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Kentab AY, Alsalloum Y, Labani M, Hudairi A, Hamad MH, Jamjoom DZ, Alwadei AH, Alhammad RM, Bashiri FA. Case Report: A rare treatable metabolic syndrome (Brown-Vialetto-Van Laere syndrome) masquerading as chronic inflammatory demyelinating polyneuropathy from Saudi Arabia. Front Pediatr 2024; 12:1377515. [PMID: 38745833 PMCID: PMC11091239 DOI: 10.3389/fped.2024.1377515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 04/12/2024] [Indexed: 05/16/2024] Open
Abstract
Background Brown-Vialetto-Van Laere (BVVL) syndrome is an extremely rare autosomal recessive progressive motoneuron disease that is caused by a defect in the riboflavin transporter genes SLC52A2 and SLC52A3. BVVL syndrome has a variable age of presentation, and it is characterized by progressive auditory neuropathy, bulbar palsy, stridor, muscle weakness, and respiratory compromise secondary to diaphragmatic and vocal cord paralysis. BVVL syndrome has a poor prognosis in the absence of treatment, including morbidity with quadriparesis and sensorineural hearing loss, with mortality in the younger age group. Early administration of riboflavin is associated with prolonged survival, low morbidity, and reversal of some clinical manifestations. Case presentation We describe an 18-month-old male infant with progressive pontobulbar palsy, loss of developmental milestones, and a clinical picture suggestive of chronic inflammatory demyelinating neuropathy. A nerve conduction study revealed axonal neuropathy, while molecular analysis revealed a homozygous mutation in one of the riboflavin transporter genes, SLC52A3, confirming BVVL syndrome. The patient needed long-term respiratory support and a gastrostomy tube to support feeding. With high-dose riboflavin supplementation, he experienced moderate recovery of motor function. Conclusion This report highlights the importance of considering BVVL syndrome in any patient who presents with the clinical phenotype of pontobulbar palsy and peripheral axonal neuropathy, as early riboflavin treatment may improve or halt disease progression, thus reducing the associated mortality and morbidity.
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Affiliation(s)
- Amal Y. Kentab
- Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Yara Alsalloum
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Mai Labani
- Pediatric Intensive Care Unit, Department of Pediatrics, King Khalid University Hospital, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Abrar Hudairi
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Muddathir H. Hamad
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Dima Z. Jamjoom
- Department of Radiology and Medical Imaging, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Ali H. Alwadei
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
- Pediatric Neurology Department, National Neuroscience Institute, King Fahd Medical City, Riyadh, Saudi Arabia
| | - Reem M. Alhammad
- Department of Internal Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Fahad A. Bashiri
- Division of Pediatric Neurology, Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
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2
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Jin C, Yonezawa A. Recent advances in riboflavin transporter RFVT and its genetic disease. Pharmacol Ther 2021; 233:108023. [PMID: 34662687 DOI: 10.1016/j.pharmthera.2021.108023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/30/2021] [Accepted: 10/12/2021] [Indexed: 12/20/2022]
Abstract
Riboflavin (vitamin B2) is essential for cellular growth and function. It is enzymatically converted to flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which participate in the metabolic oxidation-reduction reactions of carbohydrates, amino acids, and lipids. Human riboflavin transporters RFVT1, RFVT2, and RFVT3 have been identified and characterized since 2008. They are highly specific transporters of riboflavin. RFVT3 has functional characteristics different from those of RFVT1 and RFVT2. RFVT3 contributes to absorption in the small intestine, reabsorption in the kidney, and transport to the fetus in the placenta, while RFVT2 mediates the tissue distribution of riboflavin from the blood. Several mutations in the SLC52A2 gene encoding RFVT2 and the SLC52A3 gene encoding RFVT3 were found in patients with a rare neurological disorder known as Brown-Vialetto-Van Laere syndrome. These patients commonly present with bulbar palsy, hearing loss, muscle weakness, and respiratory symptoms in infancy or later in childhood. A decrease in plasma riboflavin levels has been observed in several cases. Recent studies on knockout mice and patient-derived cells have advanced the understanding of these mechanisms. Here, we summarize novel findings on RFVT1-3 and their genetic diseases and discuss their potential as therapeutic drugs.
