From June 1998 to May 2007, 9566 urine samples were collected from patients with psychomotor deficits, seizures, vomiting and unconsciousness in Peking University First Hospital. Their urine organic acids profiles were analysed using gas chromatography - mass spectrometry (GCMS), GCMS solution and Inborn Errors of Metabolism Screening System software. In all patients, blood acylcarnitines were analysed using tandem mass spectrometry. One hundred and sixty-eight patients (1.76%) with organic acidurias were detected. Among them, 116 (116/ 168, 69.0%) had methylmalonic aciduria, 63 (54.3%) of these 116 patients had methylmalonic aciduria combined with homocysteinemia. Sixteen (9.5%) of those patients detected with organic acidurias had propionic aciduria, and 15 (8.9%) had multiple carboxylase deficiency. Seven (4.2%) had glutaric aciduria type 1. After dietary treatment, medicine and rehabilitation, clinical improvements were observed in more than half of the patients. Twenty-eight of the 168 patients (16.7%) recovered and led a normal life. The method of urine organic acid analysis by gas chromatography - mass spectrometry and blood acylcarnitines analysis by tandem mass spectrometry have been established and applied successfully in China, namely Beijing, Shanghai, Wuhan and Guangzhou. The prognoses of Chinese patients with organic acidurias have also improved significantly.
Child ; Child, Preschool ; China ; Humans ; Infant ; Infant, Newborn ; Metabolic Diseases ; urine ; Methylmalonic Acid ; urine ; Multiple Acyl Coenzyme A Dehydrogenase Deficiency ; urine ; Propionic Acidemia ; urine

To evaluate the implication of methymalonic acid (MMA) in the early diagnosis of neural tube defects (NTD), a quantitative assay for MMA was established by using gas chromatography-mass spectrometry with stable isotope of MMA as an internal standard. Amniotic fluid and maternal urine MMA concentration, maternal serum folate, red blood cell folate and vitamin B12 levels were measured in the middle term of NTD-affected and normal pregnancies. Amniotic fluid and maternal urine MMA concentrations in the middle term of NTD affected pregnancies (1.4 +/- 0.9 micromol/L, and 22.1 +/- 12.6 nmol/micromol creatinine) were significantly higher than that of normal pregnancies (1.0 +/- 0. 4 micromol/L, and 2.5 +/- 1.1 nmol/micromol creatinine). There was no significant difference between normal and NTD pregnancies for serum folate, red blood cell folate and vitamin B12 levels. The results suggested that MMAs in amniotic fluid and maternal urine are sensitive markers for early diagnosis of NTD. Vitamin B12 is an active cofactor involved in the remethylation of homocycteine and its deficiency is an independent risk factor for NTD. MMA is a specific and sensitive marker for intracellular vitamin B12 deficiency. This study suggests that it is necessary to monitor the vitamin B12 deficiency and advocates vitamin B12 supplementation with folate prevention program.
Amniotic Fluid/*chemistry ; Biological Markers/analysis ; Biological Markers/urine ; Folic Acid/blood ; Methylmalonic Acid/analysis ; Methylmalonic Acid/*urine ; Neural Tube Defects/*diagnosis ; Neural Tube Defects/metabolism ; Pregnancy Trimester, Second ; *Prenatal Diagnosis ; Vitamin B 12/blood

Homocysteine ; analogs & derivatives ; blood ; Humans ; Infant ; Infant Nutrition Disorders ; complications ; Male ; Methylmalonic Acid ; urine ; Skin Diseases ; etiology ; Vitamin B 12 ; administration & dosage

