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Yang J, Xiu J, Sun Y, Liu F, Shang X, Li G. Three novel mutations of the BCKDHA, BCKDHB and DBT genes in Chinese children with maple syrup urine disease. J Pediatr Endocrinol Metab 2022; 35:303-312. [PMID: 34883003 DOI: 10.1515/jpem-2021-0672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 11/17/2021] [Indexed: 11/15/2022]
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is a rare metabolic autosomal recessive disorder caused by deficiency of the branched-chain α-ketoacid dehydrogenase complex. Mutations in the BCKDHA, BCKDHB and DBT genes are responsible for MSUD. This study presents the clinical and molecular characterizations of four MSUD patients. METHODS Clinical data of patients were retrospectively analyzed, and genetic mutations were identified by whole-exome sequencing. CLUSTALX was employed to analyzed cross-species conservation of the mutant amino acid. The impact of the mutations was analyzed with PolyPhen-2 software. The I-TASSER website and PyMOL software were used to predict the protein three-position structure of the novel mutations carried by the patients. RESULTS Vomiting, irritability, feeding difficulties, seizures, dyspnoea, lethargy and coma were the main clinical presentations of MSUD. Cranial MRI showed abnormal symmetrical signals in accordance with the presentation of inherited metabolic encephalopathy. Seven mutations were detected in four patients, including three novel pathogenic mutations in the BCKDHA (c.656C>A), BCKDHB (deletion of a single-copy of BCKDHB) and DBT (c.1219dup) genes. Structural changes were compatible with the observed phenotypes. CONCLUSIONS Different types of MSUD can display heterogeneous clinical manifestations. Exhaustive molecular studies are necessary for a proper differential diagnosis. The newly identified mutation will play a key role in the prenatal diagnosis of MSUD in the future.
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Affiliation(s)
- Jianmei Yang
- Department of Pediatric Endocrinology, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Jianjun Xiu
- Radiology Department, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Yan Sun
- Department of Pediatric Endocrinology, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Fan Liu
- Department of Pediatric Endocrinology, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Xiaohong Shang
- Department of Pediatric Endocrinology, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Guimei Li
- Department of Pediatric Endocrinology, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, Shandong, China
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Dahpy MA, Saleem TH, El-Asheer OM, ELrasoul AA, Abo Elgeit AM. Clinical, Biochemical, Molecular, and Therapeutic Analysis of Maple Syrup Urine Disease in Upper Egypt. J Pediatr Genet 2020; 10:116-125. [PMID: 33996182 DOI: 10.1055/s-0040-1715111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/22/2020] [Indexed: 10/23/2022]
Abstract
Maple syrup urine disease (MSUD) is an autosomal recessive inherited metabolic disorder caused by mutations in any of the genes encoding for the branched-chain keto dehydrogenase (BCKDH) components. This study screened MSUD patients throughout the whole Upper Egypt describing their symptoms, clinical and laboratory findings, genetic studies, and their treatment, with a 6-month follow-up for their responses. Screening identified three children with MSUD. Homozygous mutation in R195Q single nucleotide polymorphism (SNP) within the BCKDHA gene was found with the second MSUD patient. Follow-up for 6 months to assess the treatment regimens and progression of cases demonstrated that early treatment regimens including a dietary restriction of branched-chain amino acids with L-Carnitine administration could prevent MSUD-associated intellectual disabilities. It was concluded that R195Q SNP is pathogenic, and it may cause inherited forms of MSUD in some patients. MSUD cases have rarely been reported; so these findings will be highly useful for future cases of MSUD in the Upper Egyptian population.
