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Cytogenetics Review Questions (view source)
Revision as of 15:55, 5 August 2015
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== | ==Lecture 1== | ||
{{hidden| List the three broad categories of clinical indications for chromosomal analysis.|Prenatal, Constitutional, Cancer/Acquired}} | {{hidden| List the three broad categories of clinical indications for chromosomal analysis.|Prenatal, Constitutional, Cancer/Acquired}} | ||
{{hidden|Which family members should have chromosomal analysis?| | {{hidden|Which family members should have chromosomal analysis?| | ||
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{{hidden|What is SCE (Sister chromatid exchange?|SCE (sister chromatid exchange) is the interchange of homologous segments between two chromatids of one chromosome, grow the cells under special conditions to produce a differential staining of sister chromatids.}} | {{hidden|What is SCE (Sister chromatid exchange?|SCE (sister chromatid exchange) is the interchange of homologous segments between two chromatids of one chromosome, grow the cells under special conditions to produce a differential staining of sister chromatids.}} | ||
{{hidden|What is DAPI staining?|DAPI staining produces bright fluorescence of the heterochromatin regions of 1,9,16, and Y, as well as the centromere of 15, and is used to id marker chromosomes or translocations of Y.}} | {{hidden|What is DAPI staining?|DAPI staining produces bright fluorescence of the heterochromatin regions of 1,9,16, and Y, as well as the centromere of 15, and is used to id marker chromosomes or translocations of Y.}} | ||
{{hidden|Explain how chromosomal breakage studies are used to diagnose Fanconi's anemia.| Cultured cells are treated with | {{hidden|Explain how chromosomal breakage studies are used to diagnose Fanconi's anemia.|Cultured cells are treated with Diepoxybutane, or mitomycin C to induce breakage, those cells with chromosomes prone to breakage are especially susceptible and this can be seen as gaps, breaks, deletions, triradial, quadriradial, dicentric, and complex figure in the metaphase.}} | ||
== | ==Lecture 2== | ||
{{hidden|Describe the 4 steps of mitosis.|Prophase, metaphase, anaphase, telophase}} | {{hidden|Describe the 4 steps of mitosis.|Prophase, metaphase, anaphase, telophase}} | ||
{{hidden|List the 8 steps of meiosis.| | {{hidden|List the 8 steps of meiosis.| | ||
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*Meiosis 2( Prophase 2, Metaphase 2, Anaphase 2, Telophase 2).}} | *Meiosis 2( Prophase 2, Metaphase 2, Anaphase 2, Telophase 2).}} | ||
{{hidden|What is the main difference between constitutional and acquired chromosome anomalies.|Constitutional affects the whole patient, acquired usually limited to 1 organ.}} | {{hidden|What is the main difference between constitutional and acquired chromosome anomalies.|Constitutional affects the whole patient, acquired usually limited to 1 organ.}} | ||
{{hidden|What at the three main categories of patient features associated with unbalanced constitutional chromosomal anomalies? | {{hidden|What at the three main categories of patient features associated with unbalanced constitutional chromosomal anomalies?| | ||
*1) dysmophy | *1) dysmophy | ||
*2) Visceral malformations, | *2) Visceral malformations, | ||
*3) developmental/psychomotor delay.}} | *3) developmental/psychomotor delay.}} | ||
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{{hidden|What is the karyotype for a female infant with cri-du-chat?|46,XX,del(5)(p15.1)}} | {{hidden|What is the karyotype for a female infant with cri-du-chat?|46,XX,del(5)(p15.1)}} | ||
== | ==Lecture 3== | ||
