Inborn Errors of Metabolism/Aminoacidurias Flashcards
Cystinuria (and cystinosis) is _____ and is tested with _____.
An increase in cysteine. Cyanide nitroprusside.
Cystinosis
Intracellular deposition of cysteine within lysosomes.
Sx include Polyuria, Polydipsia, Dehydration, Vomiting
_____ readily pass through glomerular filtration barrier and are reabsorbed in the proximal tubule.
Amino acids
Maple Syrup Urine Disease
BCKA (keto-acids) – eg, Leucine, Isoleucine, Valine increase in blood, CSF, urine
Prenatal and neonatal screening commonly detect MSUD
Cystic Fibrosis
AR disease affecting lungs, pancreas, liver, kidney, intestine. Sweat tests (collection and measurement of sweat), newborn screening, genetic tests are used to test for CF
An AR genetic disease that causes difficulty breathing and lung infections due to mucus buildup
Cystic fibrosis affects _____.
mostly the lungs but also pancreas, liver, kidneys, intestines
CF requires _____ faulty genes. Chloride ions in CF _____.
2 faulty genes
Cl- ions are blocked from leaving lung cells due to missing or mutated CFTR
CFTR
Cystic fibrosis transmembrane (conductance) regulator
Hartnup Syndrome
Pellegra-like dermatosis. Affects absorption of nonpolar amino acids – eg, tryptophan
PKU
Phenylalanine buildup in blood from a lack of phenylalanine hydroxylase.
Tyrosinosis/Tyrosinemia
Defect in fumarylacetoacetase (tyrosine levels increase in blood and urine)
Laboratory test for tyrosinosis
Ion-exchange column chromatography
Results of tyrosinosis
Liver failure, rickets, renal tubular dysfunction and polyneuropathy
First discovered inborn error of metabolism
Alkaptonuria
In alkaptonuria, urine, plasma, cartilage, and connective tissue can turn
Black
Homocysteinuria is an excess of
Homocysteinuria is a deficiency of
Why is homocysteinuria difficult to measure?
homocysteine in urine
cystathionine beta synthase
Difficult to measure (bound to other thiols)
MSUD
Maple Syrup Urine Disease: Rare genetic disorder involving deficiency of branched chain alpha keto acid dehydrogenase complex
MSUD is a buildup of
Leucine, Isoleucine, Valine
MSUD uses a modified _____.
Guthrie test that detects elevated plasma Leucine
Alkaptonuria is an accumulation of _____ due to _____.
Homogentisic acid (HGA) accumulation due to homogentisate oxidase
Problems resulting from alkaptonuria (3)
Heart problems, kidney stones, prostate stones
Ochronosis
Buildup of black pigmentation in connective tissue.
Tryptophan can be converted into _____, _____, and _____.
5 HT, melatonin, niacin
Proximal tubular cells are unable to reabsorb amino-acids in this condition
Cystinosis
Most common cause of Fanconi syndrome (inadequate reabsorption by proximal renal tubule).
Cystinosis
Most metabolic disorders are _____ (genetically).
Autosomal recessive
