Deck 2: Diagnostic Techniques in Medical Genetics

Question 1

You create a pedigree for a client who reports several family members experiencing the same genetic disease. Which aspect of the pedigree indicates that the disorder has complete penetrance?

A) Two cousins have the same disorder.
B) Males and females are affected equally.
C) The disorder does not appear in one family.
D) The disorder appears in the female parents and male children.

Answer 1

B
Explanation: Penetrance is the proportion of organisms having a particular genotype that
actually expresses the corresponding phenotype. If the phenotype is always expressed,
penetrance is complete; otherwise, it is incomplete. One characteristic of complete penetrance is both males and females being equally affected by the disorder. Cousins having the same disorder or the disorder missing an entire family does not demonstrate complete penetrance. A disorder appearing in females and male children a characteristic of an x-linked genetic disorder.

Question 2

A young adult client reports having several genetic disorders in the immediate family and wants to know the chances of having a child with a disorder. Which specimen should you consider collecting in anticipation of having a chromosomal analysis completed for this client?

A) Stool
B) Urine
C) Blood
D) Saliva

Answer 2

C
Explanation: Chromosomal analysis is done by growing human cells in tissue culture, chemically inhibiting mitosis, and staining, observing, photographing, sorting, and
counting the chromosomes. Samples can be obtained from peripheral blood, amniotic fluid, trophoblastic cells from the chorionic villus, bone marrow, and cultured fibroblasts, usually obtained from a skin biopsy. Stool, urine, or saliva samples are not used to complete a chromosomal analysis.

Question 3

A chromosomal analysis is being completed for a client with a questionable genetic disorder. Which technique is used to identify chromosomal abnormalities?

A) Treat with Giemsa stain
B) Grow the cells in a tissue culture
C) Use light microscopy to study the sample
D) Identify the order of the chromosome pairs

Answer 3

A
Explanation: Treating chromosomes with Giemsa stain causes the chromosomes to exhibit transverse bands or G-bands that are specific for each pair of homologs. These G-bands allow smaller segments of each chromosome arm to be identified in order to identify chromosomal abnormalities. Growing the cells in a tissue culture and using light microscopy to study the sample is the process used in chromosomal analysis, in which the chromosomes are routinely rearranged systematically in pairs from longest to shortest and numbered from 1 through 22 to represent the autosomes.

Question 4

A blood sample from a client having genetic testing is being tested through fluorescence in situ hybridization (FISH). What will this type of testing reveal about the client?

A) Detect risk for fertility issues
B) Validate the chromosomal pairs
C) Identify individual gene mutations
D) Predict if offspring will develop an abnormality

Question 5

A client is having genetic testing through fluorescence in situ hybridization (FISH). What is the purpose of the probe with this genetic test?

A) Search for repeating DNA cycles
B) Identify the longest chromosomes
C) Validate the shortest chromosomes
D) Search for genes with the same sequence

Question 6

You review data collected from a client during a health history. For which reason should cytogenetic testing be considered for this client?

A) Experiences seasonal eczema
B) Older sibling spouse has twins
C) Parents alive and both in their 70s
D) Infertility with no physiologic cause

Question 7

A client having genetic testing is asked to provide a strand of hair. How will this sample be used for DNA analysis?

A) Treat with Giemsa stain
B) Create nucleic acid chains
C) Analyze under a microscope
D) Create a polymerase chain reaction

Question 8

A client is scheduled for biochemical analysis to identify a genetic disorder. Which is the focus of this analysis?

A) Genus of intestinal bacteria
B) Amount of subcutaneous tissue
C) Presence or absence of proteins
D) Levels of hormones required for development

Question 9

A 3-month old baby is diagnosed with cystic fibrosis. On which body systems should you prepare teaching for the parents about this disorder?

A) Respiratory and digestion
B) Musculoskeletal and renal
C) Cardiovascular and lymphatics
D) Neurologic and electrolyte balance

Question 10

A client agrees to have genetic testing for a potential disorder. Which statement should you make so that the client understands the potential issues of having this kind of testing?

A) "All of the test findings are confidential."
B) "Genetic testing costs the same as other diagnostic testing."
C) "Most genetic anomalies can be altered by lifestyle changes."
D) "You will not be denied health insurance, but your premiums may increase."