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Affiliation(s)
- Marwa A Dahpy
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Tahia H Saleem
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Osama M El-Asheer
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Ahmed Abd ELrasoul
- Department of Biochemistry, Faculty of Pharmacy, Assiut University, Assiut, Egypt
| | - Amir M Abo Elgeit
- Department of Pediatrics, Faculty of Medicine, Assiut University, Assiut, Egypt
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Han B, Han B, Guo B, Liu Y, Cao Z. Two novel mutations in the BCKDHB gene that cause maple syrup urine disease. Pediatr Neonatol 2018; 59:515-519. [PMID: 29366676 DOI: 10.1016/j.pedneo.2018.01.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Revised: 09/08/2017] [Accepted: 01/02/2018] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND Maple syrup urine disease (MSUD) is a rare metabolic disorder of autosomal recessive inheritance caused by decreased activity of branched-chain α-ketoacid dehydrogenase complex (BCKD). Mutations in the three genes (BCKDHA, BCKDHB and DBT) are associated with MSUD. Here, we describe the presenting symptoms, clinical course and gene mutation analysis of a Chinese boy with MSUD. METHODS Plasma amino acid analysis was performed by tandem mass spectrometry and the levels of organic acids in urine were measured with gas chromatography-mass spectrometry. The BCKDHB gene was sequenced by Sanger method. Furthermore, the significance of the novel mutations was predicted by Polyphen and Mutationtaster. After diagnosis, the patient was fed with protein-restricted diet to reduce intake of BCAA and was treated with l-carnitine. Metabolic parameters, clinical presentation and mental development were followed up. RESULTS The patient was diagnosed as MSUD. Two novel BCKDHB mutations (c.523 T > C and c.478-25_552del100) were identified. In silico analysis predicted that the two mutations were "disease causing". The boy tolerated the treatment well and had symptomatic improvement. He presented with mild hypotonia and had nearly normal DQ scores at the age of 10 months. The two novel mutations resulted in the clinical manifestations of MSUD. Our results may reflect the heterogeneity of the pathogenic variants found in patients with MSUD.
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Affiliation(s)
- Bingjuan Han
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China
| | - Bingchao Han
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China
| | - Bin Guo
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China
| | - Yingxia Liu
- Jinan Maternal and Child Care Hospital, Jinan, 250001, Shandong Province, China; Department of Immunology, Nanjing Medical University, Nanjing, 21166, Jiangsu Province, China.
| | - Zhiyang Cao
- Nanjing Jiangning Hospital, Affiliated to Nanjing Medical University, Nanjing 211100, Jiangsu Province, China.
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Li X, Yang Y, Gao Q, Gao M, Lv Y, Dong R, Liu Y, Zhang K, Gai Z. Clinical characteristics and mutation analysis of five Chinese patients with maple syrup urine disease. Metab Brain Dis 2018; 33:741-751. [PMID: 29307017 DOI: 10.1007/s11011-017-0168-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 12/11/2017] [Indexed: 11/28/2022]
Abstract
Maple syrup urine disease (MSUD) is an autosomal recessive disorder affecting branched-chain amino acids (BCAAs) metabolism and caused by a defect in the thiamine-dependent enzyme branched chain α-ketoacid dehydrogenase (BCKD) with subsequent accumulation of BCAAs and corresponding branched-chain keto acids (BCKAs) metabolites. Presently, at least 4 genes of BCKDHA, BCKDHB, DLD and DBT have been reported to cause MSUD. Furthermore, more than 265 mutations have been identified as the cause across different populations worldwide. Some studies have reported the data of gene mutations in Chinese people with MSUD. In this study, we present clinical characteristics and mutational analyses in five Chinese Han child with MSUD, which had been screened out by tandem mass spectrometry detection of amino acids in blood samples. High-throughput sequencing, Sanger sequence and real-time qualitative PCR were performed to detect and verify the genetic mutations. Six different novel genetic variants were validated in BCKDHB gene and BCKDHA gene, including c.523 T > C, c.659delA, c.550delT, c.863G > A and two gross deletions. Interestingly, 3 cases had identical mutation of BCKDHB gene (c.659delA). We predicted the pathogenicity and analyzed the clinical characteristics. The identification of these mutations in this study further expands the mutation spectrum of MSUD and contributes to prenatal molecular diagnosis of MSUD.
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Affiliation(s)
- Xiaomei Li
- Department of Neonatology, Qilu Children's Hospital of Shandong University, Jinan, Shandong, 250022, China
| | - Yali Yang
- Department of Rehabilitation, Qilu Children's Hospital of Shandong University, Jinan, Shandong, 250022, China
| | - Qing Gao
- Department of Genetics, Jinan Maternity and Child Care Hospital, Jinan, Shandong, 250001, China
| | - Min Gao
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, 23976 Jingshi Road, Jinan, Shandong, 250022, China
| | - Yvqiang Lv
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, 23976 Jingshi Road, Jinan, Shandong, 250022, China
| | - Rui Dong
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, 23976 Jingshi Road, Jinan, Shandong, 250022, China
| | - Yi Liu
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, 23976 Jingshi Road, Jinan, Shandong, 250022, China
| | - Kaihui Zhang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, 23976 Jingshi Road, Jinan, Shandong, 250022, China.
| | - Zhongtao Gai
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, 23976 Jingshi Road, Jinan, Shandong, 250022, China.
