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Myszkowska J, Klotz K, Leandro P, Kruger WD, Froese DS, Baumgartner MR, Spiekerkoetter U, Hannibal L. Real-time detection of enzymatically formed hydrogen sulfide by pathogenic variants of cystathionine beta-synthase using hemoglobin I of Lucina pectinata as a biosensor. Free Radic Biol Med 2024:S0891-5849(24)00577-X. [PMID: 39067625 DOI: 10.1016/j.freeradbiomed.2024.07.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Revised: 06/23/2024] [Accepted: 07/24/2024] [Indexed: 07/30/2024]
Abstract
Classical homocystinuria is a rare disease caused by mutations in cystathionine β-synthase( CBS) gene (OMIM 613381). CBS catalyzes the first step of the transsulfuration pathway that converts homocysteine (Hcy) into cystathionine (Cysta) via a number of co-substrates and mechanisms. Formation of Cysta by condensation of Hcy and cysteine (Cys) produces a molar equivalent of hydrogen sulfide (H2S). H2S plays important roles in cognitive and vascular functions. Clinically, patients with CBS deficiency present with vascular, ocular, neurological and skeletal impairments. Biochemically, CBS deficiency manifests with elevated Hcy and reduced concentration of Cysta in plasma and urine. A number of pathogenic variants of human CBS have been characterized by their residual enzymatic activity, but very few studies have examined H2S production by pathogenic CBS variants, possibly due to technical hurdles in H2S detection and quantification. We describe a method for the real-time, continuous quantification of H2S formed by wild-type and pathogenic variants of human recombinant CBS, as well as by fibroblast extracts from healthy controls and patients diagnosed with CBS deficiency. The method takes advantage of the specificity and high affinity of hemoglobin I of the clam Lucina pectinata toward H2S and is based on UV-visible spectrophotometry. Comparison with the gold-standard, end-point H2S quantification method employing monobromobimane, as well as correlations with CBS enzymatic activity determined by LC-MS/MS showed agreement and correlation, and permitted the direct, time-resolved determination of H2S production rates by purified human recombinant CBS and by CBS present in fibroblast extracts. Rates of H2S production were highest for wild-type CBS, and lower for pathogenic variants. This method enables the examination of structural determinants of CBS that are important for H2S production and its possible relevance to the clinical outcome of patients.
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Affiliation(s)
- Joanna Myszkowska
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center, University of Freiburg, 79106 Freiburg, Germany
| | - Katharina Klotz
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center, University of Freiburg, 79106 Freiburg, Germany
| | - Paula Leandro
- Research Institute for Medicines, Faculty of Pharmacy, Universidade de Lisboa. Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal
| | - Warren D Kruger
- Fox Chase Cancer Center, 333 Cottman Ave., Philadelphia, PA 19111, USA
| | - D Sean Froese
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, University of Zurich, 8032, Zurich, Switzerland
| | - Matthias R Baumgartner
- Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, University of Zurich, 8032, Zurich, Switzerland
| | - Ute Spiekerkoetter
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center, University of Freiburg, 79106 Freiburg, Germany
| | - Luciana Hannibal
- Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, Faculty of Medicine, Medical Center, University of Freiburg, 79106 Freiburg, Germany.