{{hidden|What is FISH?|FISH is a molecular cytogenetic technique in which flourescently labelled DNA probes are hybridized to metaphase spreads or interphase nuclei.}} | {{hidden|What is FISH?|FISH is a molecular cytogenetic technique in which flourescently labelled DNA probes are hybridized to metaphase spreads or interphase nuclei.}} | ||
{{hidden|When is interphase FISH more helpful than metaphase?|Interphase FISH is particularly useful in samples where there is poor culture growth such as bone marrow or cancer tissue.}} | {{hidden|When is interphase FISH more helpful than metaphase?|Interphase FISH is particularly useful in samples where there is poor culture growth such as bone marrow or cancer tissue.}} | ||
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{{hidden|How do CGH arrays work?|CGH arrays allow hundreds-thousands of probes to be used to compare the index and the reference genome, giving a complete chromosomal analysis that depends on the resolution of the probe.}} | {{hidden|How do CGH arrays work?|CGH arrays allow hundreds-thousands of probes to be used to compare the index and the reference genome, giving a complete chromosomal analysis that depends on the resolution of the probe.}} | ||
== | ==Lecture 4== | ||
{{hidden|List 3 solid tumours for which cancer cytogenetics are currently used in prognosis and treatment.| | |||
*1. Lymphoma | |||
*2. Breast cancer | |||
*3. Bladder carcinoma}} | |||
{{hidden|What is a chromosomal instability syndrome?|There are several rare single gene syndromes in which there is a characteristic cytogenetic abnormality; affected individuals exhibit elevated rates of chromosome instability, leading to chromosomal rearrangements.}} | |||
{{hidden|What are the features of ataxia telangiectasia?| | |||
*1) AR inhertiance 1/40,000, ATM:11q22.3-q23.1 | |||
*2) Cerebellar ataxia | |||
*3) Telangiectasia | |||
*4) Growth retardation | |||
*5) Immunodeficiency | |||
*6) Radiosensitivity *tx with conventional radiation doses, could be fatal | |||
*7) Cytogenetics: Chromosomal breakages, telomere instability, radiation sensitivity t(7;14)}} | |||
{{hidden|What is Nijmegen Breakage Syndrome?| | |||
*1. microcephaly | |||
*2. Bird like face | |||
*3. Radiosensitivity | |||
*4. rearrangements between 7 and 14, AR, rare NBS1(8q21.3) | |||
*5. sensitive to x-rays and bleomycin | |||
*6. Growth and mental retardation | |||
*7. Ovarian failure | |||
*8. Prone to b-cell lymphomas}} | |||
{{hidden|What is Bloom syndrome?| | |||
*AR inheritance, rare (1/160,000, BLM:15q26.1, SCE and quadrils | |||
* growth retartdation/ short stature | |||
* sun sensitivity / facial lesions | |||
*Ashkenazi jews}} | |||
{{hidden|What is Xeroderma pigmentosum?|}} | |||
{{hidden|What is Fanconi Anemia?|}} | |||
{{hidden|What is ICF Syndrome?|}} | |||
{{hidden|What is Roberts Syndrome?|}} | |||
{{hidden|What karytype is most at risk of gonadoblastoma?|}} | |||
{{hidden|What cancer are Kleinfelters patients at increased risk of?|}} | |||
{{hidden|What lymphoproliferative disorders are associated with Down's Syndrome?|}} | |||
{{hidden| | |||
== Lecture 5 == | |||
==Miscellaneous== | ==Miscellaneous== | ||
{{hidden|What are the steps in preparing a cytogenetics tissue specimen?| | |||
*1. Specimen received in flow medium and accessioned asap. | |||
*2. Specimen cut-up (+/- treated with collagenase), filtered /18G needle | |||
*3. Seeded into flask | |||
*4. Cultured at 37C 5% CO2 x 48hours | |||
*5. Flask flooded with 2ml of media | |||
*6. Cultured at 37C 5% CO@ x 2-10days | |||
*7. Trypsinize to coverslip when flask growth is confluent | |||
*8. Colcemid added to the coverslip x 30min (1/12 dilution) | |||
*9. Aspirate off colcemid | |||
*10. Add hypo (1/2 0.54 KCl, 1/2 0.75 NaCitrate) x 30 min | |||
