31 terms

Porphyria Quiz

STUDY
PLAY
Porphyrins
chemical intermidiates in the synthesis of hemoglobin, myoglobin, and other respiratory pigments called cytochromes
Iron is chelated with porhyrins to form
heme
Porphyrins are analyzed in clinical chemistry to diagnose
porphyrias
Porhyrins are
stable compounds, red-violet to red-brown in color, that fluoresce red when excited by light near 400 nm
Clinically significant porphyrin compounds
-protoporphyrin (PROTO)
-uroporphyrin (URO)
-coproporphyrin (COPRO)
porphyrinogens
reduced forms of pophyrins, highly unstable, colorless, do not fluoresce
porphyrias
inherited or acquired enzyme deficiencies, that result in overproduction of heme precursors
porhyrias result from over production of heme precusors in the
bone marrow (erythropoietic porphyrias [`EPs}) or the liver (hepatic porphyrias)
URO is excreted primarily in the
urine
Proto is excreted primarily in the
feces
COPRO is excreted
in either depending on rate of formation of urine and it's pH
All porphyrias are inherited as
autosomal dominant (one gene affected)
deficiency porphyria (ADP) and congenital erythropoietic porphyria (CEP) are inherited as
autosomal recessive
ALA synthase is the
rate limiting step
ALA dehydratase ALAD
neuropsychiatric symptoms
deficiency porphyria ADP
neuropsychiatric symptoms
acute intermittent porphyria AIP
neuropsychiatric symptoms
porphyria cutanea tarda PCT
cutaneous symptoms
hepatoerythropoietic porphyria HEP
cutaneous symptoms
erythropoietic porphyria EP
cutaneous symptoms
congenital erythropoietic porphyria CEP
cutaneous symptoms
hereditary coproporhyria HCP
neurocutaneous symptoms
variegate porphyria VP
neurocutaneous symptoms
neuropsychiatric symptoms
abdominal pain, vomitting, constipation, tachycardia, hypertension, psychiatric symptoms, fever, leukocytosis, and paresthesia
cutaneous symptoms
photosensitivity, blisters, excess facial hair, and hyperpigmentation
Inherited ADP
autosomal recessive, extremely rare, affected ALAD gene is located on chromosome 9q33.1
Increased urinary coproporphyrinogen III occurs in inherited ADP, but may also occur in
lead poisoning (most common cause of low ALAD activity
ADP may be distinguished from lead poisoning by
in vitro addition of dithiothreitol or other sulfhydryl reagents (restores activity of erythrocytes in those with lead poisoning, no change in those with ADP
AIP
enzyme deficiency of enzyme hydroxymethybilane synthase, higher prevalence in scandanavian countries, drugs most commonly precipitate the cause of disease (barbituates, sulfonamides)
CEP
deficiency of uroporphyrinogen III cosynthase, one of the rarest porphyrias, Gunther's disease, teeth will fluoresce red under ultra violet light, red-brownish discoloration under normal light
PCT
the most common porphyria