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Jiang X, Shen D, Yang X, Lu Z, Huang H, Zhang B, Ma H. CBS and SERPINC1 mutation-induced ischemic stroke and multisystem diseases in a young woman: a case description and literature analysis. Quant Imaging Med Surg 2023; 13:5423-5429. [PMID: 37581074 PMCID: PMC10423349 DOI: 10.21037/qims-23-255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 06/02/2023] [Indexed: 08/16/2023]
Affiliation(s)
- Xuanfei Jiang
- Department of Neurology, Huzhou Cent Hospital, the Affiliated Cent Hospital Huzhou University, Huzhou, China
| | - Dan Shen
- Longxi Street Community Health Service Center, Huzhou, China
| | - Xiangyan Yang
- Department of Neurology, Huzhou Cent Hospital, the Affiliated Cent Hospital Huzhou University, Huzhou, China
| | - Zhenchan Lu
- Department of Neurology, Huzhou Cent Hospital, the Affiliated Cent Hospital Huzhou University, Huzhou, China
| | - Huan Huang
- Department of Neurology, Huzhou Cent Hospital, the Affiliated Cent Hospital Huzhou University, Huzhou, China
| | - Bing Zhang
- Department of Neurology, Huzhou Cent Hospital, the Affiliated Cent Hospital Huzhou University, Huzhou, China
| | - Honggang Ma
- Department of Neurology, Huzhou Cent Hospital, the Affiliated Cent Hospital Huzhou University, Huzhou, China
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Aleshin VA, Bunik VI. Protein-Protein Interfaces as Druggable Targets: A Common Motif of the Pyridoxal-5'-Phosphate-Dependent Enzymes to Receive the Coenzyme from Its Producers. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:1022-1033. [PMID: 37751871 DOI: 10.1134/s0006297923070131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/22/2023] [Accepted: 04/10/2023] [Indexed: 09/28/2023]
Abstract
Pyridoxal-5'-phosphate (PLP), a phosphorylated form of vitamin B6, acts as a coenzyme for numerous reactions, including those changed in cancer and/or associated with the disease prognosis. Since highly reactive PLP can modify cellular proteins, it is hypothesized to be directly transferred from its donors to acceptors. Our goal is to validate the hypothesis by finding common motif(s) in the multitude of PLP-dependent enzymes for binding the limited number of PLP donors, namely pyridoxal kinase (PdxK), pyridox(am)in-5'-phosphate oxidase (PNPO), and PLP-binding protein (PLPBP). Experimentally confirmed interactions between the PLP donors and acceptors reveal that PdxK and PNPO interact with the most abundant PLP acceptors belonging to structural folds I and II, while PLPBP - with those belonging to folds III and V. Aligning sequences and 3D structures of the identified interactors of PdxK and PNPO, we have identified a common motif in the PLP-dependent enzymes of folds I and II. The motif extends from the enzyme surface to the neighborhood of the PLP binding site, represented by an exposed alfa-helix, a partially buried beta-strand, and residual loops. Pathogenicity of mutations in the human PLP-dependent enzymes within or in the vicinity of the motif, but outside of the active sites, supports functional significance of the motif that may provide an interface for the direct transfer of PLP from the sites of its synthesis to those of coenzyme binding. The enzyme-specific amino acid residues of the common motif may be useful to develop selective inhibitors blocking PLP delivery to the PLP-dependent enzymes critical for proliferation of malignant cells.
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Affiliation(s)
- Vasily A Aleshin
- Department of Biokinetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia
- Department of Biochemistry, Sechenov University, Moscow, 119048, Russia
| | - Victoria I Bunik
- Department of Biokinetics, Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119234, Russia.
- Department of Biochemistry, Sechenov University, Moscow, 119048, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119234, Russia
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Bittmann S, Villalon G, Moschuring-Alieva E, Luchter E, Bittmann L. Current and Novel Therapeutical Approaches of Classical Homocystinuria in Childhood With Special Focus on Enzyme Replacement Therapy, Liver-Directed Therapy and Gene Therapy. J Clin Med Res 2023; 15:76-83. [PMID: 36895619 PMCID: PMC9990725 DOI: 10.14740/jocmr4843] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 01/09/2023] [Indexed: 03/05/2023] Open
Abstract
Classical homocystinuria is a hereditary defect of the enzyme cystathionine beta synthase, which is produced in the liver. If this enzyme fails, the synthesis pathway of cysteine from methionine is interrupted, leading to the accumulation of homocysteine in the blood plasma and homocysteine in the urine. After birth, the children are unremarkable except for the characteristic laboratory findings. Symptoms rarely appear before the second year of life. The most common symptom is a prolapse of the crystalline lens. This finding is seen in 70% of untreated 10-year-old affected individuals. As the earliest symptom, psychomotor retardation occurs in the majority of patients already during the first two years of life. Limiting factors in terms of life expectancy are thromboembolism, peripheral arterial disease, myocardial infarction, and stroke. These symptoms are due to the damage to the vessels caused by the elevated amino acid levels. About 30% suffer a thromboembolic event by the age of 20, about half by the age of 30. This review focus on present and new therapeutical approaches like the role of enzyme replacement with presentation of different novel targets in research like pegtibatinase, pegtarviliase, CDX-6512, erymethionase, chaperones, proteasome inhibitors and probiotic treatment with SYNB 1353. Furthermore, we analyze the role of liver-directed therapy with three dimensional (3D) bioprinting, liver bioengineering of liver organoids in vitro and liver transplantation. The role of different gene therapy options to treat and cure this extremely rare disease in childhood will be discussed.