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Affiliation(s)
- Congyun Jin
- Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan; Graduate School of Pharmaceutical Sciences, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan
| | - Atsushi Yonezawa
- Department of Clinical Pharmacology and Therapeutics, Kyoto University Hospital, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan; Graduate School of Pharmaceutical Sciences, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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3
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Marioli C, Magliocca V, Petrini S, Niceforo A, Borghi R, Petrillo S, La Rosa P, Colasuonno F, Persichini T, Piemonte F, Massey K, Tartaglia M, Moreno S, Bertini E, Compagnucci C. Antioxidant Amelioration of Riboflavin Transporter Deficiency in Motoneurons Derived from Patient-Specific Induced Pluripotent Stem Cells. Int J Mol Sci 2020; 21:E7402. [PMID: 33036493 PMCID: PMC7582490 DOI: 10.3390/ijms21197402] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/01/2020] [Accepted: 10/01/2020] [Indexed: 12/20/2022] Open
Abstract
Mitochondrial dysfunction is a key element in the pathogenesis of neurodegenerative disorders, such as riboflavin transporter deficiency (RTD). This is a rare, childhood-onset disease characterized by motoneuron degeneration and caused by mutations in SLC52A2 and SLC52A3, encoding riboflavin (RF) transporters (RFVT2 and RFVT3, respectively), resulting in muscle weakness, ponto-bulbar paralysis and sensorineural deafness. Based on previous findings, which document the contribution of oxidative stress in RTD pathogenesis, we tested possible beneficial effects of several antioxidants (Vitamin C, Idebenone, Coenzyme Q10 and EPI-743, either alone or in combination with RF) on the morphology and function of neurons derived from induced pluripotent stem cells (iPSCs) from two RTD patients. To identify possible improvement of the neuronal morphotype, neurite length was measured by confocal microscopy after β-III tubulin immunofluorescent staining. Neuronal function was evaluated by determining superoxide anion generation by MitoSOX assay and intracellular calcium (Ca2+) levels, using the Fluo-4 probe. Among the antioxidants tested, EPI-743 restored the redox status, improved neurite length and ameliorated intracellular calcium influx into RTD motoneurons. In conclusion, we suggest that antioxidant supplementation may have a role in RTD treatment.
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Affiliation(s)
- Chiara Marioli
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
| | - Valentina Magliocca
- Department of Science, University Roma Tre, 00146 Rome, Italy; (V.M.); (T.P.)
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Stefania Petrini
- Confocal Microscopy Core Facility, Research Laboratories, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy;
| | - Alessia Niceforo
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Rossella Borghi
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Sara Petrillo
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Piergiorgio La Rosa
- Department of Psychology, Division of Neuroscience, Sapienza University of Rome, 00185 Rome, Italy;
| | - Fiorella Colasuonno
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Tiziana Persichini
- Department of Science, University Roma Tre, 00146 Rome, Italy; (V.M.); (T.P.)
| | - Fiorella Piemonte
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Keith Massey
- Science Director, Cure RTD Foundation, 6228 Northaven Rd., Dallas, TX 75230, USA;
| | - Marco Tartaglia
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
| | - Sandra Moreno
- Department of Science, LIME, University Roma Tre, 00146 Rome, Italy;
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Diseases, Laboratory of Molecular Medicine, Department of Neuroscience, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (A.N.); (R.B.); (S.P.); (F.P.); (E.B.)
| | - Claudia Compagnucci
- Genetics and Rare Diseases Research Division, IRCCS Ospedale Pediatrico Bambino Gesù, 00146 Rome, Italy; (C.M.); (F.C.); (M.T.)
