Diagnosis Of Methylmalonic Acidemia Research Articles

Validity and reliability of the MetabQoL 1.0 and assessment of neuropsychiatric burden in organic acidemias: Reflections from Turkey

ObjectivesThe MetabQoL 1.0 is the first disease-specific health related quality of life (HrQoL) questionnaire for patients with intoxication-type inherited metabolic disorders. Our aim was to assess the validity and reliability of the MetabQoL 1.0, and to investigate neuropsychiatric burden in our patient population. MethodsData from 29 patients followed at a single center, aged between 8 and 18 years with the diagnosis of methylmalonic acidemia (MMA), propionic acidemia (PA) or isovaleric acidemia (IVA), and their parents were included. The Pediatric Quality of Life Inventory (PedsQoL) was used to evaluate the validity and reliability of MetabQoL 1.0. ResultsThe MetabQoL 1.0 was shown to be valid and reliable (Cronbach's alpha: 0.64–0.9). Fourteen out of the 22 patients (63.6%) formally evaluated had neurological findings. Of note, 17 out of 20 patients (85%) had a psychiatric disorder when evaluated formally by a child and adolescent psychiatrist. The median mental scores of the MetabQoL 1.0 proxy report were significantly higher than those of the self report (p = 0.023). Patients with neonatal-onset disease had higher MetabQoL 1.0 proxy physical (p = 0.008), mental (p = 0.042), total scores (p = 0.022); and self report social (p = 0.007) and total scores (p = 0.043) than those with later onset disease. ConclusionsThis study continues to prove that the MetabQoL 1.0 is an effective tool to measure what matters in intoxication-type inherited metabolic disorders. Our results highlight the importance of clinical assessment complemented by patient reported outcomes which further expands the evaluation toolbox of inherited metabolic diseases.

Methylmalonic acidemia (MMA) with homocystinuria cblD & cblF types - A rare disorder of vitamin Bmetabolism in the western region of India

Methylmalonic acidemia (MMA) with homocystinuria cblD & cblF type, a very rare disorder of vitamin B12 metabolism, can result in severe neurological complications in a child. The incidence of combined MMA with homocystinuria cblD & cblF type is estimated as less than 1: 100,000. Mutation analysis by next-generation sequencing (NGS) and validation of the NGS variant by Sanger sequencing, is not only the gold standard in diagnosis of MMA but also, can help in the choice of treatment strategy as B12 responsive or unresponsive. We report a male child initially presented at 10 months of age with poor feeding, delayed growth and no head control (milestone, normally present at 3-4 months). The child on evaluation was diagnosed as a case of MMA with homocystinuria type cblD & cblF, based on investigations such as liquid chromatography-mass spectrometry (LC-MS) and mutation analysis done by next-generation sequencing (NGS) validation with Sanger sequencing. He was treated with vitamin B12 supplements and other supportive conservative therapy. Subsequently, he developed global developmental delay and severe neurological complications, within two years. The child was admitted to the pediatric ICU and he underwent percutaneous endoscopic gastrostomy (PEG) and placed on mechanical ventilation via tracheostomy in situ. Unfortunately, the child did not respond to treatment and succumbed to death, despite all resuscitative measures. The aim of this case report is to create awareness about a clinical presentation associated with a very rare metabolic disorder, MMA with homocystinuria cblD & cblF types and the need for early diagnosis, also, to establish an outline for the treatment in these patients.

Methylmalonic acidemia: Neurodevelopment and neuroimaging.

Methylmalonic acidemia (MMA) is a genetic disease of abnormal organic acid metabolism, which is one of the important factors affecting the survival rate and quality of life of newborns or infants. Early detection and diagnosis are particularly important. The diagnosis of MMA mainly depends on clinical symptoms, newborn screening, biochemical detection, gene sequencing and neuroimaging diagnosis. The accumulation of methylmalonic acid and other metabolites in the body of patients causes brain tissue damage, which can manifest as various degrees of intellectual disability and severe neurological dysfunction. Neuroimaging examination has important clinical significance in the diagnosis and prognosis of MMA. This review mainly reviews the etiology, pathogenesis, and nervous system development, especially the neuroimaging features of MMA.

