SectionIIG Flashcards
(49 cards)
Mutations in the gene encoding what enzyme is resposible for classic galactosemia?
-mutations in galactose-1-phosphate uridyl transferase (GAL-1-P uridyl transferase)
What does dysfunction of GAL-1-P uridl transferase cause?
- inability to convert galactose to glucose
- galactose is instead converted to galactilol and galactonate
What are the symptoms of classic galactosemia?
- failure to thrive
- Jaundice (hepatic insufficiency)
- cataracts
- later groeth failure mental retardation
What is the tratment goal fo classic galactosemia?
-reduce the amout of dietary galactose
What enzyme is difficient in Von Gierk’s disease?
-glucose-6-phosphatase
What are the results of a loss of function in g-6-phosphatase?
- no breakdown of glycogen in the liver
- leads to hepatomegly and hypoglycemia
What enzyme is deficient in hereditary fructose intolerance?
-fructose 1,6-bisphosphate
When is HFI usually noticed? What are the symptoms?
When the child is weaned from breast feeding to some kind of fruit (JUICE IS A BUZZWORD)
-poor feeding, failure to thrive, hepatic and renal insufficiency
What is the best mode of treatment for HFI?
limit the intake of fructose!
What enzyme is defective in penylketonuria (PKU)?
-Phenylalanine hydroxylase
What is the most important factor in diagnosis of PKU?
Early detection in order to prevent mental retardation.
What does the excess phenyalanine in PKU do to the CNS?
-It disrupts myelination, and protein synthesis
What enzyme is difficient in MSUD? What is the result?
- defect in branched chain alpha-ketoacid dehydrogenase which leads to and accumulation of branched chain amino acids.
- lead to neurodegeneration
What is the treatment of MSUD?
dietary restriction of BCAAs
What can be administered to boost the activity of BCKAD?
Thiamine
What is deficient in MCAD dificiency and what is the result?
- medium chain acyl-coenzyme A dehdrogenase (MCAD)
- results in a buildup of fatty acid intermediates during fasting which has profound effects on the CNS.
- results in episodeic hypoglycemia after a fast.
What is the treatment for an MCAD dificiency?
-avoidance of fasting.
What enzyme is dificient in congenital adreanal hyperplasia (CAH)?
21-hydroxylase
What is the major effect in CAH?
the block in corticosteroid synthesis will lead to:
- virulization of females in urtero
- salt loss form causes weight loss, lethargy and dehydration in males
Why does CAH cause hyponatremia and androgen production?
- loss of 21-hydroxylase sends cortisol precusors down other pathways resulting in production of androgens.
- lack of aldosterone production results in a lack of Na+ reuptake in the kidneys which causes hypokalemia, hyponatremia, and therefore renal crisis.
What is the treatment for CAH?
-replace that Cortisol!
What are the symptoms of Zellwegger Disorder?
-neonatal hypotonia, progressive white matter disease, distinctive face, death in infancy
What causes most lysosomal disorders?
enzyme deficiencies
What is the cause of MPS (mucopolysaccharidoses) disorders?
-reduced ability to degrade glycosaminoglycans