*11. Add 2mL of fix (1/3 Methanol, 1/3 }} | |||
{{hidden|What is Allerdice or Sandy Point Syndrome?|It is a chromosomal disorder discovered in Sandy Point, NL by Dr. Penny Allderdice, inv(3)(p25q21) characterized by affected offspring with multiple congenital anomalies with surviving children exhibiting severe growth and developmental delays.}} | {{hidden|What is Allerdice or Sandy Point Syndrome?|It is a chromosomal disorder discovered in Sandy Point, NL by Dr. Penny Allderdice, inv(3)(p25q21) characterized by affected offspring with multiple congenital anomalies with surviving children exhibiting severe growth and developmental delays.}} | ||
{{hidden|What is the most common robertsonian translocation?|Translocation between the long arms of 13 and 14.}} | {{hidden|What is the most common robertsonian translocation?|Translocation between the long arms of 13 and 14.}} | ||
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{{hidden|What is the most common cause of triploidy?|Dispermy in 60%}} | {{hidden|What is the most common cause of triploidy?|Dispermy in 60%}} | ||
{{hidden|What is the recurrence risk for parents of Down's syndrome child with a "free chromosome"?|1%}} | {{hidden|What is the recurrence risk for parents of Down's syndrome child with a "free chromosome"?|1%}} | ||
{{hidden|List 5 features of Trisomy 8.| | |||
*1. Prominent cup-shaped ears | |||
*2. Prominent lips | |||
*3. Somewhat prominent forehead | |||
*4. IQ usually 45 to 75 but some have near normal intelligence | |||
*5. Deep, longitudinal grooves on soles of feet | |||
*6. Joint abnormalities | |||
*7. Usually mosaic }} | |||
{{hidden|List 5 features of Trisomy 9.| | |||
*1. Growth deficiency (prenatal) | |||
*2. Deep-set eyes | |||
*3. Low-set, misshapen ears | |||
*4. Small lower jaw causes upper lip to overlap lower lip | |||
*5. Joint abnormalities | |||
*6. Heart and kidney abnormalities | |||
*7. Small genitalia (males) | |||
*8. Most have severe mental retardation | |||
*9. Usually mosaic}} | |||
{{hidden|List 5 features of Trisomy 13.| | |||
*1. Cleft lip and/or palate | |||
*2. Low set, misshapen ears | |||
*3. Small eyes | |||
*4. Hemangioma(s) on the face/forehead | |||
*5. Defective lateral differentiation of the brain (some have holoprosencephaly) | |||
*6. Sixth finger on ulnar side of hand | |||
*7. Heart and kidney abnormalities | |||
*8. Cryptorchidism in male; bicornate uterus in females | |||
*9. Severe mental retardation}} | |||
{{hidden|List 5 features of Trisomy 14.| | |||
*1. Normal weight but short length at birth | |||
*2. Narrow deep-set eyes | |||
*3. Short, bulbous nose | |||
*4. Small lower jaw | |||
*5. Low-set, misshapen ears | |||
*6. Heart abnormalities | |||
*7. Severe mental retardation | |||
*8. Usually mosaic }} | |||
{{hidden|List 5 features of Trisomy 18.| | |||
*1. Growth deficiency (prenatal) | |||
*2. Prominent occiput | |||
*3. Small mouth and jaw | |||
*4. Low-set, misshapen ears | |||
*5. Short sternum | |||
*6. Clenched hand | |||
*7. Short big toe, often flexed upward | |||
*8. Rocker-bottom" feet | |||
*9. Small pelvis with limited hip movement | |||
*10. Heart abnormalities | |||
*11. Severe mental retardation}} | |||
{{hidden|List 5 features of Trisomy 21.| | |||
*1. Flat face | |||
*2. Brushfield spots present when eyes are blue | |||
*3. Upslanting eyes | |||
*4. Small ears | |||
*5. Small mouth (with tongue often protruding) | |||
*6. short fingers (especially fifth | |||
*7. Heart abnormalities in some cases | |||
*8. IQ usually 25-50 but occasionally higher}} | |||
{{hidden|What is the most common outcome of a pregnancy when the parent has a balanced translocation?|Misscarriage}} | |||
==Peripheral Blood Culture and Harvest== | ==Peripheral Blood Culture and Harvest== | ||