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Affiliation(s)
- Stefan Bittmann
- Ped Mind Institute, Department of Pediatrics, Medical and Finance Center Epe, D-48599 Gronau, Germany
| | - Gloria Villalon
- Ped Mind Institute, Department of Pediatrics, Medical and Finance Center Epe, D-48599 Gronau, Germany
| | - Elena Moschuring-Alieva
- Ped Mind Institute, Department of Pediatrics, Medical and Finance Center Epe, D-48599 Gronau, Germany
| | - Elisabeth Luchter
- Ped Mind Institute, Department of Pediatrics, Medical and Finance Center Epe, D-48599 Gronau, Germany
| | - Lara Bittmann
- Ped Mind Institute, Department of Pediatrics, Medical and Finance Center Epe, D-48599 Gronau, Germany
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Kruger WD. How to fix a broken protein: restoring function to mutant human cystathionine β-synthase. Hum Genet 2021; 141:1299-1308. [PMID: 34636997 DOI: 10.1007/s00439-021-02386-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/05/2021] [Indexed: 12/17/2022]
Abstract
Inborn errors of metabolism (IEM) comprise a large class of recessive genetic diseases involving disorders of cellular metabolism that tend to be caused by missense mutations in which a single incorrect amino acid is substituted in the polypeptide chain. Cystathionine beta-synthase (CBS) deficiency is an example of an IEM that causes large elevations of blood total homocysteine levels, resulting in phenotypes in several tissues. Current treatment strategies involve dietary restriction and vitamin therapy, but these are only partially effective and do not work in all patients. Over 85% of the described mutations in CBS-deficient patients are missense mutations in which the mutant protein fails to fold into an active conformation. The ability of CBS to achieve an active conformation is affected by a variety of intracellular protein networks including the chaperone system and the ubiquitin/proteasome system, collectively referred to as the proteostasis network. Proteostasis modulators are drugs that perturb various aspects of these networks. In this article, we will review the evidence that modulation of the intracellular protein folding environment can be used as a potential therapeutic strategy to treat CBS deficiency and discuss the pros and cons of such a strategy.
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Affiliation(s)
- Warren D Kruger
- Cancer Signaling and Epigenetics Program, Fox Chase Cancer Center, Philadelphia, PA, USA.
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Xu M, Li K, He W. Compound heterozygous mutations in the LTBP2 gene associated with microspherophakia in a Chinese patient: a case report and literature review. BMC Med Genomics 2021; 14:227. [PMID: 34535142 PMCID: PMC8449461 DOI: 10.1186/s12920-021-01080-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 09/09/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Microspherophakia (MSP, OMIM 251,750) is a rare inherited autosomal recessive eye disorder characterized by small spherically shaped lens. Several studies have indicated that the transforming growth factor-beta (TGF-beta) binding proteins(LTBP2) gene mutation is the predominant cause of MSP. In our study, novel compound heterozygous mutations in the LTBP2 gene associated with MSP were reported, which was different from previous reported homozygous mutations. CASE PRESENTATION The proband was an 18-year-old male in Western China with bilateral MSP, accompanied by ectopia lentis, secondary glaucoma and blindness in both eyes. In our hospital, he received bilateral lens resection and trabeculectomy combined with peripheral iridotomy. Using next-generation sequencing (NGS)-based gene panel tests, we identified pathogenic mutations in the peripheral blood DNA sample from the proband: c.3614_3618dupCTGGC (exon24, NM_000428) and c.2819G > A (exon18, NM_000428). The presence of the novel compound heterozygous mutations in the LTBP2 gene was linked with the development of MSP. Sanger sequencing confirmed the existence of one of the two variants in each parent respectively. CONCLUSION Our results demonstrated a rare case of MSP phenotype associated with novel compound heterozygous mutations in the LTBP2 gene using NGS technology.
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Affiliation(s)
- Manhua Xu
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610000, Sichuan Province, China
- Affiliated Hospital of Southwest Medical University, No.25, Taiping Street, Jiangyang District, Luzhou, 646000, Sichuan Province, China
| | - Kaiming Li
- Affiliated Hospital of Southwest Medical University, No.25, Taiping Street, Jiangyang District, Luzhou, 646000, Sichuan Province, China
| | - Weimin He
- Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610000, Sichuan Province, China.
