Metabolic Disease Flashcards
Result from disruption of a normal metabolic pathway that causes increased plasma concentrations of arz the non-metabolized substances; over ride reabsorption ability of the tubules are not normally reabsorbed from the filtrate
Overflow
Due to defective tubular reabsorption of amino acids
Renal
Tubules in
the nephron are no longer reabsorbing certain amino acids
Renal
Failure to inherit a gene that codes for a particular enzyme
Inborn error of metabolism
Testing for many substances is now performed using
Tandem Mass Spectrophotometry
It is capable of screening infant blood sample for specific substances associated with particular IEMs
Tandem Mass Spectrophotometry (MS/MS).
Homogentisic acid color
Black
Affect the color tho not directly
Melanin
Indican color
Dark/bluish color
Porphyrins color
Pink to reddish brown or purple
Most well known of the aminoacidurias
Phenylketonuria
Most well known of the aminoacidurias
Phenylketonuria
Phenylketonuria: negative for the gene that codes for?
Phenylalanine hydroxylase
Phenylketonuria: negative for the gene that codes for
Phenylalanine hydroxylase
Screnung test for pku
FeCl3 tube tes
Phenistix strip
Pku: FeCl3 positive color
Blue green color
Pku: phenistix color
Gray to gray green color
GBIT: B.subtilis is cultured with?
Beta-2-thienylalanine (TE)
counteracts the action of B2-TE
Phenylalanine
Guthrie bacterial inhibition test aka
Guthrie’s microbial inhibition assay
Most well known teit for phenylketonuria
Guthrie bacterial inhibition test’
Blood sample from the heel stick and placed on filter paper disc
• placed in culture media incorporated with Beta-2-thienylalanine which serves as an inmoitor for B-subtilis
(+): Growth of the organism
Guthrie bacterial inhibition test’
accumulation of excess tyrosine in the plasma (tyrosinemia)
producing urinary overflow
Tyrosyluria
Tyrosyluria: (-) for a gene that decodes for:
Type 1:
Fumarylacetoacetate hydrolase (FAH)
Tyrosyluria: (-) for a gene that decodes for:
Type 2:
Tyrosine aminotransferase
Tyrosyluria: (-) for a gene that decodes for:
Type 3:
p-hydroxyphenylpyruvic acid dioxygenase
• May also be seen in patients with severe liver disease (will produce tyrosine and leucine crystals)
Tyrosyluria
Tyrosyluria odor
Rancid butter odor
Screening for tyrosyluria
Nitrosonaphthanol
Tyrosyluria confirmatory test
Chromatography
Deficiency in homogentisic acid oxidase
Alkaptonuria
Increased homogentisic acid
Alkaptonuria
Produces brown pigment deposits in body tissues that
can lead to arthritis, and liver and cardiac problems.
Homogentisic acid in Alkaptonuria
Screening test for alkaptonuria
Ferric chloride tube test
• Benedict’s test
• Alklinization of fresh urine
Increased urinary melanin that produces a darkening of urine
Melanuria
Indicates malignant melanoma
Melanuria
Urine color in melanuria
Black urine
Screening for melanuria
Screening:
• FeCl tube test
• Sodium nitroprusside test
• Ehrlich test
The branched-chain amino acids differ from other amino acids by having a______ that branches from the main aliphatic carbon chain
methyl (-CH3) group
Two major groups of branched chain aminoaciduria
Two major groups:
Accumulation of one or more of the early amino acid degradation products (ex MSUD*
Accumulation of organic acids produced further down in the amino acid metabolic pathway -Organic acidemias /
Clinical findings of Branched-Chain Aminoacidurias
Ketonuria
Organic acidemias
Isovaleric Acidemia
Propionic Acidemia
Methylmalonic Acidemia
Most common IEM in the Philippines
Maple syrup urine disease
MSUD: negative Gene that codes for the enzyme for metabolism of the ketoacids of
Leucine, isoleucine, valine
Causes severe mental retardation, convulsions, acidosis, and
hypoglycemia if untreated
- Death occurs during first year
MSUD
Screening for msud
Screening:
• 2,4-dinitrophenylhydrazine
• FeCl3 tube test
Organic acidemia general symptom
Hypoglycemia
• Ketonuria; and
• increased serum ammonia
Most commonly encountered disorders: organic acidemias
Isovaleric acidemia
Propionic axidemia
Methylmalonic acidemia
Increased urinary excretion of the metabolites indican and 5-
hydroxyindoleacetic acid
Tryptophan Aminoaciduria
Usually seen in cases of argentapenoma where there is an
Tryptophan Aminoaciduria
which is a metabolite in
serotonin
5-hydroxyindoleacetic acid
Increased amounts of tryptophan are converted to indole
Indicanuria
Seen in intestinal disorders
Indicanuria
blue diaper syndrome - rare inherited
disorde
Hartnup disease
Indicanuria urine color
Indigo blue
Indicanuria factors
Obstruction
• Presence of abnormal bacteria
• Hartnup disease
Screening test for indicanuria
Obermayer’s test
Degradation product of serotonin
5-hydroxyindoleacetic acid
Serotonin is produced
from tryptophan by—- in the —
Argentaffin cells in the intestine
Argentaffin cell tumors
5-hydroxyindoleacetic Acid
- A condition marked by elevated amounts of the amino acid
cystine in the urine - Due to the inability of the renal tubules to reabsorb cystine
filtered by the glomerulus
Cystinuria
Cystinuria defective reabsorption of what?
Cystine, ornithine, leucine, arginine
Cystinuria odor
Sulfur odor
(-) gene that codes for an enzyme responsible for cystine
metabolism
- Cystine deposits in many areas of the body (BM, cornea,
Lymph nodes, and internal organs)
Cystinosis
Test for cystinuria and cystinosis
Brand’s modification of Legal’s nitroprusside test
Rgt of Brand’s modification of Legal’s nitroprusside test
Cyanide nitroprusside
Defect in the metabolism of the amino acid methionine
Homocystinuria
Homocystinuria is negative for that gene that codes for the enzyme
Cystathione beta synthase
Accumulation of incompletely metabolized polysaccharide
portions in the lysosome
Mucopolysaccharide Disorders
mucopolysaccharides accumulate in the cornea;
skeletal structure abnormality and severe mental retardation
Hurler
skeletal structure abnormality and severe mental
retardation
Hunter
mental retardation only
Sanfilippo
White turbidity
Cetylmethylammonium bromide twst
massive excretion of uric acid crystals
in the urine caused by the failure to inherit the gene to
produce hypoxantine guanine and
phosphoribosyltransferase; “orange sand” in diaper
Lesch nyhan disease
