Porphyrias Inherited disorders Causes Classifications Diagnosis and Treatment

Porphyrias

The porphyrias are inherited disorders.

porphyrias are metabolic disorders caused by altered activities of enzymes within the heme biosynthetic pathway

Each involves a specific enzyme of heme bio­synthesis.

Porphyrias are classified as :

  • · Hepatic – (neuropathic features)
  • · Erythropoietic – (skin involvement).

The hepatic porphyrias present with neurologic features:

  • · Neuropathic abdominal pain
  • · Neuropat~y
  • · Mental disturbances.

The erythropoie.tic porphyrias present with:

  • · Cutaneous sehsitivity
  • · Scarring and pigmentation of skin.

Porphyrias Classification of the human porphyrias

  • as hepatic or erythropoietic and as acute or cutaneous, the affected enzymes, patterns of inheritance and their major biochemical features
Disease Classification Enzyme affected* Inheritance Major biochemical findings
Tissue site ClinicalCestodes Tape Worms Taenia Saginata & Solium cysticercii neurocysticercosis Diagnosis Treatment. Read more ... » features Urine Plasma Erythrocytes Feces
-minolevulinic acid dehydratase porphyria (ADP) Hepatic Acute ALAD Autosomal recessive ALA, copro-porphyrin III ALA, copro-porphyrin III Zinc proto-porphyrin & low ALAD activity
Acute intermittent porphyria (AIP) Hepatic Acute PBGD Autosomal dominant ALA, PBG, copro-porphyrin Low PBGD activity
Hereditary coproporphyria (HCP) Hepatic Acute & cutaneous CPO Autosomal dominant ALA, PBG, copro-porphyrin III Copro-porphyrin III
Variegate porphyria (VP) Hepatic Acute & cutaneous PPO Autosomal dominant ALA, PBG, copro-porphyrin III Fluorescence peak at 626 nm Copro-porphyrin III & protoporphyrin
Porphyria cutanea tarda (PCT) Hepatic Cutaneous UROD Autosomal dominant Uroporphyrin & hepta-carboxyl-porpyrin Uroporphyrin & hepta-carboxyl-porpyrin Isocopro-porphyrin
Hepato-erythropoietic porphyria (HEP) Hepatic Cutaneous UROD Autosomal recessive Uroporphyrin & hepta-carboxyl-porpyrin Uroporphyrin & hepta-carboxyl-porpyrin Zinc proto-porphyrin & low UROD activity Isocopro-porphyrin
Congenital erythropoietic porphyria (CEP) Erythro-poietic Cutaneous UROS Autosomal recessive Uroporphyrin I & copro-porphyrin I Uroporphyrin I & copro-porphyrin I Uroporphyrin I & copro-porphyrin I Copro-porphyrin I
Erythropoietic protoporphyria (EPP) – classic form Erythro-poietic Cutaneous FECH Autosomal dominant Protoporphyrin Free protoporphyrin Protoporphyrin
EPP – variant form Erythro-poietic Cutaneous ALAS2 X-linked recessive Protoporphyrin Free & zinc protoporphyrin Protoporphyrin

 

Causes of porphyrias :


  • · Environmental
  • · Physiological
  • · Genetic.
  • The porphyrias are diagnosed and classified by chrmatography and demonstration of specific enzyme deficiency or gene defec
Risk Factors

HEPATIC PORPHYRIAS

  • There is rapid onset of neurologic manifestations. There is elevated levels of plasma and urinary ALA (Urinary gamma amino levulinic acid and PBG-Por­phobilinogen).

ALA-dehydratase deficient porphyria

Acute intermittent porphyria

Treatment: Narcotic analgesics, IV glucoseSome Facts about Glucocorticoid & Major side effects. Read more ... », phe­nothiazines

Porphyria cutanea tarda There is :

  • Cutaneous photosensitivity
  • Vesicles and bullae on exposed skin Hyperpigmentation
  • It is precipitated by alcohol, iron, estrogens Treatment: Repeated phlebotomy (450 ml of blood is removed by cutting a vein), chloroquine, hydrochloroquine(HCQ) .

Hereditary corpoporphyria

 

  • Common in women
  • There is photosensitivity of skin

Treatment:

  • phlebotomy and chloroquine

Variegate porphyria

  • Presents with neurological symptoms and photosen­sitivity
  • ERYTHROPOIETIC PORPHYRIAS X-linked sideoblastic anaemia
  • There is refractory anaemia, hypersplenism, hemosi­derosis

Treatment: is pyridoXine supplementation

Congenital porphyria

Treatment:

  •  is splenectomy, protection from sun­light, beta carotene, bone marrow transplant, stem cell therapy

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