On the pathogenesis of favism.

In some Mediterranean areas-mainly the Balearic Islands, Sardinia, Sicily, Greece, Cyprus, and Israel-where the cultivation and consumption of broad beans (Vicia faba) are extensive, favism is rather common especially in children. It occurs after the inhalation of some, as yet unidentified constituent(s) of the plant and/or more often after eating the beans, especially when they are fresh. The clinical and epidemiological behaviour of favism presents several apparent inconsistencies with what is known of its pathogenesis. In fact, while some patients present with only mild complaints, such as a mild headache, uneasiness, and weakness or also nausea, vomiting, and dizziness, others are severely ill, the prominent features being sudden severe anaemia, subicterus, and haemoglobinuria (or urobilinuria). Both these clinical states and all the possible intermediate forms may be unique or may occur more than once without any rule in the same individual. Furthermore, it is well known, though often forgotten, that there are many subjects, who tolerate Vicia faba well for their whole lives even though they have G6PD deficiency which is always associated with haemolytic anaemia induced by Vicia faba or by a series of drugs. For instance a series of 50 subjects with severe favism was tested in north Sardinia. Among the male relatives of the propositi there were 61 fathers and brothers (aged over 10) who were all severely enzyme deficient. Of these only 15 were found to have had severe favism at one time though they all ate broad beans regularly, and even though 2 of the fathers without favism had previously had severe quinine haemoglobinuria. Mild or 'minor' favism has been studied rarely and almost all the published reports deal with the severe form, also called 'haemoglobinuric' or 'haemolytic' favism. I believe that favism should not be identified a priori with drug-induced haemolysis nor should it be studied only in its severe form. Therefore, I would like to present the results of