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24 Cards in this Set

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What is the pH optima of hydrolytic enzymes?
pH 4-6
How are lysosomal enzymes modified to ensure that they are targeted to lysosomes?
They are tagged with a mannose-6-phosphate marker.
What is the "official" name of I-cell disease? (what material is stored?)
Mucolipidosis II
What enzyme is deficient in I-cell disease, and what does it do normally?
N-acetyl-glucosaminyl-phosphotransferase, modifies the lysosomal enzymes with mannose-6-phosphate.
What is the diagnosis of I-cell disease?
Increase of lysosomal enzymes extracellularly; very low levels intracellulary.
What are the clinical findings in I-cell disease?
Severe because with symptamology from multiple enzyme deficiencies. Patients have progressive failure to thrive, coarse facial feature, gingival hypertrophy, macroglossia, severe psychomotor retardation usually apparent by 6 mos. Death by age 5-7.
What are the two sphingolipidoses?
Tay-Sachs and Gaucher disease.
What enzyme is deficient in Tay-Sachs disease?
hexosaminidase A
Which subunit of hexosaminidase A is affected in Tay-Sachs disease?
The α-subunit.
What is the clinical picture of infantile TSD?
Clinical findings are totally neurological. Patients are normal or 3-5 mos, then there is a severe neurologic deterioration with progressive weakness, loss of any attained motor skills, loss of vision, seizures, macrocephaly and death by age 2-4 years.
What enzyme is deficient in Gaucher disease, and what molecule accumulates where?
β-glucocerebrosidase, glucocerebroside accumulates in reticuloendothelial cells (macrophages)
What are the three clinical classifications of Gaucher disease?
Type I - non-neuronopathic
Type II - acute neuronopathic
Type III - subacute neuronopathic
What are mucopolysaccharides (MPS)?
Long, unbranched polysaccharide chains of repeating disaccharide units, one of which is always an amino sugar.
What are the major MPSs stored in diseased states?
Heparan sulfate
Keratan sulfate
Dermatan sulfate
What are the general findings of MPS disease?
bone involvement, coarse facial features, organomegaly, progressive mental retardation
Prior to defining the enzyme defects, how were the disorders classified?
Via complementation (cross-correction)
What is the most classical MPS disease?
Hurler Syndrome (MPS I)
What is the main difference in MPS I (Hurler) and MPS II (Hunter)?
MPS II does not involve corneal clouding.
What is the name given to MPS III?
San Filippo syndrome
Which MPSs are stored in MPSs I and II?
Heparan sulfate and dermatan sulfate.
What MPS is stored in MPS IV?
Keratan sulfate
What MPS(s) is/are stored in MPS III?
Heparan sulfate only
Which MPS is stored in MPS IV?
Keratan sulfate (this is the only disorder storing keratan sulfate)
Which disorder/disease presents with "cherry red spots"?
Tay-Sachs disease