Term
What type of mutation creates a new amino acid in place of a previous one? |
|
Definition
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|
Term
What type of mutation changes the codon to a stop codon? |
|
Definition
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|
Term
What gene is responsible for X inactivation? |
|
Definition
|
|
Term
|
Definition
the individual first effected by the disease |
|
|
Term
What is allelic heterogeneity? |
|
Definition
different mutations in the same locus that cause a variety of expression severity between families not within the same family |
|
|
Term
What is the main difference between genetic drift and natural selection? |
|
Definition
genetic drift is random whereas natural selection is not |
|
|
Term
|
Definition
the movement of genes between popluations making the two populations more similar |
|
|
Term
What does G-banding allow one to do? |
|
Definition
visualize the chromosomes |
|
|
Term
What are the steps in G-banding? (2) |
|
Definition
trypsin digestion
Giemsa staining of bands |
|
|
Term
What chromosome and what mechanism causes the mutation in Cri-du-chat and Williams syndrome?
How would you test for this type of mutation? |
|
Definition
Cri-du-chat is ch. 5
Williams is ch. 7
BOTH ARE MICRODELETIONS
TEST w/ FISH |
|
|
Term
What are the acrocentric chromosomes (5)?
What type of translocation can occur with them? |
|
Definition
13, 14, 15, 21, 22
robertsonian translocation |
|
|
Term
Explain the mechanism of robertsonian translocation? |
|
Definition
two acrocentric chromosomes lose their short arms and subsequently the long arms join together. |
|
|
Term
What are the tips of the chromosomes called? |
|
Definition
|
|
Term
What is the mechanism behind Li-fraumeni syndrome? |
|
Definition
mutation in the TP53 gene which codes for p53.
loss of function |
|
|
Term
How many hits does a gain of function mutation need? |
|
Definition
|
|
Term
What is the highest dizygotic concordance obtainable? Why? |
|
Definition
50% b/c this is the most genetic material the two twins can share |
|
|
Term
What are the three possible combinations of amnion and chorion that can occur with monozygotic twins? |
|
Definition
same amnion and chorion
seperate amnion and chorion
same chorion, seperate amnion |
|
|
Term
What is the difference between variable number of tandem repeats and short tandem repeat polymorphisms, with regards to what they detect? |
|
Definition
variable number of tandem repeats detect minisatellite repeats
short tandem repeat finds microsatellites (2-6bp) |
|
|
Term
What percentage cutoff value defines if two genes are linked? |
|
Definition
two genes are linked if they crossover together more than 50% of the time. |
|
|
Term
What is linkage disequilibrium? |
|
Definition
the tendency for alleles at two linked loci to crossover |
|
|
Term
What method does indirect genetic testing use? |
|
Definition
recombination analysis (genetic linkage) |
|
|
Term
At what week is amniocentisis done?
At what week is chorionic villus sampling done? |
|
Definition
16 weeks for amniocentisis
10-12 wks for chorionic villus sampling |
|
|
Term
Why can chorionic villus sampling give false+/false- results? |
|
Definition
|
|
Term
What are the three steps of PCR? |
|
Definition
denature
anneal
elongation |
|
|
Term
What enzyme is used in the elongation period of PCR that creates the elongation? |
|
Definition
heat stable DNA polymerase |
|
|
Term
What does southern blotting detect?
northern blotting?
