|
||||||||||||||||||||||||||
|
|
||||||||||||||||||||||||||
| Abbreviations | Nomenclature |
| 1. ALA-Syn | gamma-Aminolevulinate synthase (synthetase) |
| 2. ALA-D | gamma-Aminolevulinate dehydrase (dehydratase); porphobilinogen synthase |
| 3. UROgenI-Syn | Uroporphyrinogen I synthase (synthetase); porphobilinogen deaminase |
| 4. UROgenIII-Cosyn | Uroporphyrinogen III cosynthase (cosynthetase) |
| 5. URO-gen-D | Uroporphyrinogen decarboxylase |
| 6. COPROgenIII-Ox | Coproporphyringen III oxidase |
| 7. PROTOgen-Ox | Protoporphyrinogen oxidase |
| FER-Ch | Ferrochelatase; heme synthase (synthetase) |
7. What happens
with extra porphyrins?
They get accumulated in...
-
the body tissues
- teeth, skin, bones
- urine, feces
- viscera, blood
-
body organs
- liver, spleen
- kidney
- bone marrow
8. Diagnostic features
- Teeth of an orange-brown color, bright pinkish red fluorescence
- Anemic cats
- Depressed, listless
- Hair coat somewhat roughened and dull
- Photosensitization: periodical episodes of nasal and ocular discharges during the summer months, photodermatitis
- Uremia
- Hepatomegaly
- Splenomegaly
- Macrocytic hypocromic anemia
9. Vampire Teeth
Normal
teeth Porphyric
cat teeth
10. Port-wine urine
Portwine Porphyric Normal
Urine
11. Photosensitization
12. Another nice example of photosensitization…
but in cow. It can happen in a severely affected cat...
13. Differential diagnoses
- Feline solar dermatitis
- Lead toxicity
- Anemia
14. Therapy
- Reducing agents
- Acetyl cysteine
- Ascorbic acid
- Spleenectomy (reduce hemolysis and the stimulation of excessive porphyrin production)?\
- Transfusions (inhibit erytropoiesis and decrease porphyrin production)?
- Haematin
15. List of relatively safe (S) and unsafe (U) drugs for porphyric cats
|
Safe Drugs
|
Unsafe Drugs
|
||
| Penicillin Chloramphenicol Halothane Isoflurane Tylosin Corticosteroids Tetracycline Diazepam Morphine Narcotic analgesics |
Neomycin Amphotericin B Gentamicin Tetracycline Ketamine Cardiac glycosides Paracetamol Griseofulvin Phenylbutazone Spironolactone |
Vanomycin Plymycin B Bacitracin Sulfasoxizole Digoxin Methoxyflurane Furosemide Metoclopramide Phenytoin Sulfonamide |
Barbiturates Chlorambucil Chlorpropamide Cyclophosphamide Danazol Estrogens & progestogens Pentazocine Primidone Valproic acid |
16. Genetics of feline porphyria
Porphyria was detected in many breeds:
- Domestic short hair
- all white cats
- unrelated Siamese lines
The degree of expressivity as indicated by the degree of pigmentation of the teeth and skeletal tissues varies considerably among individuals:
- photodermatitis
- renal involvement
- anemia
- Inheritance indicates Autosomal Dominant with complete penetration
- In homozygous status - lethal?
- Spontaneous new mutations - MIMIC GENES
- Possibility of multiply genes?
- It's not a disease of larger population
- Affects male and female cats
- More severe in females?
- Disease of the older cats?
17. Genetic counselling
- Do not breed affected animals
- If affected heterozygous cat is bred to normal cat, the chance to get affected kittens is 50:50
- If affected homozygous cat is bred to normal cat - all kittens will be affected
18. Management
- High carbohydrate diet (decreases porphyrin excretion?)
- Don't give any medications unless needed
- Keep a cat away from the sun, no sunbathes
- Affected cats rarely survive beyond their middle age?
19. Significance of feline porphyria
- This is a rare and very serious disease
- Cats don't like it!
- Porphyric cats are used as animal models for researches on human porphyrias