Genetic Testing Mastick Flashcards
What was the first human gene cloned?
insulin
genetechs first product?
human growth hormone
First genetically engineered drug approved by FDA?
Humulin
A (blank) is the analysis of human DNA, RNA, chromosomes, proteins or metabolites in order to detect alterations related to a heritable disorder.
genetic test
What are three biochemical genetic methodologies used for neonatal screening?
analyte, enzyme assays, protein analysis
What are 2 cytogenetic tests?
Karyotyping (Geimsa staining), FISH
Every baby gets what?
a new born screening
What do the new born screening tests screen for?
CF,endocrine, hemoglobin cond., metabolic conditions, anolytes
Why are 2 screening test done on babies?
because they want to have every baby testing but you get better results a week after birth so they do 2 just in case some babies parents dont bring the back
what does mass spectrometry do?
looks at thousand of analytes in blood
What type of methods are direct DNA testing and Deletion/Duplication Analysis?
DNA-Based
What is the website that geneticists go to?
What is the first line of genetic testing?
gene tests
family history and pedigree
What does the gene test website have?
gene reviews, lab directory, clinic directory, illustrated glossary
What is the process by which the nucleotide sequence is determined for a segment of DNA
Sequence Analysis
An entire gene may be sequenced or, more commonly, (blank) of the gene most likely to contain mutations (exons and intron-exon boundaries) are sequenced.
only select regions
The way sequencing is done, you must first make a (blank)
template
To make a template in sequencing what do you use?
Why?
PCR
To amplify the exons and intron-exon boundaries
What is the difficulty with DNA sequencing?
finding which ones are the disease causing mutations
Sequencing a segment of DNA identifies most (blank) from the wild-type.
variations
Testing for the presence of a specific mutation, a specific type of mutation, or set of mutations is called what?
targeted mutation analysis
What gives detection of variation at the DNA level. (sequencing, Southern blotting, PCR)
DNA testing
What detects changes in transcription of specific genes (promotor mutations). Northern blotting, RT-PCR
RNA detection
What do you use to find hemoglobinapathies; changes in protein structure (charge or size).
Protein electrophoresis
What uses antibodies to detect changes in protein abundance via ELISA, western blotting, immuno-histochemistry.
protein detection
What do you use to find inborn errors of metabolism (neonatal screening). Measure analytes, enzyme assays
Biochemical assays
What do you use to detect changes in chromosomes (# or structure). Spectral karyotyping, FISH, G-band karyotyping
cytogenetics
Approx. (blank) DMD patients have a deletion of one or more exons.
2/3
what reveals allelic varients and cannot detect large deletions? Why?
sequence analysis
What compares fragments of DNA to mutated DNA to find mutated genes and reduces the amount of DNA that needs to be sequences to find the mutation?
Mutation scanning
What detects deletions/duplications of an entire exon,multiple exon, or the whole gene.
Deletion/duplication analysis (copy number analysis)
What are used to detect deletions/duplication analysis?
quanititative/real-time PCR, MLPA, SNP microarray
What is the use of PCR to determine the amount of DNA or RNA in a sample,commonly used to detect heterozygous deletion mutations and duplication mutations.
quantitative PCR
testing for hemizygous deletion mutations can be done by what?
standard PCR
What type of PCR must be used to detect heterozygous deletion mutations
quantitative PCR
What testing is used to confirm/rule out a genetic disorder in symptomatic individual?
diagnostic testing
What test is offered to asymptomatic individuals with a family history of genetic disorder?
predictive testing
What test is performed to identify individuals who carry a mutation for an autosomal or x-linked disorder?
Carrier testing
What test is performed during pregnancy to assess the health status of a fetus?
prenatal testing
What test is performed on early embryos resulting from in vitro fertilization?
preimplantation testing
What test is used to help identify individuals with genetic diseases to start treatment as soon as possible?
newborn screening
Wat detects RNA; size of intact mRNA molecule (intact) and abundance. Gene expression levels- promotor mutations.
Northern Blot
can only distinguish large differences, i.e. more than 100 bp
What detects genomic DNA; usesrestriction enzyme digestion;is then transferred to nitrocellulose (blotting); bound with a specific probe for DNA of interest and then
Indicates size or presence of DNA fragments containing gene of interest?
Southern Blot
Can only distinguish large differences i.e. more than 100 bp
PCR can distinguish what?
very small differences in size
VNTR ploymorphisms with PCR is good for what?
Forensics!
What causes muscular dystrophy?
defects in DMD
what does becker muscular dystrophy exhibit?
allelic heterogeneity
Approx. (blank) DMD patients have a deletion of one or more exons?
2/3
Can PCR be used to detect female carriers?
no
What detects point mutations?
sequence analysis
What can be used for to detect deletions associated with carrier status if prior identification of mutation in the family?
quantitative PCR, or FISH
Will females be mosaic for dystrophin expression in skeletal muscle?
NO, because cells are multinucleated and will not show up when searching for protein detection
What are qualitative (SCA) and quantitative disorders of hemoglobin (all forms abab) called as a group?
hemoglobinopathies
What are globin chain imbalances called?
Thalassemias
What chain does SCA effect? WHat codon is effected? what amino acid is changed into what?