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Saba N, Irshad S. Congenital cataract: An ocular manifestation of classical homocystinuria. Mol Genet Genomic Med 2021; 9:e1742. [PMID: 34342182 PMCID: PMC8457696 DOI: 10.1002/mgg3.1742] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/26/2021] [Accepted: 06/15/2021] [Indexed: 11/23/2022] Open
Abstract
Background Homocystinuria is an autosomal recessive metabolic disorder occurring due to the defects in cystathionine‐β‐synthase enzyme. The study was carried out to investigate a Pakistani family presenting bilateral congenital cataract with symptoms of classical homocystinuria at LRBT Free Eye Hospital, Lahore, Pakistan. Methods Three affected individuals of the family presented skeletal deformations, intellectual disability, speech delay, and myopia with bilateral congenital cataract. Genetic analysis on DNA samples from affected individuals was done through whole exome sequencing to identify underlying genetic variant causing disease phenotypes in the family. In silico analysis was done to predict the effect of variation on the structure of mutant protein. Results A missense allelic variant (NM_000071.3: c.253G>A) of the CBS gene was revealed which may affect the catalytic activity of the substituted (NP_000062.1: p.G85R) protein by disrupting the folding of the enzymatic protein. High levels of homocysteine were observed in the plasma of affected individuals. This is the first report of this genetic variant from Pakistan causing homocystinuria and congenital cataract in association. Conclusion This variant was reported first time in association with congenital cataract instead of ectopia lentis. Congenital cataract was developed secondarily in these patients and provided a clue for the early diagnosis of metabolic disorders like homocystinuria to prevent further complications and morbidity.
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Affiliation(s)
- Neelam Saba
- School of Biochemistry and Biotechnology, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan
| | - Saba Irshad
- School of Biochemistry and Biotechnology, University of the Punjab, Quaid-e-Azam Campus, Lahore, Pakistan
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Wasim M, Khan HN, Ayesha H, Tawab A, Habib FE, Asi MR, Iqbal M, Awan FR. High levels of blood glutamic acid and ornithine in children with intellectual disability. INTERNATIONAL JOURNAL OF DEVELOPMENTAL DISABILITIES 2020; 68:609-614. [PMID: 36210897 PMCID: PMC9542416 DOI: 10.1080/20473869.2020.1858520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 11/28/2020] [Accepted: 11/28/2020] [Indexed: 06/16/2023]
Abstract
Objectives: Aminoacidopathies are inborn errors of metabolism (IEMs) that cause intellectual disability in children. Luckily, aminoacidopathies are potentially treatable, if diagnosed earlier in life. The focus of this study was the screening of aminoacidopathies in a cohort of patients suspected for IEMs. Methods: Blood samples from healthy (IQ > 90; n = 391) and intellectually disabled (IQ < 70; n = 409) children (suspected for IEMs) were collected from different areas of Northern Punjab, Pakistan. An analytical HPLC assay was used for the screening of plasma amino acids. Results: All the samples (n = 800) were analyzed on HPLC and forty-three out of 409 patient samples showed abnormal amino acid profiles mainly in the levels of glutamic acid, ornithine and methionine. Plasma concentration (Mean ± SD ng/mL) were significantly high in 40 patients for glutamic acid (patients: 165 ± 38 vs. controls: 57 ± 8, p < 0.00001) and ornithine (patients: 3177 ± 937 vs. controls: 1361 ± 91, p < 0.0001). Moreover, 3 patients showed abnormally high (53.3 ± 8.6 ng/mL) plasma levels of methionine. Conclusion: In conclusion, biochemical analysis of samples from such patients at the metabolites level could reveal the underlying diseases which could be confirmed through advanced biochemical and genetic analyses. Thus, treatment to some of such patients could be offered. Thus burden of intellectual disability caused by such rare metabolic diseases could be reduced from the target populations.
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Affiliation(s)
- Muhammad Wasim
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Pakistan
| | - Haq Nawaz Khan
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Pakistan
| | - Hina Ayesha
- Department of Pediatrics, DHQ/Allied Hospitals, Punjab Medical College (PMC, Faisalabad Medical University (FMU), Faisalabad, Pakistan
| | - Abdul Tawab
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Pakistan
| | - Fazal e Habib
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | | | - Mazhar Iqbal
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Pakistan
| | - Fazli Rabbi Awan
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
- Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Pakistan
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Kalil MAB, Donis KC, Poswar FDO, Dos Santos BB, Santos ÂBS, Schwartz IVD. Cardiovascular findings in classic homocystinuria. Mol Genet Metab Rep 2020; 25:100693. [PMID: 33335839 PMCID: PMC7734301 DOI: 10.1016/j.ymgmr.2020.100693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 11/26/2020] [Accepted: 11/27/2020] [Indexed: 01/21/2023] Open
Abstract
Objective describe cardiovascular findings from echocardiograms and electrocardiograms in patients with Classic Homocystinuria. Methods this retrospective exploratory study evaluated fourteen subjects with Classic Homocystinuria (median age = 27.3 years; male n = 8, B6-non-responsive n = 9 patients), recruited by convenience sampling from patients seen Hospital de Clínicas de Porto Alegre (Brazil), between January 1997 and July 2020. Data on clinical findings, echocardiogram and electrocardiogram were retrieved from medical records. Results Eight patients presented some abnormalities on echocardiogram (n = 6) or electrocardiogram (n = 5). The most frequent finding was mild tricuspid regurgitation (n = 3), followed by mitral valve prolapse, mild mitral regurgitation, enlarged left atrium and aortic valve sclerosis (n = 2 patients each). Aortic root ectasia was found in one patient. Venous thrombosis was reported in six patients: deep vein thrombosis of lower limbs (n = 3), ischaemic stroke (n = 1), cerebral venous sinus thrombosis (n = 1) and pulmonary vein thrombosis (n = 1). Conclusion mild valvulopathies seen to be common in patients with Classic Homocystinuria, but more studies regarding echocardiogram and electrocardiogram in this population are needed to draw absolute conclusions.
