Write about Porphyrias here.
• Group of rare inborn errors of metabolism
• Abnormalities of enzymes involved in the biosynthesis of haem, resulting in the overproduction of the intermediate compounds called 'porphyrins'.
• Extreme heterogeneity
• Chief limiting step in haem production is �-ALA synthetase, with an increase in the is enzyme resulting in an overproduction of porphyrins.
• Haem provides a negative feedback mechanism for the enzyme
• The excess porphyrins are produced in either the liver (Hepatic Porphyria) or in the bone marrow (Erythropoietic Porphyria)
• Two main types - acute and nonacute