Beta chain, 6, glutamate to valine
Every person with sickle cell disease has the same (blank)
point mutation
How can you detect SCA or Sickle-C?
protein electrophoresis (often done as a neonatal screening)
Normal hemoglibin on a protein electrophoresis will migrate how?
it will migrate closest to the positive do to the conserved glutamate. Abnormal wont be as high.
What does direct DNA testing for SCA utilize to detect single base pair differences?
Allele Specific Oligonucleotides (ASO)
If you run a ASO detection of SCA will it detect sickle-C?
No, it wil show up at SCA but wont differentiate between SCA and Sickle-c
Are african american more likely to be carriers of alpha or beta thalassemias?
Alpha
(blank) has no alpha, inclusion bodies of b4 form (HbH).
alpha thalassemias
(blank) has no beta, precipitate of a4 forms
B thalassemias
normal individuals have how many copies of alpha hemoglobin? How many copies of fetal? how may copies of Beta
4
2
2
45% of all a thalassemias have what and are what?
are silent carriers have have one missing alpha chain
20% of alpha thalassemia is missing what?
2 alpha chain genes on same chromosome and show trait
5% of alpha thalassemia are homozygous how?
Both chromosomes are missing one alpha chain gene ( 2 alpha chain genes are missing)
gradation and severity of alpha-thalassemia depends on what?
genotype
20% of what ethnicity carry the –/aa allele and have alpha thalassemia trait (large deletion that covers both alpha genes)
southest asians
45% of what ethnicity carry the allele a-/aa are considered silent carries that create one functional alpha
African Americans
5% of who have two a-/a- and have alpha thalassemia triat.
African Americans
What is moderate to marked anemia called and how many copies are lost?
Hemoglobin H disease
3 copies
What is asymptomatic, but can be detected biochemically and results in reduced RBC size? How many copies are lost?
alpha thalassemia trait, and 2 copies are lost
What is a type of alpha thalaessemia that is lethal and how many copies are lost?
a0 thalassemia (Hb Barts, HYDROPS FETALIS) loss of 4 copies
What are the possible phenotypes of the beta globin gene?
Beta thalassemia minor, beta thalassemia trait, or beta thalassemia major
In b-thalassemia minor, how many mutant alleles are there and what is the expression?
1 mutant and appr. 50%
In the b-thalassemia trait, how many mutant alleles are there and what is the expression like?
2 mutant alleles and intermediate expression
In b-thalassemia major, how many mutant alleles are there and what is the expression?
2 mutant alleles and very low or none
What types of genetic testing can be used to detect carriers? For prenatal testing?
SNP micro array. Fish probe if you know what you are looking for, you can do a western blot, gene sequencing, RFLP.
What is the type of hemoglobin that is caused by an allele of Beta hemoglobin having unequal crossover with fetal hemoglobin?
Is it functionally active? How is it expressed?
Hb lepore, yes it is functionally active, but expressed at low levels due to fetal promotor and not expressed at all in adults
Despite marked molecular heterogeneity of beta thalassemia, the prevalent molecular defects are limited in each at risk population, in fact only (blank) mutations account for 75-95% of the disease alleles.
4-10
How should you test for beta thalassemia?
target mutation analysis (pop. appropriate) and then utilize mutation scanning or sequence analysis
In 45% of cases, no mutations are found when all exons and intron exon boundaries are sequenced. There are also no defects in the mRNA (levels or
size) detected, but no protein is found.
What is the mutation?
There is an intronic sequence that is a hotspot for spontaneous mutations which force exons to invert resulting same mRNA length and maintained length but different sequence.
What testing is done when the gene of interest’s location on a chromosome is known. For example Cystic Fibrosis carrier testing.
Direct testing
what uses the use of several DNA sequence polymorphisms (normal variants) that are near or within a gene of interest to track within a family the inheritance of a disease causing mutation in that gene.
linkage analysis
What does biochemicl testing test?
enzymes, proteins, or analytes (neonatal screning)
mutation scanning is also called (blank)
exon scannin
in mutation scanning the exons are subjected to what kind of tests?
physical
What are four methods of mutation scanning?
DGGE, mismatch cleavage, SSCP, CSGE
For diseases with a high proportion of rare alleles (i.e. family specific mutations), (blank) analysis is not the molecular genetics test used.
mutation
what detects promotor defects?
RNA (northern blotting) and protein assays
northern blotting analyzes what?
promoter mutations or transcription changes in specific genes
(blank) can be used as a probe for southern blots
ASO
RFLP is used with what kind of chromosomes
Homologous with differing restricition sites
how is DNA fingerprinting done?
utilizes VNTR,restricton endonucleases and southern blotting
Fragile x is caused by a lot of (blank) and effects the brain
repeats on FMR1
who is fragile x found?
PCR and southern blotting
(blank) disease is an inherited disease that results in the degeneration of nerve cells. This disease has a late onset and therefore is not seen till later on in life. It is an autosomal dominant disease.
hunington disease
what does huninton use to be found
G8 RFLP, PCR, southernblot
How do you detect DMD?
males PCR females qPCR/fish
How can you detect SCA/THalassemias
protein electrophoresis, ASO testing, mutation analysis
