Term
| Peroxisomal catabolic function |
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Definition
beta oxidation of very long chain fatty acids
glyoxylate/glycolate metabolism
phytanic acid oxidation
hydrogen peroxide metabolism |
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Term
|
Definition
| important ether phospholipid constituent of myelin and cell membranes, especially in CNS |
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Term
| platelet activating factor |
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Definition
| involved in glutaminergic signaling ether phospholipid |
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Term
|
Definition
alkaline pH
encoded on nuclear genes, are translated on polyribosomes
selectively imported into pre-existing peroxisomal membranes |
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Term
| Peroxisomal transport signals |
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Definition
mediated by peroxisomal targeting signals in the primary peptid sequence
PTS1- carboxy signal
PTS2- amino terminal signal |
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Term
| Peroxisome Biogenesis Disorders Consequences |
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Definition
peroxisomes absent or reduced in #
catalase in cytosol
decreased levels of plasmalogens
increased levels of VLCFA
increased urinary excretion of dicarboxylic acids |
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Term
| Peroxisome Biogenesis Disorders def |
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Definition
reduced amount of peroxisomes
primary defects in these disorders are in peroxisomal integral membrane proteins required for recognition and proper import of enzymes into thep eroxisome |
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Term
| Zellweger Syndrome spectrum |
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Definition
peroxisome biogenesis disorder
most severe
present at birth with severe hypotonia
poor feeding, liver dysfunction
bony stippling, seizures
die within one year of life |
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Term
| Neonatal adrenoleukodystrophy |
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Definition
milder form of zellweger syndrome
can present later |
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Term
| Infantilte Refsum disease |
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Definition
milder form of zellweger syndrome
can present later |
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Term
| Rhizomelic chondrodysplasia punctata Type 1 |
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Definition
Peroxisomal Biogenesis Disorder
primary defect is in the mutation in the Pex7 gene
affect import of a subset of matrix enzymes while leaving others intact
severe disproportionate shortening of proximal limbs
microcephaly, cataracts, psy retard |
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Term
| Pex7 gene in perioxisomes |
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Definition
| encodes the receptor for a subset of peroxisomal matrix enzymes that contain the PTS2 targeting signal |
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Term
| Anabolic Peroxisomal Functions |
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Definition
biosynthesis of ether phospholipids
cholesterol & bile acid biosynthesis |
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Term
| Peroxisomal Specific Enzyme Deficiencies |
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Definition
Normal peroxisomes
Single Enzyme deficiency |
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Term
| Examples of Peroxisomal Specific Enzyme Deficiencies |
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Definition
acatalasemia
hyperoxaluria type 1
3-oxoacyl-CoA thiolase deficiency
Acyl-CoA oxidase deficiency
Bifunctional enzyme deficiency |
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Term
| X-linked adrenoleukodystrophy |
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Definition
single gene peroxisomal deficiency
normal early development with rapid downhill course
hyperactive, visual+hearing impairment, neurologic disorder, adrenal insufficiency, abnormal accumulation of VLCFAs
molecular diagnosis- ABCD1 gene |
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Term
| treatment of X-linked ALD |
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Definition
manage adrenal insufficiency
bone marrow transplant for cerebral form
dietary therapy "lorenzo's oil" |
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Term
|
Definition
normalizes the levels of VLCFAs
efficacy still not clear; benefict limited |
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