Proteinuria as a presenting sign of combined methylmalonic acidemia and homocysteinemia: case report
- PDF / 1,760,266 Bytes
- 7 Pages / 595.276 x 790.866 pts Page_size
- 65 Downloads / 216 Views
CASE REPORT
Open Access
Proteinuria as a presenting sign of combined methylmalonic acidemia and homocysteinemia: case report Ru-Yue Chen1, Xiao-Zhong Li1* , Qiang Lin1, Yun Zhu1, Yun-Yan Shen1, Qin-Ying Xu1, Xue-Ming Zhu2, Lin-Qi Chen3, Hai-Ying Wu3 and Xu-Qin Chen4
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. Keywords: Children, Methylmalonic acidemia(MMA), Homocysteinemia, Proteinuria, Vitamin B12
* Correspondence: [email protected] 1 Department of Nephrology and Immunology, Children’s Hospital of Soochow University, Suzhou, Jiangsu, China Full list of author information is available at the end of the article © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's
Data Loading...
