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29 Cards in this Set
- Front
- Back
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What gene is mutated in oculocutaneous albinish? |
Tyrosinase - OCA1 |
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What does OCA1 control? |
Controls synthesis of melanin within melanocytes |
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What does melanin do to eyes? |
Lack of melanin in the eye causes poor vision |
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What is sphingolipidoses? |
Lipid storage disease |
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1. What type of inheritence is sphingolipidoses? 2. What gene does it affect? 3. What does the gene code for? |
1. Autosomal recessive mutation 2. HEXA gene on chromosome 15 3. Encodes hexosaminidase A |
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What does a mutation in the HEXA gene result in? |
Results in the inability to degrade splingolipid which leads to deposition of lipid and glycolipid gangliosides in the brain, liver and spleen |
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What the major types of glycogen storage disorders? Give a brief description of each. |
1. Von Gierke - G6P accumulation 2. Cori - Deficiency in branching enzyme 3. Anderson - Results in catabolism resistant glycogen 4. Hepatic Phosphorylase deficiency - Glycogen degradation problems 5. Pompe - Cannot breakdown glycogen = muscle weakness 6. Mc Ardle - Deficiency in muscle phosphorylase required for muscular glycogen degradation |
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What is Anderson disease? |
A glycogen storage disorder. It is a branching enzyme deficiency which results in liver failure |
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Why does Hepatic phosphorylase deficinecy result in an increase in liver size? |
Glycogen not degraded so liver expands |
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What is the difference between Mcardle and Pompe glycogen disorders and other glycogen disorders? |
1. Pompe & Mcardle affect muscles 2. The rest affect the liver |
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What is the classic x linked disease? |
Haemophilia |
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Name 3 common X linked disorders. |
1. Color blindness 2. Haemophilia A & B 3. Muscular dystrophy |
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What is the salvage synthesis pathways? |
The pathway of cellular recycling. Which involves the production of GMP to ultimately produce AMP. |
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What enzyme drives the salvage synthesis pathway? |
Hypoxanthanine guanine phosphoribosyl transferase (HPRT) |
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What is Lesch Nyhan syndrome? |
Deficiency in hypoxanthanine guanine phosphoribosyl transferase (HPRT) leading to wastage of cellular breakdown products. The products degrade and lead to increased uric acid. |
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What is the result of HPRT deficiency? |
Lack of purines which are usually obtained from salvage synthesis means that de novo purine synthesis pathway is regulated due to build up of excess PRPP |
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What does upregulation of the de novo purine synthesis pathway result in? |
1. leads to excess uric acid production which severely affects the CNS. |
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How is Lesch-Nyhan syndrome treated? |
Treat with uric acid reducing drug Allopurinol |
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What is the main disease referring to a disorder of copper metabolism? |
Menkes disease |
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What is the gene failure in Menkes disease? |
Mutation in ATP7A gene on the X chromosome |
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What is the role of lysyl oxidase? |
A cupro enzyme responsible for cross linking collagen and elastin |
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What gene is disrupted in huntington's disease? How is it disrupted? |
HTT gene disrupted due to expansion of the CAG (glutamine) triplet repeats at the 5' end of the HTT locus.. |
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What is the result of the huntington gene mutation? |
Progressive degeneration of brain tissue - THe neural ganglia |
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What confers a normal number of CAG repeats in HTT? |
<34 CAG repeats |
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What is anticipation? |
In huntington's disease, more CAG repeats are extended in the offspring of those affected. Severity increases in the next generation. |
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Why is huntington's also called the polyglutamine disease? |
HTT gene encodes a polyglutamine - huntingtin |
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What is the main culprit in gamete formation for extension of the triplet repeat? |
Spermatogenesis results in higher likelihood of extending the triplet repeat. |
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Name an autosomal dominant lipid metabolism disorder? |
Familial Hypercholosterolemia |
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Why doesFamilial Hypercholosterolemia occur? |
Due to defective LDL receptors leading ot increased levels of endogenous cholesterol synthesis. |
