Organic acidurias due to disorders in other metabolic pathways

Abstract

The previous chapters of Part III have dealt with the majority of known disorders of organic acid metabolism and with the nature and origins of the abnormal organic aciduria with which they are associated. There are a number of other important disorders, for example pyroglutamic aciduria and d-glyceric aciduria, that do not conveniently fit into the classification of the other diseases, and this chapter provides a suitable place in which to summarize their presentation and characteristics. Other disorders, for example of aromatic amino and organic acid metabolism, are reviewed in great detail elsewhere and fall to some extent outside the scope of this book, except with respect to their abnormal organic acidurias and their study using gas chromatography and mass spectrometry, which are included within the present chapter. Other disorders have not been covered in any detail, either because of their extreme rarity and lack of clarity on their origins, for example 2-hydroxy-n-butyric aciduria associated with methionine malabsorption syndrome [‘oasthouse disease’ (Smith and Strang, 1958)] and with the 2-year-old patient described by Hooft et al. (1965), who was mentally subnormal with white hair and blue eyes, and who excreted between 70 mg of 2-hydroxybutyrate (24 h)⁻¹ and undetectable levels and who responded clinically and biochemically to a low-methionine diet. Other disorders, for example d-2-hydroxyglutaric aciduria, a possible disorder of 5-aminolaevulinate metabolism (Chalmers et al., 1980a), and d-lactic aciduria (Duran et al., 1977; McKusick 24 545), which may be associated with bacterial metabolism in the small bowel (Oh et al., 1979) have not been given detailed consideration for similar reasons.