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Ni Q, Tang M, Chen X, Lu Y, Wu B, Wang H, Zhou W, Dong X. Fructose-1,6-bisphosphatase deficiency: estimation of prevalence in the Chinese population and analysis of genotype-phenotype association. Front Genet 2024; 15:1296797. [PMID: 39036704 PMCID: PMC11258016 DOI: 10.3389/fgene.2024.1296797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 06/11/2024] [Indexed: 07/23/2024] Open
Abstract
Objective Fructose-1,6-bisphosphatase deficiency (FBP1D) is a rare inborn error due to mutations in the FBP1 gene. The genetic spectrum of FBP1D in China is unknown, also nonspecific manifestations confuse disease diagnosis. We systematically estimated the FBP1D prevalence in Chinese and explored genotype-phenotype association. Methods We collected 101 FBP1 variants from our cohort and public resources, and manually curated pathogenicity of these variants. Ninety-seven pathogenic or likely pathogenic variants were used in our cohort to estimate Chinese FBP1D prevalence by three methods: 1) carrier frequency, 2) permutation and combination, 3) Bayesian framework. Allele frequencies (AFs) of these variants in our cohort, China Metabolic Analytics Project (ChinaMAP) and gnomAD were compared to reveal the different hotspots in Chinese and other populations. Clinical and genetic information of 122 FBP1D patients from our cohort and published literature were collected to analyze the genotype-phenotypes association. Phenotypes of 68 hereditary fructose intolerance (HFI) patients from our previous study were used to compare the phenotypic differences between these two fructose metabolism diseases. Results The estimated Chinese FBP1D prevalence was 1/1,310,034. In the Chinese population, c.490G>A and c.355G>A had significantly higher AFs than in the non-Finland European population, and c.841G>A had significantly lower AF value than in the South Asian population (all p values < 0.05). The genotype-phenotype association analyses showed that patients carrying homozygous c.841G>A were more likely to present increased urinary glycerol, carrying two CNVs (especially homozygous exon1 deletion) were often with hepatic steatosis, carrying compound heterozygous variants were usually with lethargy, and carrying homozygous variants were usually with ketosis and hepatic steatosis (all p values < 0.05). By comparing to phenotypes of HFI patients, FBP1D patients were more likely to present hypoglycemia, metabolic acidosis, and seizures (all p-value < 0.05). Conclusion The prevalence of FBP1D in the Chinese population is extremely low. Genetic sequencing could effectively help to diagnose FBP1D.
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Affiliation(s)
- Qi Ni
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, National Children’s Medical Center, Shanghai, China
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Meiling Tang
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Xiang Chen
- Division of Neonatology, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Yulan Lu
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Bingbing Wu
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Huijun Wang
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
| | - Wenhao Zhou
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, National Children’s Medical Center, Shanghai, China
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
- Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Xinran Dong
- Children’s Hospital and Institutes of Biomedical Sciences, Fudan University, National Children’s Medical Center, Shanghai, China
- Center for Molecular Medicine, Children’s Hospital of Fudan University, National Children’s Medical Center, Shanghai, China
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2
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Liang X, Liu X, Li W, Zhang L, Zhang B, Lai G, Zhao Y. A novel variant in the FBP1 gene causes fructose-1,6-bisphosphatase deficiency through increased ubiquitination. Arch Biochem Biophys 2023; 742:109619. [PMID: 37142076 DOI: 10.1016/j.abb.2023.109619] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/21/2023] [Accepted: 05/01/2023] [Indexed: 05/06/2023]
Abstract
Fructose-1,6-bisphosphatase (FBPase) deficiency is an autosomal recessive disorder characterized by impaired gluconeogenesis caused by mutations in the fructose-1,6-bisphosphatase 1 (FBP1) gene. The molecular mechanisms underlying FBPase deficiency caused by FBP1 mutations require investigation. Herein, we report the case of a Chinese boy with FBPase deficiency who presented with hypoglycemia, ketonuria, metabolic acidosis, and repeated episodes of generalized seizures that progressed to epileptic encephalopathy. Whole-exome sequencing revealed compound heterozygous variants, c.761A > G (H254R) and c.962C > T (S321F), in FBP1. The variants, especially the novel H254R, reduced protein stability and enzymatic activity in patient-derived leukocytes and transfected HepG2 and U251 cells. Mutant FBP1 undergoes enhanced ubiquitination and proteasomal degradation. NEDD4-2 was identified as an E3 ligase for FBP1 ubiquitination in transfected cells and the liver and brain of Nedd4-2 knockout mice. The H254R mutant FBP1 interacted with NEDD4-2 at significantly higher levels than the wild-type control. Our study identified a novel H254R variant of FBP1 underlying FBPase deficiency and elucidated the molecular mechanism underlying the enhanced NEDD4-2-mediated ubiquitination and proteasomal degradation of mutant FBP1.