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Su L, Lu Z, Li F, Shao Y, Sheng H, Cai Y, Liu L. Two homozygous mutations in the exon 5 of BCKDHB gene that may cause the classic form of maple syrup urine disease. Metab Brain Dis 2017; 32:765-772. [PMID: 28197878 DOI: 10.1007/s11011-017-9959-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 01/24/2017] [Indexed: 01/16/2023]
Abstract
Maple syrup urine disease (MSUD) is a rare autosomal recessive genetic disorder caused by defects in the catabolism of the branched-chain amino acids (BCAAs). Classic form of MSUD (CMSUD) is caused by mutations in BCKDHA, BCKDHB, DBT genes mostly. In this study, we analyzed the clinical and genetic characteristics of two patients with CMSUD. Two homozygous mutations, c.517G > T (p.Asp173Tyr) and c.503G > A (p.Arg168His), both in the exon 5 of BCKDHB were detected respectively. The novel mutation p.Asp173Tyr of patient A, inherited from his parents, is predicted to affect conformation of protein by computer analysis. The reported mutation p.Arg168His observed in patient B seemed to occur in a maternal uniparental disomy inheritance manner. Review of related literature revealed that most missense mutations in exon 5 of BCKDHB in homozygous genotype often result in CMSUD because of its incorrect conformation, and exon 5 of BCKDHB might be a susceptible region. Thus the novel homozygous mutation p.Asp173Tyr and the founder homozygous mutation p.Arg168His may be responsible for the clinical presentation of the two CMSUD patients, facilitating the future genetic counselling and prenatal diagnosis.
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Affiliation(s)
- Ling Su
- Department of Genetics and Endocrinology, Guangzhou women and children's medical center, Guangzhou Medical University, 9 Jinsui Road, Guangzhou, Guangdong province, 510623, China
| | - Zhikun Lu
- Department of Genetics and Endocrinology, Guangzhou women and children's medical center, Guangzhou Medical University, 9 Jinsui Road, Guangzhou, Guangdong province, 510623, China
| | - Fatao Li
- Prenatal Diagnostic Center, Guangzhou women and children's medical center, Guangzhou Medical University, Guangzhou, 510623, China
| | - Yongxian Shao
- Department of Genetics and Endocrinology, Guangzhou women and children's medical center, Guangzhou Medical University, 9 Jinsui Road, Guangzhou, Guangdong province, 510623, China
| | - Huiying Sheng
- Department of Genetics and Endocrinology, Guangzhou women and children's medical center, Guangzhou Medical University, 9 Jinsui Road, Guangzhou, Guangdong province, 510623, China
| | - Yanna Cai
- Department of Genetics and Endocrinology, Guangzhou women and children's medical center, Guangzhou Medical University, 9 Jinsui Road, Guangzhou, Guangdong province, 510623, China
| | - Li Liu
- Department of Genetics and Endocrinology, Guangzhou women and children's medical center, Guangzhou Medical University, 9 Jinsui Road, Guangzhou, Guangdong province, 510623, China.
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Guo Y, Liming L, Jiang L. Two novel compound heterozygous mutations in the BCKDHB gene that cause the intermittent form of maple syrup urine disease. Metab Brain Dis 2015; 30:1395-400. [PMID: 26239723 DOI: 10.1007/s11011-015-9711-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 07/15/2015] [Indexed: 10/23/2022]
Abstract
Intermittent maple syrup urine disease (MSUD) is a potentially life-threatening metabolic disorder caused by a deficiency of branched chain α-ketoacid dehydrogenase (BCKD) complex. In contrast to classic MSUD, children with the intermittent form usually have an atypical clinical manifestation. Here, we describe the presenting symptoms and clinical course of a Chinese boy with intermittent MSUD. Mutation analysis identified two previously unreported mutations in exon 7 of the BCKDHB gene: c.767A > G (p.Y256C) and c.768C > G (p.Y256X); the parents were each heterozygous for one of these mutations. In silico analysis predicted Y256C probably affects protein structure; Y256X leads to a premature stop codon. This case demonstrates intermittent MSUD should be suspected in cases with symptoms of recurrent encephalopathy, especially ataxia or marked drowsiness, which usually present after the neonatal period and in conjunction with infection. symmetrical basal ganglia damage but normal myelination in the posterior limb will assist differential diagnosis; alloisoleucine is a useful diagnostic marker and mutation analysis may be of prognostic value. These novel mutations Y256C and Y256X result in the clinical manifestation of a variant form of MSUD, expanding the mutation spectrum of this disease.
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Affiliation(s)
- Yi Guo
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China, 400014.
| | - Liu Liming
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
| | - Li Jiang
- Department of Neurology, Children's Hospital of Chongqing Medical University, Chongqing, China, 400014.
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
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