Glutaric acid deficiency

Phenylketonuria (PKU) is an inborn error of metabolism by which the body is unable to convert surplus phenylalanine (PA) to tyrosine for use in the biosynthesis of, for example, thyroxine, adrenaline and noradrenaline. This results from a deficiency in the liver enzyme phenylalanine 4-mono-oxygenase (phenylalanine hydroxylase). A secondary metabolic pathway comes into play in which there is a transamination reaction between PA and a-keto-glutaric acid to produce phenylpyruvic acid (PPVA), a ketone and glutamic acid. Overall, PKU may be defined as a genetic defect in PA metabolism such that there are elevated levels of both PA and PPVA in blood and excessive excretion of PPVA (Fig. 25.7). 

Glutaric acidemia type 1 (GA-1) is an autosomal recessive disorder of lysine, hydroxylysine, and tryptophan metabolism caused by a deficiency of glutaryl-CoA dehydrogenase. It results in the accumulation of 3-hydroxyglutaric and glutaric acid [1],... 

Glularic acid 3-OH-Glutaric acid Glutaconic acid Glutaryl-CoA dehydrogenase deficiency [13]... 

Merinero BC, Perez-Cerda LM, Font MJ, Garcia M, Aparicio G et al (1995) Variable presence of urinary glutaric acid in seven Spanish cases with glutaryl-CoA dehydrogenase deficiency. Neuropediatrics 26 238-242... 

Glutaric acidemia type II is caused by defects in the ETF/ETF-QO proteins. The clinical manifestations of these disorders are similar to medium-chain acyl-CoA dehydrogenase deficiency (discussed later). The double bond formed by the acyl-CoA dehydrogenase has a trans configuration. The double bonds in naturally occurring fatty acids are generally in the cis configuration. The oxidation of unsaturated m-fatty acids requires two auxiliary enzymes, enoyl-CoA isomerase and 2,4-dienoyl-CoA reductase. 

Biotinidase deficiency Folinic acid-responsive seizures Glutaric aciduria type 1 Homocystinuria HyperphenyManinemia due to disorders of biopterin Methylmalonic aciduria Maple syrup urine disease (MSUD) Multiple carboxylase deficiency OAT... 

They are defects in the degradation pathways of leucine, isoleucine, and valine. These conditions are usually diagnosed by examining organic acids in urine with abnormal metabolites also notable on acylcamitine profile. Organic acidemias comprise a variety of disorders and include methylmalonic acidemia (MMA), propionic acidemia (PROP), isovaleric acidemia (IVA), glutaric acidemia type 1 (GA-1), 3-methylcrotonyl carboxylase deficiency (3-MCC), 3-methylglutaconic acidemia (3-MGA), and vitamin B12 uptake, transport, and synthesis defects. 

Table 14.1 Urinary organic acids in patients with neonatal multiple acyl-CoA dehydrogenase deficiences ( glutaric aciduria type IF).

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