Mutation Analyses in Selected Exons of the MUT Gene in Indian Patients with Methylmalonic Acidemia.

Deficiency or diminished activity of a cobalamin dependent enzyme methylmalonyl-CoA mutase causes inborn error of metabolism called methylmalonic acidemia (MMA). In this study we elucidated the spectrum of mutations in 21 Indian mut MMA patients by direct sequencing. Sequence analysis identified a total of 70 mutations in exon 2, 9, 11 and 12 of MUT gene. Out of which 26 mutations were predicted to be deleterious and rest were benign. The 23 novel mutations consist of four nonsense mutations (p.N6*, p.G539*, p.E609* and p.I671*), twelve missense mutations (p.K128I, p.N547T, p.D554Y, p.A558T, p.R559P, p.A631T, p.I647T, p.E656D, p.V657E, p.Q660H, p.K679N, and p.G696Y) and seven frame shift mutations (c.375_376insA, c.1642delA, c.1655delC, c.1825_1826insT, c.1957delGA, c.2014delA and c.2062_2063insGA). All of them are point mutations or micro rearrangements. Three of these mutations (p.K621N, p.G648D, p.G630E) have been previously reported; all of them are missense mutations. The mutations are distributed throughout the exon 2, 9, 11 and 12, 38.4 % mutation are located in exon 12.

Liquid-Liquid Extraction and Solid Phase Extraction for Urinary Organic Acids: A Comparative Study from a Resource Constraint Setting.

Pre analytical process of extraction for accurate detection of organic acids is a crucial step in diagnosis of organic acidemias by GCMS analysis. This process is accomplished either by solid phase extraction (SPE) or by liquid-liquid extraction (LLE). Both extraction procedures are used in different metabolic laboratories all over the world. In this study we compared these two extraction procedures in respect of precision, accuracy, percent recovery of metabolites, number of metabolites isolated, time and cost in a resource constraint setup. We observed that the mean recovery from SPE was 84.1 % and by LLE it was 77.4 % (p value <0.05). Moreover, the average number of metabolites isolated by SPE and LLE was 161.8 ± 18.6 and 140.1 ± 20.4 respectively. The processing cost of LLE was economical. In a cost constraint setting using LLE may be the practical option if used for organic acid analysis.

Urinary organic acids quantitated in a healthy north Indian pediatric population.

Human urine gives evidence of the metabolism in the body and contains numerous organic acids and other compounds at a variety of concentration. The concentration of organic acids in urine varies from population to population due to genotype, food habits and other epigenetic and environmental influences. Knowledge of the reference values for urinary organic acids in a healthy pediatric population is very important for critical evaluation. This study was designed to quantify 16 organic acids in a healthy north Indian pediatric population. Early morning urine samples from healthy pediatric subjects of age 1 day to 16 years who did not have symptoms of any disease were analyzed for organic acid content. The children were not on any supplemental vitamins or drugs and were on a free and unrestricted diet. The creatinine concentration of each sample was determined before organic acid analysis. Organic acids were extracted from urine with ethyl acetate, extracted residue was air dried, converted into trimethylsilyl derivatives and analysed by gas chromatography mass spectrometry. Here we reported the age wise mean values and standard deviations for each compound, adjusted for creatinine content (mmol/mol of creatinine). We found the concentration of most of the metabolites are higher in our population in comparison to other populations. Such data may help to provide a basis for diagnosing metabolic abnormalities in patients in a specific ethnicity.

To ascertain the utility of urinary methyl malonic Acid as a potential marker of ischemic heart failure.

BACKGROUND: Methyl Malonic Acid (MMA) is known to be an integral component of the cascade of events in mitochondrial energy metabolism and since heart failure involves energy pathways, it is probable that levels of MMA could be used as a reliable biomarker to objectively identify the disease during the early stages and help in prognostication. MATERIALS AND METHODS: The present study was envisaged to evaluate the relation between urinary MMA levels in patients with Ischemic heart disease and in those progressing to failure. The relationship between the severity of the disease and the level of MMA in urine were also evaluated. Analysis of urinary MMA was done by Gas Chromatography-Mass Spectrometry (GC-MS) using stable isotope dilution. Twenty patients each with Ischemic Heart Disease, heart failure and controls were recruited in this pilot study. RESULTS: The mean value of MMA in patients with IHD was 126.71(±66.3) pmol/L and those with IHF was 390.76 (±97.99) pmol/L with the difference being statistically significant (p<0.001). Co-existing B12 deficiency was excluded as that was a potential confounder. CONCLUSION: Levels of MMA were significantly higher in patients with heart failure compared to those with IHF, which were significantly higher than controls. Evaluation of the correlation between MMA levels and the stage of the disease did not reach statistical significance; but this requires adequately powered studies to support this preliminary finding.