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Rabbani B, Bakhshandeh MK, Navaeifar MR, Abbaskhanian A, Soveizi M, Geravandpoor S, Mahdieh N. Brown-Vialetto-Van Laere syndrome and Fazio-Londe syndrome: A novel mutation and in silico analyses. J Clin Neurosci 2020; 72:342-349. [PMID: 31959559 DOI: 10.1016/j.jocn.2020.01.040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 01/05/2020] [Indexed: 10/25/2022]
Abstract
Brown-Vialetto-Van Laere syndrome, a rare neurological disorder is due to SLC52A3 mutations. Here, the SLC52A3 protein and its mutations are in silico structurally and functionally analyzed among all the reported patients and a novel mutation is also reported. After clinical evaluations, SLC52A3 gene was sequenced and segregation analysis of the mutations was also checked. A comprehensive search was performed on the reported mutations of SLC52A3 gene. In silico structural and functional analyses of the mutations and interactome analyses of the protein were done using available software tools. Mutations of 37 affected individuals were identified. Thirty three mutations were determined. c.502A > C was a novel variant that it was segregated within the family. One mutation (c.639C > G) was responsible for 12% of the mutations. Segregation analysis, secondary structure, functional prediction achieved for the novel mutation showed pathogenicity of this variant. BVVL is a very rare disorder; SLC52A3 mutations are distributed among different populations and there might be one frequent mutation in this gene. BVVL should be more considered in Iran. In addition to segregation analysis, computational analyses could accelerate understanding the extent of pathogenicity of the novel variants.
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Affiliation(s)
- Bahareh Rabbani
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Kazem Bakhshandeh
- Department of Pediatrics, Faculty of Medicine, Tehran Medical sciences, Islamic Azad university,Tehran, Iran
| | - Mohammad Reza Navaeifar
- Pediatric Infectious Diseases Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ali Abbaskhanian
- Pediatric Infectious Diseases Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahdieh Soveizi
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Shahpour Geravandpoor
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Nejat Mahdieh
- Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran; Growth and Development Research Center, Tehran University of Medical Sciences, Tehran, Iran; Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Tehran, Iran.
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O'Callaghan B, Bosch AM, Houlden H. An update on the genetics, clinical presentation, and pathomechanisms of human riboflavin transporter deficiency. J Inherit Metab Dis 2019; 42:598-607. [PMID: 30793323 DOI: 10.1002/jimd.12053] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/31/2018] [Indexed: 11/10/2022]
Abstract
Riboflavin transporter deficiency (RTD) is a rare neurological condition that encompasses the Brown-Vialetto-Van Laere and Fazio-Londe syndromes since the discovery of pathogenic mutations in the SLC52A2 and SLC52A3 genes that encode human riboflavin transporters RFVT2 and RFVT3. Patients present with a deteriorating progression of peripheral and cranial neuropathy that causes muscle weakness, vision loss, deafness, sensory ataxia, and respiratory compromise which when left untreated can be fatal. Considerable progress in the clinical and genetic diagnosis of RTDs has been made in recent years and has permitted the successful lifesaving treatment of many patients with high dose riboflavin supplementation. In this review, we first outline the importance of riboflavin and its efficient transmembrane transport in human physiology. Reports on 109 patients with a genetically confirmed diagnosis of RTD are then summarized in order to highlight commonly presenting clinical features and possible differences between patients with pathogenic SLC52A2 (RTD2) or SLC52A3 (RTD3) mutations. Finally, we focus attention on recent work with different models of RTD that have revealed possible pathomechanisms contributing to neurodegeneration in patients.