Prenatal diagnosis of methylmalonic acidemia by amniotic fluid metabolites analysis using mass spectrometry

Objective To investigate the effect of tandem mass spectrometry and gas chromatography–mass spectrometry to make prenatal diagnosis of methylmalonic acidemia (MMA) by detecting organic acid and acylcarnitine in amniotic fluid. Methods From October 11, 2007 to December 20, 2014, 131 pregnant women with MMA proband received prenatal diagnosis of MMA in Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine (case group). Another 120 cases of pregnant women for conventional prenatal diagnosis at the same period were as control group. The pregnant women of two groups had the amniocentesis at 16 to 20 weeks of gestation. The levels of propionylcarnitine(C3) and acetylcarnitine(C2) in amniotic fluid were detected by tandem mass spectrometry. The methylmalonic acid and methylcitrate acid were detected by gas chromatography–mass spectrometry. MMA gene of cells in amniotic fluid of eighty fetuses with proband clearly diagnosed were detected by gene testing. Data were analyzed by Wilcoxon test. Results In case group, 29 fetuses were found positive for higher level of C3, C3/C2, methylmalonic acid and methylcitrate acid compared with normal reference value, and the detected rate of fetal MMA was 22.1%(29/131). The levels of C3 and C3 / C2 in amniotic fluid of these 29 cases were higher than those in control group[8.13(2.42–16.70) vs 1.04(0.52–3.40) µmol/L, Z =–8.313; 0.77(0.30–1.79) vs 0.10(0.05–0.22), Z=–8.374; P 0.05); while they were lower than those of positive MMA fetuses (all P<0.05). Among 29 positive fetuses, 16 fetuses were detected MMA gene, five were diagnosed as MUT forms of MMA and 11 were MMACHC forms of MMA. In 102 MMA negative fetuses, 64 fetuses were detected MMA gene, 44 were found one mutant site and 20 were found no gene mutation. The coincidence rate between gene detecting and mass spectrometry was 100%(80/80). Conclusions Mass spectrometry could be used to measure the C3, methylmalonic acid and methylcitrate acid levels in amniotic fluid of pregnant women with MMA proband to make prenatal diagnosis. Key words: Amino acid metabolism, inborn errors; Prenatal diagnosis; Amniotic fluid; Tandem mass spectrometry; Gas chromatography–mass spectrometry

Application of gene capture technology combined with next generation sequencing technology on methylmalo-nic acidemia

Objective To assess the efficiency and reliability of clinical genetic diagnosis of methylmalonic acidemia(MMA) using new generation sequencing platform(HiSeq2000). Methods 1.Nine patients diagnosed with clinical signs of MMA were recruited.DNA library from the patients were mixed with designed gene capture probe.The whole exons region of 48 genes related to organic acid metabolism were screened using the gene capture combined with high-throughput sequencing.2.The joints were removed and the low quality data were filtered, the data were analyzed by means of SNP and InDel.To avoid the false positive, the abnormal sites were verified using the Sanger sequencing method.3.The detection of the organic acid in the urine was performed through gas chromatography-mass spectrometry and other auxiliary examinations. Results 1.Gene mutation: 7 gene mutations of MMACHC were identified in 7 patients.Seven mutations: c.482G>A, c.567_568insT, c.609G>A, c.440_441del, c.80A>G, c.315C>G, c.90G>A were screened.The mutation c. 440_441del had not been reported before, and others were all related to the disease.Two gene mutations of mutase apoenzyme(MUT) were identified in 1 case, all of which were introns: .c.754-1G>C, c.1677-1G>A.The novel mutation was c. 754-1G>C.No gene mutation was identified in 1 patient.2.Clinical manifestation: all of the patients were development delay, but the degrees were different; 3 patients with convulsion; 1 patient with headache and central facial paralysis; 1 patient with repeated intractable metabolic acidosis; 1 patient with repeated hemolysis.Electroencephalogram of the all patients were abnormal; the result of cranial MRI of the 8 patients were abnormal; In all patients, urine level of methylmalonic acid significantly increased(273.4-146 022.8 times). Blood homocysteine of 8 patients were significantly increased(27.13-396.84 μmol/L, normal<20 μmol/L).3.Sanger sequencing: there were no false positive exists. Conclusions 1.There were not a correlation between the clinical manifestation and gene mutation of the patients with MMA.The c. 609G>A was the hotspot mutation of MMACHC gene in Chinese patients with MMA and homocysteinemia.2.The mutations c. 440_441del and c. 754-1G>C were presumed to be novel mutations.3.Gene capture technology combined with next-generation sequencing technology could be used to interrogate the wealth of data available in the human genome and lay the foundations for counseling of gene.This platform can be readily and timely adopted by clinical molecular diagnosis of MMA and represents a high throughput, high sensitivity, high efficiency and other characteristics approach for screening common genetic diseases. Key words: Gene capture technology; Next-generation sequencing technology; Methylmalonic acidemia; Homocysteinemia; Development delay; Gene mutation

