[The molecular basis and genetics of diseases associated with disorders of heme biosynthesis]

Haem is a constituent of various haemoproteins which are essential for the function of all living cells. The haem biosynthetic pathway is now well understood and the molecular biology of its function and dysfunction in sideroblastic anemias and porphyrias is currently intensively investigated. Each type of these disorders is the result of a specific reduction in the activity of one of the enzymes of the heme biosynthetic pathway. In this paper a review of the recent progress using molecular probes in the study of sideroblastic anemias and porphyrias is presented. Until now different mutations in genes for haem biosynthesis pathway have been described and other mutations will be identified in the near future and this will provide new tools for the diagnosis of mutated genes carriers. This is particularly important in porphyrias with acute manifestations (acute intermittent porphyria, coproporphyria and variegate porphyria) since the prevention of acute attacks rests on the detection of asymptomatic carriers among members of affected families.