The dicarboxylic acidurias

Abstract

Urine from healthy infants and adults may contain low amounts of aliphatic dicarboxylic acids of chain length C₆–C₈ (Björkman et al., 1976; Lawson et al., 1976) and very low amounts of dicarboxylic acids of similar chain length containing methyl branches (Pettersen and Stokke, 1973; Lawson et al., 1976), cyclopropane rings (Lindstedt et al., 1974) and acetylenic bonds (Lindstedt and Steen, 1975). Increased excretion of C₄–C₁₀ dicarboxylic acids has been reported secondary to a number of pathological conditions, including keto acidosis (Chapter 12), where increased concentrations (up to 0.5 mol per mol of creatinine) of adipic (C_6:0) and suberic (C_8:0) acids occur (Pettersen et al., 1972), and glycogen storage diseases types I and III, where increased but still low concentrations (0.02 mol per mol of creatinine) of odd- and even-numbered saturated acids of chain length C₆ to C₁₀ occur (Dosman et al., 1974). Greatly increased concentrations of dicarboxylic acids have now been observed in the urine of patients with various pathological conditions, generally in the absence of ketosis, and these diseases have been collectively termed here ‘the dicarboxylic acidurias’. A case of neonatal lactic acidosis associated with hypoglycaemia and pronounced dicarboxylic aciduria, particularly of chain length C₁₀–C₁₄ reported by Borg et al. (1972), in whom they postulated a defect in β-oxidation (Lindstedt et al., 1976), was greatly different from the dicarboxylic acidurias described in the sections below.