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Affiliation(s)
| | - Karina Carvalho Donis
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, RS, Brazil.,Post graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, RS, Brazil
| | | | - Bruna Bento Dos Santos
- Post graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, RS, Brazil
| | - Ângela Barreto Santiago Santos
- Post graduate Program in Cardiology, Universidade Federal do Rio Grande do Sul, RS, Brazil.,Cardiology Service, Hospital de Clínicas de Porto Alegre, RS, Brazil
| | - Ida Vanessa Doederlein Schwartz
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, RS, Brazil.,Post graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, RS, Brazil
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Dindo M, Mandrile G, Conter C, Montone R, Giachino D, Pelle A, Costantini C, Cellini B. The ILE56 mutation on different genetic backgrounds of alanine:glyoxylate aminotransferase: Clinical features and biochemical characterization. Mol Genet Metab 2020; 131:171-180. [PMID: 32792227 DOI: 10.1016/j.ymgme.2020.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/30/2020] [Accepted: 07/30/2020] [Indexed: 01/20/2023]
Abstract
Primary Hyperoxaluria type I (PH1) is a rare disease caused by mutations in the AGXT gene encoding alanine:glyoxylate aminotransferase (AGT), a liver enzyme involved in the detoxification of glyoxylate, the failure of which results in accumulation of oxalate and kidney stones formation. The role of protein misfolding in the AGT deficit caused by most PH1-causing mutations is increasingly being recognized. In addition, the genetic background in which a mutation occurs is emerging as a critical risk factor for disease onset and/or severity. Based on these premises, in this study we have analyzed the clinical, biochemical and cellular effects of the p.Ile56Asn mutation, recently described in a PH1 patient, as a function of the residue at position 11, a hot-spot for both polymorphic (p.Pro11Leu) and pathogenic (p.Pro11Arg) mutations. We have found that the p.Ile56Asn mutation induces a structural defect mostly related to the apo-form of AGT. The effects are more pronounced when the substitution of Ile56 is combined with the p.Pro11Leu and, at higher degree, the p.Pro11Arg mutation. As compared with the non-pathogenic forms, AGT variants display reduced expression and activity in mammalian cells. Vitamin B6, a currently approved treatment for PH1, can overcome the effects of the p.Ile56Asn mutation only when it is associated with Pro at position 11. Our results provide a first proof that the genetic background influences the effects of PH1-causing mutations and the responsiveness to treatment and suggest that molecular and cellular studies can integrate clinical data to identify the best therapeutic strategy for PH1 patients.
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Affiliation(s)
- Mirco Dindo
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Giorgia Mandrile
- Medical Genetics Unit, Department of Clinical and Biological Sciences, University of Torino, Orbassano (TO), Italy; Genetica e Thalassemia Unit, San Luigi University Hospital, Orbassano (TO), Italy
| | - Carolina Conter
- Department of Neurological, Biomedical, and Movement Sciences, University of Verona, Verona, Italy
| | - Rosa Montone
- Department of Neurological, Biomedical, and Movement Sciences, University of Verona, Verona, Italy
| | - Daniela Giachino
- Medical Genetics Unit, Department of Clinical and Biological Sciences, University of Torino, Orbassano (TO), Italy
| | - Alessandra Pelle
- Medical Genetics Unit, Department of Clinical and Biological Sciences, University of Torino, Orbassano (TO), Italy
| | - Claudio Costantini
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Barbara Cellini
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.
