scholarly journals Proteinuria as a presenting sign of combined methylmalonic acidemia and homocysteinemia: case report

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Ru-Yue Chen ◽  
Xiao-Zhong Li ◽  
Qiang Lin ◽  
Yun Zhu ◽  
Yun-Yan Shen ◽  
...  
Keyword(s):  
Organic Acids ◽  
Vitamin B12 ◽  
Metabolic Diseases ◽  
Methylmalonic Acid ◽  
Clinical Manifestations ◽  
Methylmalonic Aciduria ◽  
Methylmalonic Acidemia ◽  
Initial Presentation ◽  
Gas Chromatography Mass Spectrometry ◽  
Persistent Proteinuria

Abstract Background Disorders of the metabolism and absorption of vitamin B12 can lead to decrease in activity of methionine synthetase and methylmalonate coenzyme A mutase (MMUT), which results in increased levels of methylmalonic acid and homocysteine in blood and urine. Often, combined methylmalonic acidemia (MMA) and homocysteinemia is misdiagnosed due to a lack of specific symptoms. The clinical manifestations are diverse, but proteinuria as the initial presentation is rare. Case presentation Two cases of MMA with homocysteinemia in children are reported. Proteinuria were a primary presenting symptom, followed by anemia and neurologic symptoms (frequent convulsions and unstable walking, respectively). Screening of amino acids and acyl carnitine in serum showed that the propionyl carnitine:acetylcarnitine ratio increased. Profiling of urinary organic acids by gas chromatography–mass spectrometry revealed high levels of methylmalonic acid. Homocysteine content in blood was increased. Comprehensive genetic analyses of peripheral blood-derived DNA demonstrated heterozygous variants of methylmalonic aciduria type C and homocystinuria (MMACHC) and amnionless (AMN) genes in our two patients, respectively. After active treatment, the clinical manifestations in Case 1 were relieved and urinary protein ceased to be observed; Case 2 had persistent proteinuria and was lost to follow-up. Conclusions Analyses of the organic acids in blood and urine suggested MMA combined with homocysteinemia. In such diseases, reports of renal damage are uncommon and proteinuria as the initial presentation is rare. Molecular analysis indicated two different genetic causes. Although the pathologic mechanisms were related to vitamin B12, the severity and prognosis of renal lesions were different. Therefore, gene detection provides new insights into inherited metabolic diseases.

Acrodermatitis-Like Syndrome in Organic Aciduria

PEDIATRICS ◽  
1994 ◽  
Vol 93 (3) ◽  
pp. 537-537
Author(s):  
U. Blecker ◽  
Y. Vandenplas ◽  
L. De Meirleir ◽  
L. De Raeve ◽  
J. Ramet
Keyword(s):  
Vitamin B12 ◽  
Autosomal Recessive ◽  
Clinical Manifestations ◽  
Methylmalonic Aciduria ◽  
Organic Aciduria ◽  
Asymptomatic Patients ◽  
High Doses

Methylmalonic aciduria (MMA) is an autosomal recessive in-born error of metabolism with a variation in the severity of the clinical manifestations, ranging from asymptomatic patients to fulminating neonatal forms causing severe ketosis, acidosis, hyperammonemia, pancytopenia, coma, and death. Severe cases can be treated with high doses of vitamin B12 and a diet low in proteins. We describe an exceptional manifestation of MMA. A 14-month-old boy with a neonatal manifestation of MMA was admitted during an intercurrent infection with ketoacidosis and hypoglycemia.

scholarly journals The vitamin B12 processing enzyme, mmachc, is essential for zebrafish survival, growth and retinal morphology

2020 ◽  
Vol 29 (13) ◽  
pp. 2109-2123 ◽  
Author(s):  
Jennifer L Sloan ◽  
Nathan P Achilly ◽  
Madeline L Arnold ◽  
Jerrel L Catlett ◽  
Trevor Blake ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Cholesterol Metabolism ◽  
Wide Spectrum ◽  
Clinical Manifestations ◽  
Methylmalonic Acidemia ◽  
Fluorescent Reporters ◽  
Early Embryonic Lethality ◽  
Full Complement ◽  
Human Disorder ◽  
Cobalamin Metabolism

Abstract Cobalamin C (cblC) deficiency, the most common inborn error of intracellular cobalamin metabolism, is caused by mutations in MMACHC, a gene responsible for the processing and intracellular trafficking of vitamin B12. This recessive disorder is characterized by a failure to metabolize cobalamin into adenosyl- and methylcobalamin, which results in the biochemical perturbations of methylmalonic acidemia, hyperhomocysteinemia and hypomethioninemia caused by the impaired activity of the downstream enzymes, methylmalonyl-CoA mutase and methionine synthase. Cobalamin C deficiency can be accompanied by a wide spectrum of clinical manifestations, including progressive blindness, and, in mice, manifests with very early embryonic lethality. Because zebrafish harbor a full complement of cobalamin metabolic enzymes, we used genome editing to study the loss of mmachc function and to develop the first viable animal model of cblC deficiency. mmachc mutants survived the embryonic period but perished in early juvenile life. The mutants displayed the metabolic and clinical features of cblC deficiency including methylmalonic acidemia, severe growth retardation and lethality. Morphologic and metabolic parameters improved when the mutants were raised in water supplemented with small molecules used to treat patients, including hydroxocobalamin, methylcobalamin, methionine and betaine. Furthermore, mmachc mutants bred to express rod and/or cone fluorescent reporters, manifested a retinopathy and thin optic nerves (ON). Expression analysis using whole eye mRNA revealed the dysregulation of genes involved in phototransduction and cholesterol metabolism. Zebrafish with mmachc deficiency recapitulate the several of the phenotypic and biochemical features of the human disorder, including ocular pathology, and show a response to established treatments.

