Cedrick
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a 2year old boy has brittle despigmented hair,cerebral atrophy,delayed myelination,motor delay and mental retardation
lysyl oxidase activity is decreased
the funtion of which of the following substance is most likely to be defective in this patient ?
a.-albumin
b.-ceruloplasmin
c.-chondroitin sulfate
d.-collagen
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| Leopard
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Collagen
Lysyl oxidase associate with
- Collagen synthesis
- Cu++ is a co-factor
- Blocked in Homocysteinuria
- its complete deficiency is called ED type VI
Best of luck
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| Cedrick
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good job
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| drpkaur
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collagen right.
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| fox
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I think answer is B. Here's the reference: (e-medicine)
In Menkes kinky hair syndrome, intestinal copper uptake by brush border cells is normal, but copper transport to other tissues is affected. This change alters the activities of various copper-dependent metalloenzymes. Male infants who are affected typically die by the time they are aged 2-3 years. Carrier female patients may have only a hair-shaft abnormality (ie, pili torti).
Pathophysiology: A defect in intestinal copper transport with associated low serum copper and ceruloplasmin levels results in a deficiency in copper-dependent enzyme activity. Copper-dependent metalloenzymes relevant to the clinical phenotype include tyrosinase (pigmentation of skin and hair), lysyl oxidase (elastin and collagen cross-linking), ascorbate oxidase (skeletal development), monoamine oxidase (possibly responsible for pili torti), superoxide dismutase (free-radical detoxification), dopamine beta-hydroxylase (catecholamine production), peptidyl-glycine alpha-amidating mono-oxygenase (bioactivation of peptide hormones), and cytochrome c oxidase (electron transport and possibly responsible for hypothermia). The resulting defects are reflected in the clinical phenotype.
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| Leopard
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Fox
Bravo!!!!!!!!!!!!!!!!!
Well caught and well said and thanks a lot
I think your idea is correct .I appreciate your contribution ,otherwise mental changes cannot be explained.Honestly speaking I had idea the ceruloplamin is changed in Wilson ,but had no idea that it in Menke ceruloplasmin is affected.
,Best of luck
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| fox
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I knew all along that it was menke's but didnt wanna post it without reference as the ever alert leopard is a no-nonsense guy/gal, always asking for reference! http://www.prep4usmle.com/forum/templates/default...
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| docarchana
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there was a long discusssion for this q previously whether the ans is B or D and finally settled as collagen. if i can find the link i shall post it her. but for now i think the reason given by fox is right and hence ceruloplasmin is the ans.
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| Leopard
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The evidence produced by FoX is so strong that appealled me a lot.We should not hesitate to accept the facts because all of us are here to help and share our knowledge and findings.Anyone of us can commit mistake.But when reference comes then that can be refuted either by reference or very strong logic. And you know FOX is famous for being extraordinary WISE and INTELLIGENT.That proved today.
Best of luck
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| docswapna
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by fox post, ceruloplasmin is the right ans
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| klimt
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B indeed. Menkel's disease
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