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Difference between revisions of "Cytogenetics Review Questions"
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{{hidden|What is imprinting?|Normally we inherit one copy of each gene from each parent, some genes are only expressed when they are inherited paternally, some only when maternally, this differential expression based on inheritance is called imprinting, and changes generation to generation.}} | {{hidden|What is imprinting?|Normally we inherit one copy of each gene from each parent, some genes are only expressed when they are inherited paternally, some only when maternally, this differential expression based on inheritance is called imprinting, and changes generation to generation.}} | ||
{{hidden|Which chromosomes are known to have imprinted genes?|Chromosomes 6,7,11,14,and 15.}} | {{hidden|Which chromosomes are known to have imprinted genes?|Chromosomes 6,7,11,14,and 15.}} | ||
{{hidden|Describe Prader-Willi Syndrome.| | {{hidden|Describe Prader-Willi Syndrome.|Features: hypotonia, obesity, developmental delay, hypogonadism, short stature, 70%: del(15q11-13), 25% uniparental disomy, 2%:other, diagnoses by FISH for microdeletion, or DNA methylation; due to absence of paternally derived PWS/AS gene }} | ||
{{hidden|Briefly describe Williams Syndrome.|Deletion of one elastin allele (7q11.23 = 96% of cases), multi-system d/o characterized by: Growth & developmental delay, characteristic facies & personality, supra valvular stenosis, idiopathic infantile hypercalcemia (connective tissue / vascular)}} | {{hidden|Briefly describe Williams Syndrome.|Deletion of one elastin allele (7q11.23 = 96% of cases), multi-system d/o characterized by: Growth & developmental delay, characteristic facies & personality, supra valvular stenosis, idiopathic infantile hypercalcemia (connective tissue / vascular)}} | ||
{{hidden|Describe DeGeorge Syndrome.|95% 22q11.2 deletion, 5% FISH negative; AD inherit; 1) Conotruncal heart defects, 2)uropathy, 3)polyhydramnios,4)increased nuchal translucency, 5) IUGR, 6)thymic hypoplasia, 7) characteristic facies, 8) hypoparathyroidism, 9)MR/DD}} | |||
{{hidden|What is SKY?|A chromosomal analysis technique that has the ability to paint each pair of chromosomes and the sex chromosomes a different flourescing colour.}} | |||
{{hidden|What kinds of chromosomal transformations is SKY used for?|1) translocations, 2) insertions, 3)marker chromosome identification, 4) cancer tumour genetics}} | |||
{{hidden|What are three limitations of SKY?|1) cannot detect del,dup,inv, 2) interpretation difficult if colours too similar}} | |||
{{hidden|Explain the basic principle of Comparative Genomic Hybridization.|References genomes and the index genome are mixed, if the index genome substantially differs from the reference genome then there will be a neg signal loss or gain for that probe's flourescence, this can be used to determine if there is one allele in the index case that is missing or in excess compared to the reference genome.}} | |||
{{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.}} | |||
==Unit 4== | |||
==Miscellaneous== | |||
{{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 non-robertsonian translocation?|t(11;22)(q23;q11)}} | |||
{{hidden|What is a marker chromosome?|A structurally abnormal chromosome in which no part can be identified cytogenetically.}} | |||
{{hidden|What is the most common chromosomal abnormality in humans?|Aneuploidy - about 5% of pregnancies.}} | |||
{{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|List 5 features of Trisomy 8.|}} | |||
{{hidden|List 5 features of Trisomy 9.|}} | |||
{{hidden|List 5 features of Trisomy 13.|}} | |||
{{hidden|List 5 features of Trisomy 14.|}} | |||
{{hidden|List 5 features of Trisomy 18.|}} | |||
{{hidden|List 5 features of Trisomy 21.|}} | |||
{{hidden|What is the most common outcome of a pregnancy when the parent has a balanced translocation?|Misscarriage}} | |||
==Peripheral Blood Culture and Harvest== | |||
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