scholarly journals Genetic testing is necessary for correct diagnosis and treatment in patients with isolated methylmalonic aciduria: a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Katarína Brennerová ◽  
Martina Škopková ◽  
Mária Ostrožlíková ◽  
Jana Šaligová ◽  
Juraj Staník ◽  
...  
Keyword(s):  
Genetic Testing ◽  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Clinical Symptoms ◽  
Oral Treatment ◽  
Correct Diagnosis ◽  
Methylmalonic Aciduria ◽  
Intensive Treatment ◽  
Genetic Tests

Abstract Background Isolated methylmalonic aciduria can be caused by pathogenic mutations in the gene for methylmalonyl-CoA mutase or in the genes encoding enzymes involved in the intracellular metabolism of cobalamin. Some of these mutations may be cobalamin responsive. The type of methylmalonic aciduria cannot always be assumed from clinical manifestation and the responsiveness to cobalamin has to be assessed for appropriate cobalamin administration, or to avoid unnecessary treatment. The cases presented herein highlight the importance of genetic testing in methylmalonic aciduria cases and the need for standardisation of the in vivo cobalamin-responsiveness assessment. Case presentation We describe two patients who presented in the first week of life with rapid neurological deterioration caused by metabolic acidosis with severe hyperammonaemia requiring extracorporeal elimination in addition to protein restriction, energy support, carnitine, and vitamin B12 treatment. The severity of the clinical symptoms and high methylmalonic acid concentrations in the urine (>30,000 μmol/mmol of creatinine) without hyperhomocysteinaemia in both of our patients suggested isolated methylmalonic aciduria. Based on the neonatal manifestation and the high methylmalonic acid urine levels, we assumed the cobalamin non-responsive form. The in vivo test of responsiveness to cobalamin was performed in both patients. Patient 1 was evaluated as non-responsive; thus, intensive treatment with vitamin B12 was not used. Patient 2 was responsive to cobalamin, but the dose was decreased to 1 mg i.m. every two weeks with daily oral treatment due to non-compliance. Genetic tests revealed bi-allelic mutations in the genes MMAB and MMAA in Patient 1 and 2, respectively. Based on these results, we were able to start intensive treatment with hydroxocobalamin in both patients. After the treatment intensification, there was no acute crisis requiring hospitalisation in Patient 1, and the urine methylmalonic acid levels further decreased in Patient 2. Conclusions Despite carrying out the in vivo test of responsiveness to cobalamin in both patients, only the results of molecular genetic tests led us to the correct diagnosis and enabled intensive treatment with hydroxocobalamin. The combination of the standardized in vivo test of cobalamin responsiveness and genetic testing is needed for accurate diagnosis and appropriate treatment of isolated methylmalonic aciduria.

METHYLMALONIC ACID

PEDIATRICS ◽  
1973 ◽  
Vol 51 (6) ◽  
pp. 1012-1015
Author(s):  
Lewis A. Barness
Keyword(s):  
Vitamin B12 ◽  
Inborn Errors Of Metabolism ◽  
Methylmalonic Acid ◽  
Methylmalonic Aciduria ◽  
Organic Aciduria ◽  
Combined System ◽  
Inborn Errors ◽  
System Disease ◽  
Amino Aciduria

Methylmalonate studies have led to some understanding of vitamin B12 metabolism as well as certain inborn errors of metabolism. These, in turn, have served as models of a group of diseases related to acidosis, so that the study of organic aciduria at present is similar to that of amino aciduria 20 years ago. Techniques for studying these have been developed. Many unanswered questions remain. (1) What does methylmalonate do? Does it, itself, cause the acidosis? Does it cause a deficiency of succinate in the oxidative cycle? (2) Are more direct ways of increasing succinate available? (3) What is the relation of methylmalonate to combined system disease or vitamin B12 neuropathy? (4) Are enzymes defective or absent? (5) What is the significance of methylmalonate in the newborn? (6) How does one counsel or treat families which include members with methylmalonic aciduria?

Comparison of two methods for measuring methylmalonic acid as a marker for vitamin B12 deficiency

Diagnosis ◽  
2015 ◽  
Vol 2 (1) ◽  
pp. 67-72 ◽  
Author(s):  
Rima Obeid ◽  
Jürgen Geisel ◽  
Wolfgang Herrmann
Keyword(s):  
Mass Spectrometry ◽  
Vitamin B12 ◽  
Methylmalonic Acid ◽  
Vitamin B12 Deficiency ◽  
Gas Chromatography Mass Spectrometry ◽  
Excellent Correlation ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
B12 Deficiency ◽  
Mass Spectrometry Assay

AbstractMethylmalonic acid (MMA) is a functional marker of vitamin B12 status and a valuable diagnostic tool. The gas chromatography mass spectrometry (GCMS) MMA assay has been used for decades in clinical studies.In this study, we compared a newly developed liquid chromatography tandem mass spectrometry assay for MMA (ClinMassThe GCMS and LC-MS/MS assays showed a strong correlation (r=0.92, p<0.001) particularly at low holoTC levels (deficiency is more probable). Forty six cases had MMA>300 nmol/L with both methods. Only five subjects showed MMA GCMS>300 nmol/L, but MMA LC-MS/MS≤300 nmol/L. However, the LC-MS/MS method showed a slightly better correlation with other B12 markers (holoTC, total B12). In addition, the LC-MS/MS method offers several advantages over the GCMS method, such as saving time and costs, precision, flexibility and popularity in modern labs.The new LC-MS/MS assay for MMA showed an excellent correlation to the GCMS method. The two methods showed similar agreements with other vitamin B12 markers.

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