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44 Cards in this Set
- Front
- Back
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How many autosomes are in the human genome?
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22 pairs
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Fragile-X Syndrome has what type of mutation?
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Trinucleotide repeat
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What are mutations?
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- Permanent change in DNA
Affects germ cells => genetic disease Somatic cells=> tumor or developmental abnormality |
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Sickle cell anemia has what type of mutation?
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Point mutation
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Multifactorial disorders have what type of inheritance?
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Polygenic
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Diseases caused by a single gene defect are called?
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Mendelian Disorders
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Reduced/incomplete penetrance
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Person has a mutant gene but doesn't express it phenotypically
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Variable expressivity
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Trait is seen phenotypically in the individual having the mutations but it is expressed differently among individuals
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De novo mutation
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Affected individuals may not have affected parents because their disease arose from a new mutation
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Transmission patterns of single gene disorders
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Autosomal dominant, recessive, or X-linked
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For autosomal dominant disorders, how many of the offspring will have the disease?
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Half
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Largest group of mendelian disorders are what type?
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Autosomal recessive
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Offspring of heterozygotes for a recessive trait will have what percentage chance of being a carrier?
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2 in 4; half
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What is the age of onset and expression patterns of people w/ recessive disorders?
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Early age of onset and typically complete penetrance
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Are X-linked disorders dominant or recessive?
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Can be both but most are recessive
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What is meant by a hemizygous individual?
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Males only have one X-chrome so they will inherit an X-linked disease
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This is an X-linked dominant disease
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Oral-facial-digital syndrome (OFD) type 1
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Diseases caused by mutations in structural proteins
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- Marfan Syndrome
- Ehlers-Danlos syndrome |
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Mutation of FBN1 gene (abnormal fibrillin) leads to this connective tissue disorder
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Marfran syndrome
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Problems w/ collagen synthesis cause this disorder
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Ehlers-danlos syndrome
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Mutation encoding LDL receptor that leads to impaired metabolism of LDL cholesterol
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Familial Hypercholesterolemia
- homozygotes 5x normal levels and will likely die via MI by 15 - Controlled by statin drugs |
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An autosomal recessive disease where pheylalanine hydroxyls is lacking
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Phenylketonuria
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Autosomal recessive disease that frequently involves the CNS and leads to accumulation of large insoluble particles in macrophages
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Lysosomal storage disease
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Examples of lysosomal diseases
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- Tay-Sachs
- Niemann-Pick - Gaucher - Mucopolysaccharidoses |
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Hurler Disease
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- Caused by deficiency of alpha-L-iduronidase
- BM transplant or enzymes replacement (Expensive!) - 6-10 yr life expectancy w/o Tx |
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Hunter Syndrome
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- Deficiency of L-iduronate sulfatase
- Milder form of Hurler's disease |
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Frequency for multifactorial inheritance?
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2-7 %
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How many genes are responsible for multifactorial diseases?
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2+
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How many newborns have a chromosomal abnormality?
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1 in 200
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Euploid
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Normal chromosome count
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Polyploid
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Increased chrome number that is a multiple of that normally seen
- spontaneous abortions typically result |
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Aneuploid
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Any number that isn't an exact multiple of the normal #
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Trisomy
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1 extra chrome
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Monosomy
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1 less chrome
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Translocation
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Transfer of a part of one chrome to another non homologous chrome
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Most common chrome disorder due to meiotic non-disjunction of chrome 21
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Down Syndrome
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XXY
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Klinefelter Syndrome
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Taurodontism is seen in what sex chrome disorder?
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Klinefelter syndrome
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0X
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Turner Syndrome
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This diagnostic tool uses a probe that recognize sequences specific the chromosomal regions
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FISH
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Uses different colored dyes attached to large segments of the test DNA and normal DNA, followed by hybridization
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Comparative genomic hybridization
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This amplifies the DNA and compares nucleotides of DNA to normal DNA
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PCR analysis
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Prenatal indications for genetic analysis
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- > 34 yrs of age
- Parent that is a carrier of chrome translocation - Hx of previous kids w/ chrome abnormalities - Carrier parent of X-linked disorder |
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Postnatal indications for genetic analysis
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- Multiple congenital abnormalities
- Retardation or developmental delay - Aneuploidy - Sex chrome abnormality - Infertility - Multiple spontaneous abortions |