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Weber Hoss GR, Sperb-Ludwig F, Schwartz IVD, Blom HJ. Classical homocystinuria: A common inborn error of metabolism? An epidemiological study based on genetic databases. Mol Genet Genomic Med 2020; 8:e1214. [PMID: 32232970 PMCID: PMC7284035 DOI: 10.1002/mgg3.1214] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 02/25/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Biallelic pathogenic variants in CBS gene cause the most common form of homocystinuria, the classical homocystinuria (HCU). The worldwide prevalence of HCU is estimated to be 0.82:100,000 [95% CI, 0.39-1.73:100,000] according to clinical records and 1.09:100,000 [95% CI, 0.34-3.55:100,000] by neonatal screening. In this study, we aimed to estimate the minimal worldwide incidence of HCU. METHODS The 25 most common pathogenic alleles of HCU were identified through a literature review. The incidence of HCU was estimated based on the frequency of these common pathogenic alleles in a large genomic database (gnomAD). RESULTS The minimum worldwide incidence of HCU was estimated to be ~0.38:100,000, and the incidence was higher in Europeans non-Finnish (~0.72:100,000) and Latin Americans (~0.45:100,000) and lower in Africans (~0.20:100,000) and Asians (~0.02:100,000). CONCLUSION Our data are in accordance with the only published metanalysis on this topic. To our surprise, the observed incidence of HCU in Europeans was much lower than those described in articles exploring small populations from northern Europe but was similar to the incidence described on the basis of neonatal screening programs. In our opinion, this large dataset analyzed and its population coverage gave us greater precision in the estimation of incidence.
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Affiliation(s)
- Giovana R Weber Hoss
- BRAIN Laboratory, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Fernanda Sperb-Ludwig
- BRAIN Laboratory, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Ida V D Schwartz
- BRAIN Laboratory, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Post Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Henk J Blom
- Department of Clinical Genetics, Center for Lysosomal and Metabolic Diseases, ErasmusMC, Rotterdam, The Netherlands
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Al-Sadeq DW, Nasrallah GK. The Spectrum of Mutations of Homocystinuria in the MENA Region. Genes (Basel) 2020; 11:genes11030330. [PMID: 32245022 PMCID: PMC7140887 DOI: 10.3390/genes11030330] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/09/2020] [Accepted: 03/13/2020] [Indexed: 12/18/2022] Open
Abstract
Homocystinuria is an inborn error of metabolism due to the deficiency in cystathionine beta-synthase (CBS) enzyme activity. It leads to the elevation of both homocysteine and methionine levels in the blood and urine. Consequently, this build-up could lead to several complications such as nearsightedness, dislocated eye lenses, a variety of psychiatric and behavioral disorders, as well as vascular system complications. The prevalence of homocystinuria is around 1/200,000 births worldwide. However, its prevalence in the Gulf region, notably Qatar, is exceptionally high and reached 1:1800. To date, more than 191 pathogenic CBS mutations have been documented. The majority of these mutations were identified in Caucasians of European ancestry, whereas only a few mutations from African-Americans or Asians were reported. Approximately 87% of all CBS mutations are missense and do not target the CBS catalytic site, but rather result in unstable misfolded proteins lacking the normal biological function, designating them for degradation. The early detection of homocystinuria along with low protein and methionine-restricted diet is the best treatment approach for all types of homocystinuria patients. Yet, less than 50% of affected individuals show a significant reduction in plasma homocysteine levels after treatment. Patients who fail to lower the elevated homocysteine levels, through high protein-restricted diet or by B6 and folic acid supplements, are at higher risk for cardiovascular diseases, neurodegenerative diseases, neural tube defects, and other severe clinical complications. This review aims to examine the mutations spectrum of the CBS gene, the disease management, as well as the current and potential treatment approaches with a greater emphasis on studies reported in the Middle East and North Africa (MENA) region.
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Affiliation(s)
- Duaa W. Al-Sadeq
- Biomedical Research Center, Qatar University, P.O. Box 2713 Doha, Qatar
- College of Medicine, Member of QU Health, Qatar University, P.O. Box 2713 Doha, Qatar
- Correspondence: (G.K.N.); (D.W.A-S.); Tel.: +974-4403-6623 (D.W.A-S.); +974-4403-4817 (G.K.N.); Fax: +974-4403-1351 (G.K.N.)
| | - Gheyath K. Nasrallah
- Biomedical Research Center, Qatar University, P.O. Box 2713 Doha, Qatar
- Department of Biomedical Science, College of Health Sciences, Qatar University, P.O. Box 2713 Doha, Qatar
- Correspondence: (G.K.N.); (D.W.A-S.); Tel.: +974-4403-6623 (D.W.A-S.); +974-4403-4817 (G.K.N.); Fax: +974-4403-1351 (G.K.N.)