Western blotting? |
|
Definition
Southern-DNA
Northern-RNA
Western-protein |
|
|
Term
Which blotting procedures use a DNA probe? |
|
Definition
|
|
Term
Which blotting method uses an antibody to detect substrate? |
|
Definition
|
|
Term
What are microarrays used to detect? |
|
Definition
single nucleotide polymorphisms (SNP) |
|
|
Term
What is the difference between cDNA and normal DNA that will eventually code for a protein? |
|
Definition
|
|
Term
Why when cloning are the DNA fragments inserted into a bacterial plasmid that is antibotic resistance? |
|
Definition
so they can be selected for using an antibiotic medium to get rid of any bacteria that doesn't contain the DNA fragment |
|
|
Term
What type of inheritance results in neither of the 2 alleles being dominant? |
|
Definition
|
|
Term
What is the difference between variable expression and incomplete penetrance? |
|
Definition
variable expression: have the genotype with varying phenotype
incomplete penetrance: some with the genotype will not express the phenotype at all |
|
|
Term
What is the formula for determining penetrance? |
|
Definition
# with pheotype/total # with genotype |
|
|
Term
What is pleiotropy? An example of a disease? |
|
Definition
when one mutation has effects in several different organs
EX: Marfan (fibrilin gene in many locations) or PKU |
|
|
Term
|
Definition
methylates (SAM) an allele making it inactive |
|
|
Term
What are two classic examples of imprinting and consequences of not inheriting the non-imprinted allele? |
|
Definition
angleman and prader willi |
|
|
Term
What chromosome is involved in Prader-willi and angleman syndrome? |
|
Definition
|
|
Term
What is the mechanism of prader willi? |
|
Definition
maternal allele on ch. 15 is methylated normally-->inactive
at the same time the paternal allele on ch.15 is deleted
-->no copy of allele on ch.15 |
|
|
Term
What is the mechanism of Angelman syndrome? |
|
Definition
ch. 15 paternal allele is methylated-->inactive
but the active maternal allele is deleted
-->no active ch. 15 allele |
|
|
Term
What type of diseases are affected by anticipation? |
|
Definition
trinucleotide repeat disorders |
|
|
Term
What are the four main trinucleotide repeat disorders? |
|
Definition
Huntington's
Myotonic dytrophy
Fragile X
Fredrich's Ataxia |
|
|
Term
What are the trinucleotide repeats in the following disorders?
Huntingtons
Myotonic Dystrophy
Fragile X
Friedrich's Ataxia |
|
Definition
Huntingtons CAG
Myotonic CTG
Fragile X CGG
Freidrichs GAA |
|
|
Term
What is loss of heterozygosity? |
|
Definition
there is already an inheritied mutation on the locus causing heterozygote for the mutation
the loss of heterozygosity comes with a second hit resulting in full mutation |
|
|
Term
Define locus heterogenity? |
|
Definition
mutations at different loci producing same phenotype |
|
|
Term
Name three disease examples of locus heterogenity? |
|
Definition
|
|
Term
|
Definition
a mutation in mitochondrial DNA is only passed from mother to offspring. Not all the mitochondria is mutated.
Heteroplasmy is the varying severity of phenotype depending on how much of the mutated mitochondrial DNA is passed on in relation to normal mitochondrial DNA |
|
|
Term
What are three examples of diseases that show heteroplasmy? |
|
Definition
mitochondrial encephalomyopathy
myoclonic epilepsy
lebex herditary optic neuropathy |
|
|
Term
Why do mitochondrial DNA mutations only come from mother? |
|
Definition
b/c sperm mitochondria are lost when sperm enters the egg |
|
|
Term
What is uniparental disomy? |
|
Definition
when the two chromosomes come from the same parent |
|
|
Term
What is the mechanism of prader willi if the patient has two copies of maternal ch. 15? |
|
Definition
uniparental disomy
patient has both maternal copies which are imprinted and thus inactive |
|
|
Term
What is the difference between transversion and transition? |
|
Definition
Transversion is the substituation of a guanine for a thymine reside or vise versa
Transition is the substitutaion of a purine for another purine or a pyrimadine for another pyrimadine |
|
|
Term
What is the Hardy Weinberg equation? |
|
Definition
|
|
Term
What in the Hardy Weinberg equation represents carrier frequency? |
|
Definition
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|
Term
What disease presents secondary to an imprinting event and microdeletion with hypogonadism and hyperphagia? |
|
Definition
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|
Term
What disease presents secondary to imprinting and microdeletion with inappropriate laughter and seizures? |
|
Definition
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|
Term
What are AR modes of inheritance usually a result of? |
|
Definition
|
|
Term
What are manifesting heterozygotes? |
|
Definition
these are females who inherit an X-linked recessive disorder and subsequently inactivate more of the normal X causing mild phenotype |
|
|
Term
How can heterozygotic females for an x-linked recessive disease manifest a pheotype? |
|
Definition
manifesting heterozygotes: x inactivation of a greater proportion of normal X chromosomes |
|
|
Term
In an x-linked dominant disorder, what percentage of daughters of affected fathers have the disorder? |
|
Definition
|
|
Term
What disease causes degeneration of retinal ganglion cells and axons-->central vision loss?