To evaluate the implication of methymalonic acid (MMA) in the early diagnosis of neural tube defects (NTD), a quantitative assay for MMA was established by using gas chromatography-mass spectrometry with stable isotope of MMA as an internal standard. Amniotic fluid and maternal urine MMA concentration, maternal serum folate, red blood cell folate and vitamin B12 levels were measured in the middle term of NTD-affected and normal pregnancies. Amniotic fluid and maternal urine MMA concentrations in the middle term of NTD affected pregnancies (1.4 +/- 0.9 micromol/L, and 22.1 +/- 12.6 nmol/micromol creatinine) were significantly higher than that of normal pregnancies (1.0 +/- 0. 4 micromol/L, and 2.5 +/- 1.1 nmol/micromol creatinine). There was no significant difference between normal and NTD pregnancies for serum folate, red blood cell folate and vitamin B12 levels. The results suggested that MMAs in amniotic fluid and maternal urine are sensitive markers for early diagnosis of NTD. Vitamin B12 is an active cofactor involved in the remethylation of homocycteine and its deficiency is an independent risk factor for NTD. MMA is a specific and sensitive marker for intracellular vitamin B12 deficiency. This study suggests that it is necessary to monitor the vitamin B12 deficiency and advocates vitamin B12 supplementation with folate prevention program.
Adult ; Amniotic Fluid ; chemistry ; Biomarkers ; analysis ; urine ; Female ; Folic Acid ; blood ; Humans ; Methylmalonic Acid ; analysis ; urine ; Neural Tube Defects ; diagnosis ; metabolism ; Pregnancy ; Pregnancy Trimester, Second ; Prenatal Diagnosis ; Vitamin B 12 ; blood

Two trials of external quality assessment (EQA) of conventional newborn screening tests for phenylketonuria, galactosaemia, congenital adrenal hyperplasia, maple syrup urine disease, homocystinuria, and congenital hypothyroidism, as well as newborn screening tests were performed using tandem mass spectrometry in 2014. A total of 39 specimens in the form of dried blood spots were distributed to 16 laboratories and the response rate of these laboratories was 100%. Screening tests for phenylketonuria and congenital hypothyroidism did not meet the accepted performance criteria in some laboratories. The mean, standard deviation, coefficient of variation, median, and cut-offs were evaluated for each analyte in the newborn screening tests. Two trials of EQA for the analyses of methylmalonic acid, vanillylmandelic acid, catecholamines, metanephrines, organic acids, and amino acids were also performed. A well-designed EQA program and continuous education would improve the performance of biochemical genetic testing.
Adrenal Hyperplasia, Congenital ; Amino Acids ; Catecholamines ; Congenital Hypothyroidism ; Education ; Homocystinuria ; Humans ; Infant, Newborn ; Korea ; Maple Syrup Urine Disease ; Mass Screening ; Methylmalonic Acid ; Molecular Biology* ; Phenylketonurias ; Tandem Mass Spectrometry ; Vanilmandelic Acid

Two trials of external quality assessment (EQA) of conventional newborn screening tests for phenylketonuria, galactosaemia, congenital adrenal hyperplasia, maple syrup urine disease, homocystinuria, and congenital hypothyroidism, as well as of newborn screening tests using tandem mass spectrometry were performed in 2013. A total of 32 specimens in the form of dried blood spots were distributed to 16 laboratories and the response rate of these laboratories was 100%. Total T4, free T4, 17-hydroxyprogesterone, leucine, isoleucine, galactose, methionine, alanine, C8/C2, C8/C10, and C5-OH did not meet the accepted performance criteria. The mean, standard deviation, coefficient of variation, median, and cut-offs were evaluated for each analyte in the newborn screening tests. Two trials of EQA for the analyses of methylmalonic acid, vanillylmandelic acid, very long fatty acids, organic acids, and amino acids were also performed. A well-designed EQA program and continuous education would improve the performance of biochemical genetic tests.
17-alpha-Hydroxyprogesterone ; Adrenal Hyperplasia, Congenital ; Alanine ; Amino Acids ; Congenital Hypothyroidism ; Education ; Fatty Acids ; Galactose ; Homocystinuria ; Humans ; Infant, Newborn ; Isoleucine ; Korea ; Leucine ; Maple Syrup Urine Disease ; Mass Screening ; Methionine ; Methylmalonic Acid ; Molecular Biology* ; Phenylketonurias ; Tandem Mass Spectrometry ; Vanilmandelic Acid