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Affiliation(s)
- Benjamin O'Callaghan
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
| | - Annet M Bosch
- Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Pediatric Metabolic Diseases, Amsterdam, The Netherlands
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology and National Hospital for Neurology and Neurosurgery, London, UK
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6
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Brown–Vialetto–Van Laere [BVVL] Syndrome. Neuromuscul Disord 2018. [DOI: 10.1007/978-981-10-5361-0_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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7
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Khadilkar SV, Faldu HD, Udani V, Patil SB, Malvadkar S. Reversible posterior column dysfunction in Brown-Vialetto-Von Laere syndrome. Muscle Nerve 2017; 56:E28-E31. [PMID: 28543375 DOI: 10.1002/mus.25694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Revised: 05/14/2017] [Accepted: 05/21/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Satish V Khadilkar
- Department of Neurology, Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India
| | - Hinaben Dayalal Faldu
- Department of Neurology, Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India
| | - Vrajesh Udani
- Department of Paediatrics, Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India
| | - Sarika B Patil
- Department of Neurology, Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India
| | - Sharad Malvadkar
- Department of Radiology, Grant Medical College and Sir J.J. Group of Hospitals, Mumbai, India
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Jaeger B, Bosch AM. Clinical presentation and outcome of riboflavin transporter deficiency: mini review after five years of experience. J Inherit Metab Dis 2016; 39:559-64. [PMID: 26973221 PMCID: PMC4920840 DOI: 10.1007/s10545-016-9924-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Riboflavin (vitamin B2) is absorbed in the small intestine by the human riboflavin transporters RFVT1 and RFVT3. A third riboflavin transporter (RFVT2) is expressed in the brain. In 2010 it was demonstrated that mutations in the riboflavin transporter genes SLC52A2 (coding for RFVT2) and SLC52A3 (coding for RFVT3) cause a neurodegenerative disorder formerly known as Brown-Vialetto-Van Laere (BVVL) syndrome, now renamed to riboflavin transporter deficiency. Five years after the diagnosis of the first patient we performed a review of the literature to study the presentation, treatment and outcome of patients with a molecularly confirmed diagnosis of a riboflavin transporter deficiency. METHOD A search was performed in Medline, Pubmed using the search terms 'Brown-Vialetto-Van Laere syndrome' and 'riboflavin transporter' and articles were screened for case reports of patients with a molecular diagnosis of a riboflavin transporter deficiency. RESULTS Reports on a total of 70 patients with a molecular diagnosis of a RFVT2 or RTVT3 deficiency were retrieved. The riboflavin transporter deficiencies present with weakness, cranial nerve deficits including hearing loss, sensory symptoms including sensory ataxia, feeding difficulties and respiratory difficulties which are caused by a sensorimotor axonal neuropathy and cranial neuropathy. Biochemical abnormalities may be absent and the diagnosis can only be made or rejected by molecular analysis of all genes. Treatment with oral supplementation of riboflavin is lifesaving. Therefore, if a riboflavin transporter deficiency is suspected, treatment must be started immediately without first awaiting the results of molecular diagnostics.
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Affiliation(s)
- Bregje Jaeger
- />Department of Pediatric Neurology, Emma Children’s Hospital, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| | - Annet M. Bosch
- />Department of Pediatrics, Emma Children’s Hospital, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
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Disruption of Slc52a3 gene causes neonatal lethality with riboflavin deficiency in mice. Sci Rep 2016; 6:27557. [PMID: 27272163 PMCID: PMC4897618 DOI: 10.1038/srep27557] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 05/18/2016] [Indexed: 12/03/2022] Open
Abstract
Homeostasis of riboflavin should be maintained by transporters. Previous in vitro studies have elucidated basic information about riboflavin transporter RFVT3 encoded by SLC52A3 gene. However, the contribution of RFVT3 to the maintenance of riboflavin homeostasis and the significance in vivo remain unclear. Here, we investigated the physiological role of RFVT3 using Slc52a3 knockout (Slc52a3−/−) mice. Most Slc52a3−/− mice died with hyperlipidemia and hypoglycemia within 48 hr after birth. The plasma and tissue riboflavin concentrations in Slc52a3−/− mice at postnatal day 0 were dramatically lower than those in wild-type (WT) littermates. Slc52a3−/− fetuses showed a lower capacity of placental riboflavin transport compared with WT fetuses. Riboflavin supplement during pregnancy and after birth reduced neonatal death and metabolic disorders. To our knowledge, this is the first report to indicate that Rfvt3 contributes to placental riboflavin transport, and that disruption of Slc52a3 gene caused neonatal mortality with hyperlipidemia and hypoglycemia owing to riboflavin deficiency.
