-gene disorder?

Accepted Answer

Cystic fibrosis,sickle cell disease,hemophilia A,and Marfan syndrome are examples of single-gene disorders.Down syndrome is a chromosome disorder (extra chromosome 21),and cardiovascular atherosclerotic disease and type 2 diabetes are examples of complex gene disorders that result from an interaction of genetic and environmental factors.

Question 8

Each chromosome consists of an unbroken strand of DNA inside the nucleus of the cell.What is the arrangement of human chromosomes termed?

Accepted Answer

A karyotype is the arrangement of human chromosomes from largest to smallest.Each somatic chromosome,also called an autosome,is made of two strands,called chromatids,which are joined near the center.Genomics refers to the study of all of the genetic material within cells and encompasses the environmental interaction and impact on biologic and physical characteristics.A specialized class of proteins called histones organizes the double-stranded DNA into what looks like a tightly coiled telephone cord.

Question 9

The patient is placed under general anesthesia for a carotid endarterectomy.During the surgery,the patient develops muscle contracture with skeletal muscle rigidity,acidosis,and elevated temperature.What is a possible cause for malignant hyperthermia?

Accepted Answer

Individuals with polymorphisms in the ryanodine receptor gene (RYR1)at chromosome 19q13.1 are at risk of a rare pharmacogenetic condition known as malignant hyperthermia.In affected individuals,exposure to inhalation anesthetics and depolarizing muscle relaxants during general anesthesia induces life-threatening muscle contracture with skeletal muscle rigidity,acidosis,and elevated temperature.Warfarin is being researched as a variant in the VKOR1 gene and in the cytochrome P450 enzyme CYP2C9 gene.

Question 10

What was the goal of the Human Genome Project?

Accepted Answer

The Human Genome Project was a huge international collaborative project that began in 1990 with the goal of making a map of all the human genes (the genome).The final genome sequence was published in 2003.The HapMap project was to identify haplotype tags.The Genome-Wide Association Studies was used to expose untaggable SNPs and recombination hot spots.The 1000 Genomes project was used to map all the human genes.

Question 11

Which type of genetic disorder occurs when there is an interaction between genetic and environmental factors such as that which occurs with type 2 diabetes?

Accepted Answer

In multifactorial disorders there is an interaction between vulnerable genes and the environment.Cardiovascular atherosclerotic diseases and type 2 diabetes are examples of multifactorial disorders that result from an interaction of genetic and environmental factors.

Question 12

To achieve a consistent distance across the width of the DNA strand,the nucleotide base guanine (G)can only be paired with what other genetic material?

Accepted Answer

Four nucleotide bases-adenine (A),thymine (T),guanine (G),and cytosine (C)-comprise the "letters" in the genetic DNA "alphabet." The bases in the double helix are paired T with A and G with C.The nucleotide bases are designed so that only G can pair with C and only T can pair with A to achieve a consistent distance across the width of the DNA strand.The TA and GC combinations are known as base pairs.

Question 13

What are the studies called that are done on large,extended families who have several family members affected with a rare disease?

Accepted Answer

In genetic epidemiologic research of a rare disease,it can be a challenge to find enough people to study.One method is to work with large,extended families,known as kinships,which have several family members affected with the disease.Genetic association studies are usually conducted in large,unrelated groups based on demonstration of a phenotype (disease trait or symptoms)and associated genotype.Genetic epidemiology represents the fusion of epidemiologic studies and genetic and genomic research methods.Phenotypes are different at different stages of a disease and are influenced by medications,environmental factors,and gene-gene interaction.

Question 14

Philadelphia translocation is a specific chromosomal abnormality that occurs from a reciprocal translocation between chromosomes 9 and 22,where parts of these two chromosomes switch places.This abnormality is associated with which disease?

Accepted Answer

Philadelphia chromosome or Philadelphia translocation is a specific chromosomal abnormality associated with chronic myelogenous leukemia.It occurs from a reciprocal translocation between chromosomes 9 and 22,where parts of these two chromosomes switch places.Hemophilia A is a sex-linked inheritance.Obesity is being studied with the FTO gene on chromosome 16.Marfan syndrome is classified as a single-gene disorder.

Question 15

What is the study of heredity particularly as it relates to the transfer heritable physical characteristics called?

Accepted Answer

Genetics refers to the study of heredity,particularly as it relates to the ability of individual genes to transfer heritable physical characteristics.Each somatic chromosome,also called an autosome,is made of two strands,called chromatids,which are joined near the center.A karyotype is the arrangement of human chromosomes from largest to smallest.A specialized class of proteins called histones organizes the double-stranded DNA into what looks like a tightly coiled telephone cord.

Question 16

Why are monozygotic twins separated at birth used to study the effects of genetics versus environment?

Accepted Answer

Studies of identical twins offer a unique opportunity to investigate the association of genetics,environment,and health.Identical twins are monozygotic and share an identical genome.Monozygotic twins are the same sex.Studies occur much less frequently today because tremendous efforts are made to keep siblings together when they are adopted.Genetics can be stable in a study group,but the environment and health issues are dynamic even in a controlled study group.

Question 17

Prader-Willi syndrome (PWS)is a rare genetic disorder in which genes on chromosome 15 (q11.2-13)are deleted.What type of disorder is PWS?

Accepted Answer

Prader-Willi syndrome (PWS)is a chromosome disorder as a result of several missing genes on chromosome 15.In chromosome disorders,the entire chromosome or very large segments of the chromosome are damaged,missing,duplicated,or otherwise altered.

Question 18

What was the Genetic Information Nondiscrimination Act (GINA)of 2008 designed to prevent from happening?

Accepted Answer

The Genetic Information Nondiscrimination Act (GINA)of 2008 is an essential piece of legislation designed to prevent abuse of genetic information in employment and health insurance decisions in the United States.One of the paramount concerns in the genomic era is to protect the privacy of individuals' unique genetic information.Many countries have established biobanks as repositories of genetic material,and many tissue samples are stored in medical center tissue banks.Some people who may be at risk for a disorder disease will not be tested because they fear that a positive result may affect their employability.GINA also mandates that genetic information about an individual and his or her family has the same protections as health information.

Question 19

What is an example of direct-to-consumer genomic testing?

Accepted Answer

An example of direct-to-consumer testing is paternity testing from buccal swabs of the child and father.Genetic testing can be done through biopsies and amniocentesis,but they are performed in a facility by a medical professional.Drug testing and genomic testing are two different tests and are unrelated.

Question 20

The process that is used to make polypeptide chains that constitute proteins can be written as:

Accepted Answer

The nucleotides A,T,C,and G can be thought of as "letters" of a genetic alphabet that are combined into three-letter "words" that are transcribed (written)by the intermediary of ribonucleic acid (RNA).The RNA translates the three-letter words into the amino acids used to make the polypeptide chains that constitute proteins.This process may be written as DNA → RNA → protein.

Quiz 4: Genetic Issues

Which patients would be candidates for genetic testing for long QT syndrome (LQTS) ?