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Old 07-17-2013
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Neuro Phenylketonuria Effects On the Brain

In PKU we see that accumulation of toxic metabolites of phenylalanine causes mental retardation.
The question is that why other regions of brain are not affected by these metabolites? for example why visual cortex is not influenced in this disease? or why neuroglia cells are intact in this case?
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Old 07-20-2013
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can anybody help me with this question please?
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Old 07-20-2013
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perhaps because that's just the way it is. certain things affect certain parts of the body. it just so happens, that the metabolites that accumulate in PKU happen to be injurious to the brain, and that the injury results in mental retardation. enough said about that.
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Old 07-20-2013
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Quote:
Originally Posted by ReggieMiller View Post
perhaps because that's just the way it is. certain things affect certain parts of the body. it just so happens, that the metabolites that accumulate in PKU happen to be injurious to the brain, and that the injury results in mental retardation. enough said about that.
U will see defects in areas that use phenylalanine... Its that simple... Pla gives tyrosine which gives various monoamines.... So areas like locus cerulus , substantia nigra etc will have defects... Also same reason for albinism... So apparently things are not just so
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Old 07-20-2013
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Quote:
Originally Posted by ReggieMiller View Post
perhaps because that's just the way it is. certain things affect certain parts of the body. it just so happens, that the metabolites that accumulate in PKU happen to be injurious to the brain, and that the injury results in mental retardation. enough said about that.
Thanks for your answer .But I don't understand that why other parts of the brain are intact ? these metabolites can accumulate in other regions and disrupt the normal function of those cells .
why other cells of our body don't show signs of this disease or show milder symptoms ?
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Old 07-20-2013
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Originally Posted by aman_j View Post
U will see defects in areas that use phenylalanine... Its that simple... Pla gives tyrosine which gives various monoamines.... So areas like locus cerulus , substantia nigra etc will have defects... Also same reason for albinism... So apparently things are not just so
No ! other cells use phe to synthesize proteins . they need this amino acid for the normal functions of the cell . don't they???
after uptake of this amino acid by the cells the excessive metabolites of phe can disrupt the cellular functions .
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Old 07-20-2013
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Originally Posted by Ardavan View Post
No ! other cells use phe to synthesize proteins . they need this amino acid for the normal functions of the cell . don't they???
after uptake of this amino acid by the cells the excessive metabolites of phe can disrupt the cellular functions .
Yes very correct but the point is there is only ONE enzyme defect... In the other areas it may be used up in some other pathways.... So the defective pathway using sites suffer
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Old 07-20-2013
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http://bh4.org/pdf/degroot_2010_mgm.pdf

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In summary, we hypothesize that the main pathophysiologic mechanisms of cognitive dysfunction in PKU are reduced cerebral neurotransmitter and protein synthesis, caused by impaired brain uptake of non-Phe LNAA in the presence of elevated plasma Phe concentrations. Clearly, more research is needed to investigate these mechanisms in more detail.
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Biochemistry-, Nervous-System-, Pathology-

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