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43 Cards in this Set
- Front
- Back
what does the term xeroderma mean
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atrophic and dry
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skin damage to patients with xeroderma pigmentosa results from which energy source
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ultra-violet light
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what is the most likely outcome in a patient with xeroderma pigmentosa
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2/3 die from metastatic dermatological cancer before adulthood
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which is the common defect in xeroderma, Cockayne syndrome, and trichothiodystrophy
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defect in nucleotide excision repair
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which part of the nucleotide excision repair process is most affected in individuals with complementation group A
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DNA damage recognition
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in nucleotide excision repair, the global genome repair pathway starts out with the action of which of the following gene products
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XPC/HR23B
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which gene products carry out the final steps of nucleotide excision repair
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DNA pol delta/epsilon and ligase
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the mean patient age for development skin cancer in a patient with xeroderma pigmentosa
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8 years
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the mean age for developing skin cancer in patient with Cockayne syndrome
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same as in the general population
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how is the diagnosis of a specific XP complementation group defect established
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assay of unscheduled DNA synthesis in UV-irradiation cultured fused fibroblasts
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which finding is most characteristic of gout in a 45-year old man with recurrent arthritis for over two decades
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tophi on ear cartilage
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which test is the most indicative of a hyperuricemia related arthropathy
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negative birefringent intracellular cystals in joint fluid aspirate
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which mechanism would most likely account for recurrent gout in a 62 year old man
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increased URAT1 activity
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a joint tape from a tender and swollen tow in a man that awakened from sleep the night after excessive drinking would likely show which cellular feature on microscopy
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predominance of polymorphonuclear neutrophil leukocytes with no bacteria
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an 18 year of with recurrent arthritis is diagnosed with hyperuricemia secondary to an enzyme defect, which enzyme is most responsible for this clinical manifestation due to a low Km value for the defective enzyme
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phosphoribosylpyrophosphate synthetase
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which enzyme defect is associated with Lesch-Nyhan syndrome
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hypoxanthine-guanine phosphoribosyl transferase deficiency (HGPRT)
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9 month old with delay in developmental milestones, dystonia, chorea and uric acid is elevated. what is the inheritance pattern most likely
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x-linked recessive
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what type of person has the highest likelyhood for developing gout
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65 year old man
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de novo purine synthesis is most dramatically stimulated by which substance
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alcohol
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27 year old man with sickle cell anemia develops left ankle arthritis. joint aspirate demenonstrates negatively birefringent crystals. what is the best management plan after NSAID therapy
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hydroxyuria to diminished hemolysis
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which enzyme of heme biosynthetic pathway is depressed to 50% of normal levels in acute intermittent porphyria
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porphobilinogen deaminase
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which enzyme of the heme biosynthetic pathway is subject to feedback inhibition by heme
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ALA synthase
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which intermediates of the heme biosynthetic pathway accumulate in acute intermittent porphyria (2)
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ALA
prophobilinogen |
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what is the most frequent symptom of an acute attack of acute intermittent porphyria
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abdominal pain
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administration of which substrate is useful in treating mild attack of acute intermittent porphyria
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glucose
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attack of acute intermittent can be provoked by ingestion of alcohol due to induction of what enzyme depleting the liver heme pool
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cytochrome P450
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what is needed for porphyrin synthetsis
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Glycine
Succinyl-CoA Vitamin B6 |
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what two enzymes do lead inhibit in heme synthesis
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ALA dehydratase
ferrochelatase |
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how many ALA molecules condense to form one porphyrin ring
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8
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what is incorporated into the protoporphryin IX to make heme
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iron
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what clinical manifestations differentiate acute and cutaneous porphyrias
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acute - neurologic effects
cutaneous - photosensitivity |
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uroporphyrinogen decarboxylase deficiency
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porphyria cutanea tarda
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porphobilinogen deaminase deficiency
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acute intermittent porphyria
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ferrochelatase deficiency in the erythtropoietic cells
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ferrochelatase
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major clinical feature of porphyria cutanea tarda
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skin photosensitivity
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clinical manifestations of acute intermittent porphyria
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abdominal pain, neuropathies, constipation, psychiatric symptoms
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disease in which protoporphyrin accumulates and leads to cutaneous photosensitivity and hepatobiliary disease
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erythropoietic protophyria
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heme synthesis pathway
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glycine + succinyl-CoA (ALA synthase) --> ALA + ALA (ALA dehydratase) --> porphobilinogen x 4 ( porphobilinogen deaminase) --> uroporphyrinogen (uroporphyrinogen decarboxylase)--> protoporporphyrin IX + iron (ferrochelatase) --> heme
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differentiate global genome repair and trancription-coupled repair
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GGR - eliminates lesion from the entire genome
TCR - specifically repair damage on DNA strands of actively transcribed genes |
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what disease is associated with defect in transcription-coupled repair
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Cockayne syndrome
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disease associated with brittle hair and nails with tiger-tail pattern in hair
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trichothiodystrophy
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most common defect in gout
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renal under excretion due to increased urate reabsorption transporter (URAT1)
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3 way in which hyperuricemia can happen
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1. increased URAT1
2. increased PRPP synthetase 3. decreased HGPRT |