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22 Cards in this Set
- Front
- Back
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What gave Huntington the ability to view the hereditary nature of the disease named after him?
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He was the third generation of the town's physicians in East Hampton, NY. In a small town, he could witness the disease being passed down to younger generations.
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What are the three fundamental features of the disease described by Huntington?
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chorea - dance-like movements
dementia - usually appears after chorea and marks the accelerated course of the disease hereditability - thread can also be broken; doesn't appear until age 35-50 |
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Who established the science of genetics?
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Gregor Mendel, 1866
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genotype
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genetic constitution of an organism
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phenotype
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observable characteristic or trait of an organism; effect made on the organism by the genes that it carries
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What are three questions Huntington might have been prompted to ask about the disease he observed?
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1. Does the disease occur equally in males and females?
2. Does the disease tend to skip generations? 3. What is the probability of occurrence in the children of an afflicted parent? |
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Why is it rare to find an autosomal dominant pattern in a fatal hereditary disease?
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Most of these diseases would be fatal before the individual has time to reproduce and pass along the gene; therefore the disease would not be passed on to the next generation.
In the case of Huntington's disease, its late appearance allows individuals to pass it on before the disease is observed in the parent. |
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Who discovered the location of the Huntington's Disease gene?
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Nancy Wexler, 1980's, Lake Maracaibo in Venezuela
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What did Nancy Wexler determine about HD?
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gene is located on the short arm of chromosome 4, in a location near a marker that segregates with the gene 97% of the time.
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How can individuals determine whether they have HD?
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100% accurate test due to identification of the HD gene itself in 1993
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Describe the pathology associated with Huntington's Disease.
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massive destruction of the corpus striatum, part of the basal ganglia (extrapyramidal motor system)
also cortical cell loss, but usually not as dramatic |
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What is responsible for the deterioration associated with Huntington's Disease?
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When there is a sequence of CAG repeats, this encodes for a mutated form of the protein huntingtin. This increases the decay rates of certain types of neurons
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What is often the first sign of Wilson's Disease?
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cirrhosis of the liver (it is the first organ affected by the disease) - peak prevalence at age 10-13
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What are the neurological and psychiatric symptoms of Wilson's disease, and when do they typically peak?
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age 19-20
asymmetrical tremor ataxia - balance difficulties walking, talking, swallowing dystonia - spastic, repetitive abnormal movements entailing a rigid, sustained muscle contraction involving the arm, leg, neck, eyes, face, hand; sometimes involuntary painful movements and abnormal postures grand mal seizures hallucinations, manic excitement, depression |
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What are the interesting names for a few dystonic features of Wilson's Disease?
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risus sardonicus - smile
torticollis - neck twisting |
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Who linked Wilson's Disease to a problem with copper metabolism?
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JN Cumings, 1948
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How does copper metabolism problems affect patients with Wilson's disease?
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low level of ceruloplasm in blood serum - because copper is not being easily incorporated
high copper in 24 hrr urine sample and liver bipsy Kaser-fleischer rings around eyes |
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What is used to treat Wilson's Disease?
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chelating agents (penicilamine) - discovered by John Walshe
Trientine (Syprine) now preferred for chelation - does not exacerbate neurological symptoms Zinc acetate (Galzin) to inhibit copper absorption diet - avoidance of copper-containing foods (chocolate, liver, nuts, mushroom, shellfish) |
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What is the genetic pattern of Wilson's Disease? (discovered 1953)
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autosomal recessive
gene ATP7B on chromosome 13 no genetic test spontaneous mutation can occur |
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How does copper affect the pathology of Wilson's Disease patients?
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copper deposits damage the corpus striatum, especially the putamen; damage to the tracts projecting between the striatum and the prefrontal cortex, atrophy in the thalamus and diffusely throughout cerebrum and cerebellum
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What is responsible for the metabolic problem involving the elimination of copper in Wilson's Disease patients?
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ATP7B that links copper to ceruloplasmin and releases it into the bloodstream, as well as removing excess copper by secreting it into bile. Both functions of ATP7B are impaired in Wilson's disease. Copper accumulates in the liver tissue; ceruloplasmin is still secreted, but in a form that lacks copper (termed apoceruloplasmin) and rapidly degraded in the bloodstream
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What is P-type copper-transporting ATPase?
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?
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