Info

Glutaric aciduria type I

c5-dc

Malonic acidemia

c3-dc

Aminoacidopathies

Phenylketonuria Phenylalanine

Maple syrup urine disease Leucine

Homocystinuria Methionine

Argininosuccinate Citrulline synthetase deficiency

Citrin deficiency Citrulline

Argininosuccinate lyase deficiency Citrulline

Ornithine transcarbamylase deficiency Citrulline

Arginase deficiency Arginine

Tyrosinemia type I Tyrosine

Aminoacidopathies

Phenylketonuria Phenylalanine

Maple syrup urine disease Leucine

Homocystinuria Methionine

Argininosuccinate Citrulline synthetase deficiency

Citrin deficiency Citrulline

Argininosuccinate lyase deficiency Citrulline

Ornithine transcarbamylase deficiency Citrulline

Arginase deficiency Arginine

Tyrosinemia type I Tyrosine

AC = acylcarnitine; DC = dioylcarnitine.

palmitoyltransferase I deficiency, and the increased ratio of free carnitine to the sum of C16-acycarnitine and C1g-acylcarnitine (cutoff of 100) is used as a marker for this disease.[9] Although medium-chain acyl-CoA dehydrogenase (MCAD) deficiency is screened using the cutoff of 0.5-1.0 nmol/mL in most laboratories, a retrospective investigation indicated the diagnostic criterion as a Cg-acylcarnitine concentration of more than 0.3 nmol/mL with a Cg-acylcarnitine/C10-acylcarnitine ratio of more than 4.0.[10]

To detect patients with a mild form of propionic acidemia (PA) and methylmalonic aciduria (MMA), a cutoff of 0.25 for the ratio of the intensity of m/z 274 (propionylcarnitine) to that of m/z 260 (acetylcarnitine) seems useful.[11] Transient increases in propionylcarnitine have been frequently observed in infants with ABO incompatibility to the mother.[6] In spite of the application of such a marker, some MMA patients with defects in cobalamine metabolism have been missed.[1]

In PKU screening, a high phenylalanine-to-tyrosine ratio is a specific and sensitive marker to detect PKU using specimens collected in the first 24 hr[12] and to distinguish this disease from liver dysfunction and amino acid infusion.[13] The leucine-to-phenylalanine or methi-onine-to-phenylalanine ratio also may be useful to minimize the false-positive rate in maple syrup urine disease (MSUD) or HCU screening.[6]

Argininosuccinate synthetase (ASS) deficiency, argi-ninosuccinate lyase (ASL) deficiency, and citrin deficiency are detected using high levels of citrulline. The increased argininosuccinic acid concentration, which can be monitored using the designated product ions, is another diagnostic marker for ASL deficiency. Most patients with citrin deficiency have citrulline levels higher than 50 nmol/mL in the neonatal period, together with high values of such amino acids as methionine, phenylalanine, tyrosine, and/or arginine.[11]

Ornithine transcarbamylase deficiency may be screened by the combination of low citrulline and high glutamine levels. Because glutamine is hardly quantified in a routine analysis of MS-MS screening, a second-tier screening method to measure glutamine levels is proposed to reexamine a blood spot with a low citrulline concentration.1-14-1 Similarly, a succinylacetone confirmation test using a blood spot with a high tyrosine level is performed to distinguish tyrosinemia type I from transient neonatal tyrosinemia.[12]

Several organic acidemias share the same diagnostic markers, and urinary organic acid analysis is necessary to distinguish these diseases. Elevated C5-acylcarnitine due to therapy with antibiotics containing pivaryl ester can be distinguished from isovaleric acidemia by urinary organic acid analysis. High levels of hydroxy-C5-acylcarnitines because of a maternal 3-methylcrotonyl-CoA carboxylase

(3MCC) deficiency can be also detected by urinary organic analysis of the newborn and the mother.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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