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Intoh A, Suzuki N, Koszka K, Eggan K. SLC52A3, A Brown-Vialetto-van Laere syndrome candidate gene is essential for mouse development, but dispensable for motor neuron differentiation. Hum Mol Genet 2016; 25:1814-23. [PMID: 26976849 DOI: 10.1093/hmg/ddw053] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 02/15/2016] [Indexed: 11/13/2022] Open
Abstract
Riboflavin, also known as vitamin B2, is essential for cellular reduction-oxidation reactions, but is not readily synthesized by mammalian cells. It has been proposed that riboflavin absorption occurs through solute carrier family 52 members (SLC52) A1, A2 and A3. These transporters are also candidate genes for the childhood onset-neural degenerative syndrome Brown-Vialetto-Van Laere (BVVL). Although riboflavin is an essential nutrient, why mutations in its transporters result in a neural cell-specific disorder remains unclear. Here, we provide evidence that Slc52a3 is the mouse ortholog of SLC52A3 and show that Slc52a3 deficiency results in early embryonic lethality. Loss of mutant embryos was associated with both defects in placental formation and increased rates of apoptosis in embryonic cells. In contrast, Slc52a3 -/- embryonic stem cell lines could be readily established and differentiated into motor neurons, suggesting that this transporter is dispensable for neural differentiation and short-term maintenance. Consistent with this finding, examination of Slc52a3 gene products in adult tissues revealed expression in the testis and intestine but little or none in the brain and spinal cord. Our results suggest that BVVL patients with SCL52A3 mutations may be good candidates for riboflavin replacement therapy and suggests that either the mutations these individuals carry are hypomorphic, or that in these cases alternative transporters act during human embryogenesis to allow full-term development.
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Affiliation(s)
- Atsushi Intoh
- Department of Stem Cell and Regenerative Biology, The Harvard Stem Cell Institute, Harvard University, Sherman Fairchild Building, 7 Divinity Avenue, Cambridge, MA 02138, USA and
| | - Naoki Suzuki
- Department of Stem Cell and Regenerative Biology, The Harvard Stem Cell Institute, Harvard University, Sherman Fairchild Building, 7 Divinity Avenue, Cambridge, MA 02138, USA and
| | - Kathryn Koszka
- Department of Stem Cell and Regenerative Biology, The Harvard Stem Cell Institute, Harvard University, Sherman Fairchild Building, 7 Divinity Avenue, Cambridge, MA 02138, USA and
| | - Kevin Eggan
- Department of Stem Cell and Regenerative Biology, The Harvard Stem Cell Institute, Harvard University, Sherman Fairchild Building, 7 Divinity Avenue, Cambridge, MA 02138, USA and The Stanley Center for Psychiatric Research, Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
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12
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Peeters K, Chamova T, Jordanova A. Clinical and genetic diversity of SMN1-negative proximal spinal muscular atrophies. ACTA ACUST UNITED AC 2014; 137:2879-96. [PMID: 24970098 PMCID: PMC4208460 DOI: 10.1093/brain/awu169] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Peeters et al. review current knowledge regarding the phenotypes, causative genes, and disease mechanisms associated with proximal SMN1-negative spinal muscular atrophies (SMA). They describe the molecular and cellular functions enriched among causative genes, and discuss the challenges facing the post-genomics era of SMA research. Hereditary spinal muscular atrophy is a motor neuron disorder characterized by muscle weakness and atrophy due to degeneration of the anterior horn cells of the spinal cord. Initially, the disease was considered purely as an autosomal recessive condition caused by loss-of-function SMN1 mutations on 5q13. Recent developments in next generation sequencing technologies, however, have unveiled a growing number of clinical conditions designated as non-5q forms of spinal muscular atrophy. At present, 16 different genes and one unresolved locus are associated with proximal non-5q forms, having high phenotypic variability and diverse inheritance patterns. This review provides an overview of the current knowledge regarding the phenotypes, causative genes, and disease mechanisms associated with proximal SMN1-negative spinal muscular atrophies. We describe the molecular and cellular functions enriched among causative genes, and discuss the challenges in the post-genomics era of spinal muscular atrophy research.
