metabolism Flashcards
homogentisate oxidase deficiency
alkaptonuria
benign disorder of tyrosine metabolism (blocks metabolism of phenylalanine and tyrosine at the level of homogentisic acid–> prevents conversion of tyrosine to fumarate)
pigment forming homogentisic acid accumulates in tissue
what is diminished in hyperammonemia of hepatic encephalopathy or urea cycle enzyme deficiencies?
alpha ketoglutarate and glutamate (glutamine is high)
B12 deficiency
can lead to a folate trap–> impaired synthesis of methionine and sometimes homocysteinuria (because reaction pushed in the other direction)
G6PD deficiency
cant complete HMP shunt, so decreased NADPH concentration; decreased NADPH in RBCs–> decreased glutathione reduction–> less detoxification of free radicals and peroxides–> hemolytic anemia
galactose-1-phosphate uridyltransferase deficiency
classic galactosemia; damaged caused by accumulation of toxic substances (not just galacitol)
HGPRT deficiency?
defective purine salvage
medium chain acyl-CoA dehydrogenase deficiency
disorder of fatty acid oxidation –> cant break down fatty acids into acetyl-CoA–> accumulation of 8-10 carbon fatty acyl carnitines in the blood and hypoketotic hypoglycemia
fructokinase deficiency
essential fructosuria
ALTERNATE METABOLIC PATHWAY: increase of fructose-6-phosphate (via hexokinase activity)–> metabolized in glycolytic pathway or converted to G6P
lipoprotein lipase deficiency
familial dyslipidemia type I- hyperchylomicronemia
increased chylomicrons, triglycerides, cholesterol
LDL receptor deficiency or defect
familial dyslipidemia type IIa- family hypercholesterolemia
increased LDL, cholesterol
hepatic overproduction of VLDL
familial dyslipidemia type IV- hypetriglyceridemia
increasedV LDL, triglycerides
aldolase B deficiency
fructose intolerance
increased concentration of fructose-1-phosphate–> decreased available phosphate and inhibition of glycogenolysis and gluconeogenesis; sxs after consuming fruit, juice or honey
galactokinase deficiency
galacitol accumulates in the blood if galactose is present; mild condition
cystathione synthase deficiency
homocystinuria
decreased cystathionine synthase affinity for pyridoxal phosphate
homocystinuria
homocysteine methyltransferase deficiency
homocystinuria
systemic primary carnitine deficiency
inherited defect in transport of long-chain fatty acids into the mitochondria–> toxic accumulation
alpha-ketoacid dehydrogenase
MSUD
blocked degradation of branched amino acids (isoleucine, leucine, valine)
deficiency
pathophys
phenylalanine hydroxylase deficiency
PKU
excess phenylalanine–> excess phenylketones in urine
PDH complex deficiency?
pyruvate can’t enter glycolysis/TCA cycle so is converted to lactate and alanine instead
n-acetylglutamate synthase deficiency
required cofactor for carbamoyl phosphate synthetase I–> can’t do urea cycle–> hyperammonemia