What type of inheritance does it follow? |
|
Definition
Leber's hereditary optic neuropathy
mitochondrial inheritance |
|
|
Term
What protein is defective in achondroplasia? |
|
Definition
|
|
Term
What disorder of short stature is associated with advanced paternal age? |
|
Definition
|
|
Term
In AD-polycystic kidney disease what is true about the kidney (s) effected? |
|
Definition
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|
Term
What chromosome when mutated produces ADPKD? |
|
Definition
|
|
Term
What three other disease is associated with ADPKD? |
|
Definition
polycystic liver
mitral valve prolapse
berry aneurysm |
|
|
Term
What AD disease has associated risk of berry aneurysm? |
|
Definition
|
|
Term
What chromosome is mutated in familial adenomatous polyposis? |
|
Definition
|
|
Term
What gene is deleted in familial adenomatous polyposis? |
|
Definition
|
|
Term
In familial hypercholesterolemia what is the genetic defect? |
|
Definition
abnormal or absent LDL receptor |
|
|
Term
How will heterozygotes for familial hypercholesterolemia present? |
|
Definition
|
|
Term
How will homozygotes for familial hypercholesterolemia present? |
|
Definition
cholesterol very high with tendon xanthomas and MIs |
|
|
Term
What disease presents with recurrent epitaxis, telangiectasia, skin discoloration, and AVMs? |
|
Definition
Hereditary hemorrhagic telangiectasia (Osler Weber) |
|
|
Term
What is the genetic defect in hereditary spherocytosis? |
|
Definition
|
|
Term
What is the cure for hereditary spherocytosis? |
|
Definition
|
|
Term
What chromosome is the Huntington trinucleotide repeat found on? |
|
Definition
|
|
Term
What mutation is often found in MEN2A and MEN2B? |
|
Definition
|
|
Term
What chromosome is mutated in NF1 and NF2 respectively? |
|
Definition
|
|
Term
Which type of neurofibromatosis is associated with phenochromocytomas? |
|
Definition
|
|
Term
What chromosome is associated with the mutation for VHL syndrome? |
|
Definition
|
|
Term
What gene is deleted in von-hippel-lindau disease and what type of gene is it? |
|
Definition
VHL tumor suprressor gene |
|
|
Term
What gene is constituatively active due to mutation in VHL syndrome? What is the result? |
|
Definition
HIF transcription factor-->angiogenic growth |
|
|
Term
What two disorders are very common in Ashkenazic Jews? |
|
Definition
Tay Sachs
Gaucher's type I |
|
|
Term
What disease presents in a child with red, scaled skin after exposure to sun due to lack of a DNA excision repair gene? |
|
Definition
|
|
Term
What is in common between PKU, sickle cell anemia, thalassemia, and hemochromotosis? |
|
Definition
they are all AR inheritance |
|
|
Term
How is xeroderma pigmentosum inheritated? |
|
Definition
|
|
Term
Name 10 common x-linked recessive disorders? |
|
Definition
bruton agammaglobulinemia
Wiskott Aldrich
fabry
G6PD deficiency
ocular albinism
lesch-Nyhan
Duchene/Beckers MD
Hunter's
Hemophilia A/B |
|
|
Term
What chromosome is involved in the Cystic fibrosis mutation? |
|
Definition
|
|
Term
What is the result of a deleted Phe amino acid at position 508 of ch. 7? |
|
Definition
post translational abnormal protein folding-->cystic fibrosis
channel is degraded before reaching the membrane |
|
|
Term
What two infections are common in cystic fibrosis patients? |
|
Definition
psuedomonas and staph aureus |
|
|
Term
How can you treat Cystic fibrosis medically to loosen mucous? |
|
Definition
|
|
Term
What is the most common lethal genetic disease of caucasians? |
|
Definition
|
|
Term
What disease presents often with bilateral vas deferens agensis? |
|
Definition
|
|
Term
What is the MOA of N-acetylcysteine in treating cystic fibrosis? |
|
Definition
cleaves disulfide bonds within mucous glycoproteins |
|
|
Term
What is the genetic mutation mechanism in duchenne's muscular dystrophy? |
|
Definition