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Hoss GRW, Poloni S, Blom HJ, Schwartz IVD. Three Main Causes of Homocystinuria: CBS, cblC and MTHFR Deficiency. What do they Have in Common? JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2019. [DOI: 10.1590/2326-4594-jiems-2019-0007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
| | - Soraia Poloni
- Universidade Federal do Rio Grande do Sul, Brazil; Hospital de Clínicas de Porto Alegre, Brazil
| | - Henk J Blom
- University Medical Centre Amsterdam, Netherlands
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Price BR, Wilcock DM, Weekman EM. Hyperhomocysteinemia as a Risk Factor for Vascular Contributions to Cognitive Impairment and Dementia. Front Aging Neurosci 2018; 10:350. [PMID: 30429785 PMCID: PMC6220027 DOI: 10.3389/fnagi.2018.00350] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 10/16/2018] [Indexed: 12/19/2022] Open
Abstract
Behind only Alzheimer's disease, vascular contributions to cognitive impairment and dementia (VCID) is the second most common cause of dementia, affecting roughly 10-40% of dementia patients. While there is no cure for VCID, several risk factors for VCID, such as diabetes, hypertension, and stroke, have been identified. Elevated plasma levels of homocysteine, termed hyperhomocysteinemia (HHcy), are a major, yet underrecognized, risk factor for VCID. B vitamin deficiency, which is the most common cause of HHcy, is common in the elderly. With B vitamin supplementation being a relatively safe and inexpensive therapeutic, the treatment of HHcy-induced VCID would seem straightforward; however, preclinical and clinical data shows it is not. Clinical trials using B vitamin supplementation have shown conflicting results about the benefits of lowering homocysteine and issues have arisen over proper study design within the trials. Studies using cell culture and animal models have proposed several mechanisms for homocysteine-induced cognitive decline, providing other targets for therapeutics. For this review, we will focus on HHcy as a risk factor for VCID, specifically, the different mechanisms proposed for homocysteine-induced cognitive decline and the clinical trials aimed at lowering plasma homocysteine.
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Affiliation(s)
| | | | - Erica M. Weekman
- Department of Physiology, Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
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CBS
mutations are good predictors for B6-responsiveness: A study based on the analysis of 35 Brazilian Classical Homocystinuria patients. Mol Genet Genomic Med 2018; 6:861. [PMID: 30264510 PMCID: PMC6160707 DOI: 10.1002/mgg3.462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Poloni S, Hoss GW, Sperb-Ludwig F, Borsatto T, Doriqui MJR, Leão EK, Boa-Sorte N, Lourenço CM, Kim CA, de Souza CFM, Rocha H, Ribeiro M, Steiner CE, Moreno CA, Bernardi P, Valadares E, Artigalas O, Carvalho G, Wanderley HYC, D’Almeida V, Santana-da-Silva LC, Blom HJ, Schwartz IVD. Diagnosis and Management of Classical Homocystinuria in Brazil. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2018. [DOI: 10.1177/2326409818788900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Soraia Poloni
- Post-Graduation Program in Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Giovana W. Hoss
- Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Fernanda Sperb-Ludwig
- Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Taciane Borsatto
- Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | | | - Emília K.E.A Leão
- Complexo Hospitalar Professor Edgard Santos, Salvador, Brazil
- Universidade do Estado da Bahia, Salvador, Brazil
| | - Ney Boa-Sorte
- Complexo Hospitalar Professor Edgard Santos, Salvador, Brazil
- Universidade do Estado da Bahia, Salvador, Brazil
| | - Charles M. Lourenço
- Hospital das Clínicas de Ribeirão Preto, Ribeirão Preto, Brazil
- Centro Universitário Estácio de Ribeirão Preto, Ribeirão Preto, Brazil
| | | | | | - Helio Rocha
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcia Ribeiro
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | - Osvaldo Artigalas
- Hospital da Criança Conceição, GHC, Porto Alegre, Brazil
- Hospital Materno-Infantil Presidente Vargas, Porto Alegre, Brazil
| | | | | | - Vânia D’Almeida
- Department of Psychobiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | | | - Henk J. Blom
- Laboratory for Clinical Biochemistry and Metabolism, University Medical Center, Freiburg, Germany
| | - Ida V. D. Schwartz
- Post-Graduation Program in Medical Sciences, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