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Affiliation(s)
- Kristien Peeters
- 1 Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, University of Antwerp, Antwerpen 2610, Belgium 2 Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerpen 2610, Belgium
| | - Teodora Chamova
- 3 Department of Neurology, Medical University-Sofia, Sofia 1000, Bulgaria
| | - Albena Jordanova
- 1 Molecular Neurogenomics Group, Department of Molecular Genetics, VIB, University of Antwerp, Antwerpen 2610, Belgium 2 Neurogenetics Laboratory, Institute Born-Bunge, University of Antwerp, Antwerpen 2610, Belgium 4 Department of Medical Chemistry and Biochemistry, Molecular Medicine Centre, Medical University-Sofia, Sofia 1431, Bulgaria
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Spagnoli C, Pitt MC, Rahman S, de Sousa C. Brown-Vialetto-van Laere syndrome: a riboflavin responsive neuronopathy of infancy with singular features. Eur J Paediatr Neurol 2014; 18:231-4. [PMID: 24206674 DOI: 10.1016/j.ejpn.2013.09.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 08/29/2013] [Accepted: 09/23/2013] [Indexed: 11/29/2022]
Abstract
We report the case of a previously healthy child presenting at 6 months of age with mild feeding difficulties and then developing hypotonia, progressive bulbar palsy with respiratory compromise and lower motor neuron signs, causing her to spend 4 months in the Paediatric Intensive Care Unit. Neurophysiological studies demonstrated a motor neuronopathy involving anterior horn cells and cranial nerve nuclei and abnormal brainstem auditory evoked potentials, leading to a diagnosis of Brown-Vialetto-van Laere Syndrome, confirmed by genetic testing (SLC52A3). Magnetic Resonance Imaging showed signal changes in the dorsal column of the spinal cord. She developed a coarse face and abnormal hair pattern. Sustained clinical improvement has been observed during almost 4 years of high-dose riboflavin therapy.
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Affiliation(s)
- Carlotta Spagnoli
- Neurology Department, Great Ormond Street Hospital for Children, London, UK.
| | - Matthew C Pitt
- Neurophysiology Department, Great Ormond Street Hospital for Children, London, UK
| | - Shamima Rahman
- Metabolic Department, Great Ormond Street Hospital for Children, London, UK; Mitochondrial Research Group, UCL Institute of Child Health, London, UK
| | - Carlos de Sousa
- Neurology Department, Great Ormond Street Hospital for Children, London, UK
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Abstract
PURPOSE OF REVIEW It is easy to forget the contribution of electromyography (EMG) to the investigation of paediatric peripheral neuromuscular disease, and this review highlights its continued importance. RECENT FINDINGS The discovery that Brown-Vialetto-van Leare disease, when associated with disorder of riboflavin metabolism, may be treatable has raised awareness of the importance of EMG for its early detection. Unexpected discovery of motor neuronopathy, which may be useful for the definition of the phenotype of several conditions, now has an added significance. The investigation of disorders of peripheral nerve cannot proceed without nerve conduction studies but particular interest has been shown in its role in the management of obstetric brachial plexus palsy, with investigation within 1 month now recommended. The key role of neurophysiology in identifying abnormalities of the neuromuscular junction, and therefore leading investigators to a diagnosis of myasthenia, is once again highlighted. EMG in muscle disease continues to have a role, particularly when identifying myotonia. SUMMARY Paediatric EMG, while a daunting technical challenge to some practitioners, remains a valuable investigative tool for the specialists in paediatric neuromuscular disorders and will continue to deliver important diagnostic information, often as quickly and accurately as other more recent innovations.