frame shift mutation-->no dystrophin gene |
|
|
Term
What is the longest known human gene? |
|
Definition
|
|
Term
|
Definition
|
|
Term
What lab value and pathology specimen is needed to dx muscular dystrophy? |
|
Definition
elevated CPK
muscle biopsy |
|
|
Term
What X linked dominent disorder involves DNA chromosomal breakage? |
|
Definition
|
|
Term
Name three clinical manifestations of fragile X? |
|
Definition
large testes
large jaw
large ears |
|
|
Term
What are the first and second most common causes of genetic mental retardation? |
|
Definition
|
|
Term
What heart condition is assoicated with Fragile X syndrome? |
|
Definition
|
|
Term
What disorder can be diagnosised by putting DNA in a folate deficient bath or methotrexate followed by southern blot? |
|
Definition
|
|
Term
What are the three surviable trisomies with names and chromosome? |
|
Definition
Down 21
Edwards' 18
Patau's 13 |
|
|
Term
What is the most common trisomy that results in miscarriage? |
|
Definition
|
|
Term
In addition to the three most common surviable trisomies what other trisomy disorder can survive b/c of increase in mosaicism? |
|
Definition
|
|
Term
What is the result of AFP, hCG, inhibin, and estriol screening during pregnancy in a patient with Downs? |
|
Definition
AFP and estriol decreased
hCG and inhibin increased
|
|
|
Term
What will the ultrasound show in a Down's pregnancy? |
|
Definition
|
|
Term
What trisomy presents can present with duodonal atresia? |
|
Definition
|
|
Term
What three diseases/disorders are down's patients at risk for? |
|
Definition
Drinking age is 21--> may need AAA
Acute lymphoblastic leukemia
Atrial Septal Defect (and VSD)
Alzheimers at early age
|
|
|
Term
What are the three possible genetic ways an individual can acquire down's syndrome? |
|
Definition
nondisjuction (95%)
robertsonian translocation (14 and 21) 4%
mosacism (1%) |
|
|
Term
What is the mechanism of mosaicism causing Downs? |
|
Definition
nondisjuction during an early mitosis |
|
|
Term
What are the three main clinical findings in a patient with edwards syndrome? |
|
Definition
election age is 18--> president J.F.K.
small jaw
overlapping fingers
clenched fingers (knuckles) |
|
|
Term
What are the three main clinical presentations of Patau's syndrome? |
|
Definition
puberty age is 13-->all have "P"
holoproencephaly
polydactyly
cleft palate
|
|
|
Term
What is the difference between pericentric and paracentric inversions? Which can go through miosis? |
|
Definition
pericentric includes the centromere and can go through miosis
paracentric doesn't include centromere and cannot go through meiosis |
|
|
Term
What is the characteritis finding in Cri-du chat syndrome? |
|
Definition
|
|
Term
What disease presents with hypercalcemia due to senstivity to vit D, well developed verbal skills, and very friendly personality? |
|
Definition
|
|
Term
What type of facie does a William's syndrome patient have? |
|
Definition
|
|
Term
What are the five clinical manifestations of the 22.q.11 deletion disorders? |
|
Definition
CATCH 22
Cleft palate
abnormal facies
Thymic aplasia
carciac anomolies
hypocalcemia |
|
|
Term
What is the main difference between DiGeorge Syndrome and Velocardiofacial syndrome? |
|
Definition
DiGeorge invovles thymus and parathyroid problems
Velocardiofacial involves facial problems (palate) |
|
|
Term
What is the translocation in CML and what results? |
|
Definition
CML: (9:22)-->philadelphia chromosome-->platelet derived growth factor defect |
|
|
Term
What is the translocation involved in AML? |
|
Definition
|
|
Term
What translocation is involved in follicular lymphoma? |
|
Definition
|
|
Term
What translocation is involved in Burkitts lymphoma? |
|
Definition
|
|
Term
What translocation is involved in mantle cell lymphoma? |
|
Definition
|
|
Term
What is the result of 15:17 translocation? |
|
Definition
|
|