Two external quality assessment (EQA) trials of conventional newborn screening tests for phenylketonuria, galactosemia, congenital adrenal hyperplasia, maple syrup urine disease, homocystinuria, and congenital hypothyroidism, as well as newborn screening tests using tandem mass spectrometry, were performed in 2015. A total of 44 specimens in the form of dried blood spots were distributed to 16 laboratories and the response rate of these laboratories was 100%. The mean, standard deviation, coefficient of variation, median, and cut-offs were evaluated for each analyte in the newborn screening tests. Two EQA trials for the analyses of methylmalonic acid, vanillylmandelic acid, catecholamines, metanephrines, organic acids, and amino acids were also performed. A well-designed EQA program and continuous education would improve the performance of biochemical genetics tests.
Adrenal Hyperplasia, Congenital ; Amino Acids ; Catecholamines ; Congenital Hypothyroidism ; Education ; Galactosemias ; Homocystinuria ; Humans ; Infant, Newborn ; Korea* ; Maple Syrup Urine Disease ; Mass Screening ; Methylmalonic Acid ; Molecular Biology* ; Phenylketonurias ; Tandem Mass Spectrometry ; Vanilmandelic Acid

OBJECTIVEThe renal impairment in children with methylmalonic aciduria has seldom been reported. To improve knowledge in this aspect, clinical data of five cases with methylmalonic aciduria with renal involvement were analyzed and the results are reported in this paper, which may be of some help in early diagnosis, treatment and in achieving favorable prognosis.

METHODSUrine methylmalonic acid was measured by gas chromatography-mass spectrometry analysis, if the content exceeded the normal range and vitamin B12 deficiency was excluded, the diagnosis of methylmalonic aciduria was confirmed. Homocysteine in plasma was also measured with fluorescence polarization immunoassay to make sure if concomitant homocysteinemia existed. From January 2002 to January 2005, five patients who had renal impairment were diagnosed as methylmalonic aciduria by urinary organic acid analysis. Among them, three were male, two were female, aged from seven months to 26 years, with average of 13 years. Three were presented to pediatric nephrology clinic with hematuria, proteinuria or edema, the other two were presented to pediatric neurology clinic first for psychomotor retardation. Their clinical features, laboratory findings, treatment regimens and prognosis were analyzed and summarized.

RESULTSAll the five patients with methylmalonic aciduria were found to have various degrees of renal impairment, manifested as hematuria or proteinuria. Among them, two cases had gross hematuria and three had microscopic hematuria. Edema was found in two cases and hypertension occurred in one case. Early indicators of renal damage, such as microalbunminuria, N-acetyl-beta-D glucosaminidase, transferrin and alpha-microglobulin showed glomerular and tubular dysfunction. Clinically nephrotic syndrome was diagnosed in one case, the other four cases were diagnosed as glomerulonephritis, and two cases had renal failure. Renal biopsy was performed in one case, tubulo-interstitial damage and mesangial proliferation appeared. Mental retardation and psychomotor disorder were chief nervous system complaints. Leukodystrophy was the main finding on imaging. Megaloblastic anemia was found in three cases. All the five patients were cobalamin-responsive type. Renal impairment was alleviated following treatment, edema and gross hematuria as well as hypertension disappeared later, proteinuria diminished, renal function improved, central nervous system symptoms and hematopoietic function ameliorated.

CONCLUSIONIn patients with hematuria, proteinuria or renal failure of unknown origin, metabolic screening and urinary organic acid analysis should be performed as early as possible to confirm the diagnosis.