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Poloni S, Sperb-Ludwig F, Borsatto T, Weber Hoss G, Doriqui MJR, Embiruçu EK, Boa-Sorte N, Marques C, Kim CA, Fischinger Moura de Souza C, Rocha H, Ribeiro M, Steiner CE, Moreno CA, Bernardi P, Valadares E, Artigalas O, Carvalho G, Wanderley HYC, Kugele J, Walter M, Gallego-Villar L, Blom HJ, Schwartz IVD. CBS mutations are good predictors for B6-responsiveness: A study based on the analysis of 35 Brazilian Classical Homocystinuria patients. Mol Genet Genomic Med 2018; 6:160-170. [PMID: 29352562 PMCID: PMC5902399 DOI: 10.1002/mgg3.342] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 09/13/2017] [Accepted: 09/22/2017] [Indexed: 11/10/2022] Open
Abstract
Background Classical homocystinuria (HCU) is a monogenic disease caused by the deficient activity of cystathionine β‐synthase (CβS). The objective of this study was to identify the CBS mutations in Brazilian patients with HCU. Methods gDNA samples were obtained for 35 patients (30 families) with biochemically confirmed diagnosis of HCU. All exons and exon‐intron boundaries of CBS gene were sequenced. Gene expression analysis by qRT‐PCR was performed in six patients. Novel missense point mutations were expressed in E. coli by site‐directed mutagenesis. Results Parental consanguinity was reported in 16 families, and pyridoxine responsiveness in five (15%) patients. Among individuals from the same family, all presented the same phenotype. Both pathogenic mutations were identified in 29/30 patients. Twenty‐one different mutations were detected in nine exons and three introns; being six common mutations. Most prevalent were p.Ile278Thr (18.2%), p.Trp323Ter (11.3%), p.Thr191Met (11.3%), and c.828+1G>A (11.3%). Eight novel mutations were found [c.2T>C, c.209+1delG, c.284T>C, c.329A>T, c.444delG, c.864_868delGAG c.989_991delAGG, and c.1223+5G>T]. Enzyme activity in E. coli‐expressed mutations was 1.5% for c.329A>T and 17.5% for c.284T>C. qRT‐PCR analysis revealed reduced gene expression in all evaluated genotypes: [c.209+1delG; c.572C>T]; [c.2T>C; c.828+1G>A]; [c.828+1G>A; c.1126G>A]; [c.833T>C; c.989_991delAGG]; [c.1058C>T; c.146C>T]; and [c.444delG; c.444delG]. The expected phenotype according to the genotype (pyridoxine responsiveness) matched in all cases. Conclusions Most patients studied were pyridoxine nonresponsive and presented early manifestations, suggesting severe phenotypes. Many private mutations were observed, but the four most prevalent mutations together accounted for over 50% of mutated alleles. A good genotype–phenotype relationship was observed within families and for the four most common mutations.
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Affiliation(s)
- Soraia Poloni
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Fernanda Sperb-Ludwig
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Taciane Borsatto
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Giovana Weber Hoss
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | | | - Emília K Embiruçu
- Complexo Hospitalar Professor Edgard Santos, Universidade do Estado da Bahia, Salvador, Brazil.,Universidade do Estado da Bahia, Salvador, Brazil
| | - Ney Boa-Sorte
- Complexo Hospitalar Professor Edgard Santos, Universidade do Estado da Bahia, Salvador, Brazil.,Universidade do Estado da Bahia, Salvador, Brazil
| | - Charles Marques
- Hospital das Clínicas de Ribeirão Preto, Ribeirão Preto, Brazil
| | - Chong A Kim
- Universidade de São Paulo, São Paulo, Brazil
| | | | - Helio Rocha
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Marcia Ribeiro
- Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | - Osvaldo Artigalas
- Children's Hospital, Grupo Hospitalar Conceição, Porto Alegre, Brazil.,Genetics Unit, Hospital Materno-Infantil Presidente Vargas, Porto Alegre, Brazil
| | | | - Hector Y C Wanderley
- Escola Superior de Ciências da Santa Casa de Misericórdia de Vitória, Vitória, Brazil
| | - Johanna Kugele
- Laboratory for Clinical Biochemistry and Metabolism, University Medical Center, Freiburg, Germany
| | - Melanie Walter
- Laboratory for Clinical Biochemistry and Metabolism, University Medical Center, Freiburg, Germany
| | - Lorena Gallego-Villar
- Laboratory for Clinical Biochemistry and Metabolism, University Medical Center, Freiburg, Germany
| | - Henk J Blom
- Laboratory for Clinical Biochemistry and Metabolism, University Medical Center, Freiburg, Germany
| | - Ida Vanessa D Schwartz
- Post-Graduation Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Laboratory of Basic Research and Advanced Investigations in Neurosciences (BRAIN), Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
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