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Lienhart WD, Gudipati V, Macheroux P. The human flavoproteome. Arch Biochem Biophys 2013; 535:150-62. [PMID: 23500531 PMCID: PMC3684772 DOI: 10.1016/j.abb.2013.02.015] [Citation(s) in RCA: 152] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/21/2013] [Accepted: 02/23/2013] [Indexed: 11/26/2022]
Abstract
Vitamin B2 (riboflavin) is an essential dietary compound used for the enzymatic biosynthesis of FMN and FAD. The human genome contains 90 genes encoding for flavin-dependent proteins, six for riboflavin uptake and transformation into the active coenzymes FMN and FAD as well as two for the reduction to the dihydroflavin form. Flavoproteins utilize either FMN (16%) or FAD (84%) while five human flavoenzymes have a requirement for both FMN and FAD. The majority of flavin-dependent enzymes catalyze oxidation-reduction processes in primary metabolic pathways such as the citric acid cycle, β-oxidation and degradation of amino acids. Ten flavoproteins occur as isozymes and assume special functions in the human organism. Two thirds of flavin-dependent proteins are associated with disorders caused by allelic variants affecting protein function. Flavin-dependent proteins also play an important role in the biosynthesis of other essential cofactors and hormones such as coenzyme A, coenzyme Q, heme, pyridoxal 5'-phosphate, steroids and thyroxine. Moreover, they are important for the regulation of folate metabolites by using tetrahydrofolate as cosubstrate in choline degradation, reduction of N-5.10-methylenetetrahydrofolate to N-5-methyltetrahydrofolate and maintenance of the catalytically competent form of methionine synthase. These flavoenzymes are discussed in detail to highlight their role in health and disease.
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Affiliation(s)
| | | | - Peter Macheroux
- Graz University of Technology, Institute of Biochemistry, Petersgasse 12, A-8010 Graz, Austria
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Bosch AM, Stroek K, Abeling NG, Waterham HR, Ijlst L, Wanders RJA. The Brown-Vialetto-Van Laere and Fazio Londe syndrome revisited: natural history, genetics, treatment and future perspectives. Orphanet J Rare Dis 2012; 7:83. [PMID: 23107375 PMCID: PMC3517535 DOI: 10.1186/1750-1172-7-83] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 10/23/2012] [Indexed: 11/24/2022] Open
Abstract
The Brown-Vialetto-Van Laere syndrome is a rare neurological disorder which may present at all ages with sensorineural deafness, bulbar palsy and respiratory compromise. Fazio-Londe syndrome is considered to be the same disease entity. Recently it was demonstrated that in some patients the disease is caused by mutations in the SLC52A3 gene which encodes the intestinal (hRFT2) riboflavin transporter. In these patients riboflavin deficiency is the cause of the BVVL/FL syndrome and supplementation of riboflavin proved a life saving treatment. Mutations in the SLC52A2 gene and the SLC52A1 (GPR172B) gene, coding for human riboflavin transporters hRFT3 and hRFT1 have been associated with the BVVL syndrome as well. We performed a review of the literature, with emphasis on the natural history and the effects of treatment in these patients. A total of 35 publications were traced reporting on the clinical presentation of 74 patients who presented before age 18. The most prevalent symptoms were bulbar palsy, hearing loss, facial weakness and respiratory compromise. Death was reported in 28 of the 61 untreated patients, with a very low survival in patients presenting before age 4. All 13 patients who were treated with riboflavin survived, with a strong clinical improvement after days to months of treatment in eight patients. Three patients demonstrated a stable clinical course and treatment was stopped early in two patients. Abnormalities in plasma flavin levels and/or plasma acylcarnitine profiles were observed in some but not in all patients, and also patients with normal plasma flavin levels and acylcarnitine profiles demonstrated a striking clinical improvement on riboflavin supplementation. It is now clear that proper diagnosis requires mutation analysis of all three transporter genes and treatment should be started immediately without first awaiting results of molecular analysis. Clinical improvement may be rapid or gradual over a period of more than 12 months.
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Affiliation(s)
- Annet M Bosch
- Department of Pediatrics, University of Amsterdam, Amsterdam, The Netherlands.
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