Adolescent ; Adult ; Amino Acid Metabolism, Inborn Errors ; complications ; diagnosis ; Child ; Female ; Gas Chromatography-Mass Spectrometry ; Homocystine ; blood ; Humans ; Infant ; Kidney Diseases ; etiology ; Kidney Function Tests ; Male ; Methylmalonic Acid ; urine ; Young Adult

External quality assessment (EQA) trials of conventional newborn screening tests for phenylketonuria, galactosemia, congenital adrenal hyperplasia, maple syrup urine disease, homocystinuria, and congenital hypothyroidism, as well as extended newborn screening tests using tandem mass spectrometry, were performed twice in 2016 and 2017. A total of 44 specimens in the form of dried blood spots were distributed in each trial to 16 laboratories. The response rate of these laboratories was 100%. The mean, standard deviation, coefficient of variation, median, and cut-offs were evaluated for each analyte in the newborn screening tests. EQA trials for the analyses of methylmalonic acid, vanillylmandelic acid, catecholamines, metanephrines, organic acids, and amino acids were also performed. A well-designed EQA program and continuous education would improve the performance of metabolite testing.
Adrenal Hyperplasia, Congenital ; Amino Acids ; Catecholamines ; Congenital Hypothyroidism ; Education ; Galactosemias ; Homocystinuria ; Humans ; Infant, Newborn ; Korea* ; Maple Syrup Urine Disease ; Mass Screening ; Methylmalonic Acid ; Phenylketonurias ; Tandem Mass Spectrometry ; Vanilmandelic Acid

OBJECTIVEWe report the first case of acute encephalopathy induced by vaccination in an infant with methylmalonic aciduria cblA in China.

METHODThe clinical presentation, blood acylcarnitines analysis, urine organic acids analysis and gene studies of the patient were summarized.

RESULTThe proband, a boy, was admitted at the age of 15 months because of recurrent vomiting, acidosis and development delay for 8 months. The previously healthy boy presented vomiting and coma just one hour after hepatitis B vaccination at the age of seven months. Moderate dehydration, electrolyte disturbance and metabolic acidosis had been found. Although his acute metabolic crisis had been corrected soon after intravenous transfusion, psychomotor retardation and recurrent vomiting had been observed. When he was 15 months old, vomiting and lethargy occurred again 3 hours after DTaP vaccination. He was weakened as the illness became worse and got coma with dyspnea 7 days later. He was hospitalized with the suspected diagnosis of viral encephalitis. Blood acylcarnitines analysis, urine organic acids analysis and gene study had been performed for the etiologic investigation.His blood propionylcarnitine (16.3 µmol/L vs. normal range 1.0-5.0 µmol/L) and propionylcarnitine/free carnitine ratio (0.27 vs. normal range 0.03 to 0.25) increased. Markedly elevated urinary methylmalonic acid (388.21 mmol/mol creatinine vs. normal range 0.2 to 3.6 mmol/mol creatinine) and normal plasma total homocysteine supported the diagnosis of isolated methylmalonic aciduria. Two mutations, c.650 T>A (p.L217X) and c.742 C>T (p.Q248X), were identified in his MMAA gene, confirmed the diagnosis of cblA. Each parent carried one of the two mutations. Progressive clinical and biochemical improvement has been observed after hydroxylcobalamin injection, protein-restricted diet with the supplements of special formula and L-carnitine. He is currently 2 years and 7 months old with normal development and general condition.

CONCLUSIONA boy with cblA was firstly detected after the acute encephalopathy induced by vaccination in China. It is important to pay more attention to the patients with metabolic crisis or organ damage after vaccination. Metabolic studies are keys to the diagnosis of potential diseases and improve the outcome.

Amino Acid Metabolism, Inborn Errors ; complications ; Brain Diseases ; chemically induced ; Carnitine ; analogs & derivatives ; Diet, Protein-Restricted ; Hepatitis B Vaccines ; adverse effects ; Humans ; Infant ; Male ; Methylmalonic Acid ; urine ; Mutation ; Vaccination ; adverse effects ; Vitamin B Complex ; Vomiting