Coma Caused by Methylmalonic Acidemia in a Taiwanese Girl

Methylmalonic acidemia (MMA) is an inborn error of metabolism caused by an accumulation of methylmalonic acid in blood and body tissue due to severe defi ciency or a lack activity of the mitochondrial methylmelonyl-CoA mutase (MCM) enzyme. Affected individuals are typically presented during the newborn period with vomiting, failure to thrive, hyperammoninemia and ketoacidosis. Several mutations on MCM gene (MUT gene) were reported worldwide, but Taiwan. Here, we described a previously healthy 2-year-old Taiwanese girl, who had normal growth and developmental milestones, presented with abdominal pain, vomiting and was in coma. Physical examination revealed tachycardia, tachypnea and poor skin tugor. Laboratory investigations showed high anion gap (anion gap 35 mmol/L) metabolic acidosis (HCO3 - 2.7 mmol/ L), normal plasma osmolar gap (10 mosm/kgH2O), β-hydroxybutyrate (4 mmol/l), ketonuria, hypoglycemia (2.6 mmol/l), hyperammoneemia (152.9 μmol/l), normal lactic acid level, normal renal function, suggesting a clinical diagnosis of organic acidemia. Urinary analysis for organic acid showed increased excretion of methylmalonic acid and in vitro MCM enzyme activity analysis by detecting the lymphoblast revealed trivial residual activity. Molecular analysis of MCM gene revealed that she was compound heterozygous for two mutation of MUT gene, a recurrent G427D and a novel mutation F307L; these two mutations are not identified of 100 alleles for 50 unrelated normal Taiwanese. MMA should be considered as a cause of high anion gap metabolic acidosis in children, even without previous episode and normal development milestone. Molecular study is needed to make a diagnosis of MMA under the trivial residual activity of MCM enzyme.

Diagnosis of Methylmalonic Acidemia from Dried Blood Spots by HPLC and Intramolecular-Excimer Fluorescence Derivatization

Methylmalonic acidemias, a group of heterogeneous disorders, are characterized by accumulation of methylmalonic acid (MMA) and its byproducts in biological fluids (1)(2). Methylmalonic acidemia is now included in all tandem mass spectrometry (MS/MS)-based newborn screening programs (3)(4)(5). Detection is based on the finding of increased propionylcarnitine and/or increased propionylcarnitine-to-acetylcarnitine ratio in dried blood spots (DBS) by MS/MS. These markers, however, are not specific because they are increased in propionic acidemia and, possibly, in multiple carboxylase deficiency (3). In most programs, newborns or patients with initial positive results are recalled for a second blood spot, and a urine sample is collected for organic acid analysis to differentiate among the three disorders. In the present study, we used the intramolecular-excimer fluorescence derivatization approach of Nohta and coworkers (6)(7) to form a fluorescent derivative of MMA. This would allow the detection of MMA in DBS samples from affected neonates, leading to a conclusive diagnosis with the remains of the DBS within a short time, often the same working day. From a DBS, four 3.2-mm discs were punched and extracted into 250 μL of methanol containing 20 μmol/L malonic acid (MA) as internal calibrator by vortex-mixing for 30 s and standing at room temperature for 1 h. After evaporation and reconstitution of the residue …

Early amniocentesis and amniotic fluid organic acid levels in the prenatal diagnosis of organic acidemias

Organic acids were studied in amniotic fluids taken by early amniocentesis between 6 to 12 weeks in control pregnancies. The prenatal diagnosis of methylmalonic acidemia and propionic acidemia could be made by the measurement of methylmalonic and methylcitric acid respectively in the amniotic fluid taken simultaneously with chorionic villi at the 11th week of gestation.

Methylmalonic acidemia with the unusual complication of severe hyperglycemia.

We describe a case of neonatal methylmalonic acidemia with the unusual complication of severe, insulin-resistant hyperglycemia. Methylmalonic acidemia, an inherited metabolic disease affecting the catabolism of propionic acid, is manifested by persistent metabolic acidosis, urinary excretion of large amounts of methylmalonic acid, and occasionally by hypoglycemia. Severe and persistent metabolic acidosis and hyperglycemia, despite large doses of insulin, were observed in this infant, who excreted large amounts of methylmalonic acid. The diagnosis of methylmalonic acidemia was confirmed by gas chromatography-mass spectroscopy, but the patient died before the defect in glucose tolerance could be delineated. We hypothesize that, in addition to the methylmalonic acidemia, the patient may have had an insulin-receptor defect, which was manifested as an inappropriate response to endogenous and exogenous insulin.