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Affiliation(s)
- Xiaoyan Liang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, China; Department of Central Laboratory, Binzhou People's Hospital, Shandong, 256600, China
| | - Xiaoliang Liu
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, China
| | - Wenjing Li
- Department of Cardiology, Binzhou People's Hospital, Shandong, 256600, China
| | - Lu Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, China
| | - Bijun Zhang
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, China
| | - Guangrui Lai
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, China
| | - Yanyan Zhao
- Department of Clinical Genetics, Shengjing Hospital of China Medical University, Shenyang, 110004, China.
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3
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Bai Q, Liu Y, Wang CM, Wang JR, Feng Y, Ma X, Yang X, Shi YN, Zhang WJ. Hepatic but not Intestinal FBP1 Is Required for Fructose Metabolism and Tolerance. Endocrinology 2023; 164:bqad054. [PMID: 36964915 DOI: 10.1210/endocr/bqad054] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 03/16/2023] [Accepted: 03/22/2023] [Indexed: 03/26/2023]
Abstract
Fructose intolerance in mammals is caused by defects in fructose absorption and metabolism. Fructose-1,6-bisphosphatase 1 (FBP1) is a key enzyme in gluconeogenesis, and its deficiency results in hypoglycemia as well as intolerance to fructose. However, the mechanism about fructose intolerance caused by FBP1 deficiency has not been fully elucidated. Here, we demonstrate that hepatic but not intestinal FBP1 is required for fructose metabolism and tolerance. We generated inducible knockout mouse models specifically lacking FBP1 in adult intestine or liver. Intestine-specific deletion of Fbp1 in adult mice does not compromise fructose tolerance, as evidenced by no significant body weight loss, food intake reduction, or morphological changes of the small intestine during 4 weeks of exposure to a high-fructose diet. By contrast, liver-specific deletion of Fbp1 in adult mice leads to fructose intolerance, as manifested by substantial weight loss, hepatomegaly, and liver injury after exposure to a high-fructose diet. Notably, the fructose metabolite fructose-1-phosphate is accumulated in FBP1-deficient liver after fructose challenge, which indicates a defect of fructolysis, probably due to competitive inhibition by fructose-1,6-bisphosphate and may account for the fructose intolerance. In conclusion, these data have clarified the essential role of hepatic but not intestinal FBP1 in fructose metabolism and tolerance.
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Affiliation(s)
- Qiufang Bai
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Yajin Liu
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Chen-Ma Wang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Jue-Rui Wang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Yingying Feng
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
- Department of Pathophysiology, Naval Medical University, Shanghai 200433, China
| | - Xianhua Ma
- Department of Pathophysiology, Naval Medical University, Shanghai 200433, China
| | - Xiaohang Yang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Ya-Nan Shi
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
| | - Weiping J Zhang
- NHC Key Laboratory of Hormones and Development, Tianjin Key Laboratory of Metabolic Diseases, Chu Hsien-I Memorial Hospital & Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300134, China
- Department of Pathophysiology, Naval Medical University, Shanghai 200433, China
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Goetz M, Schröter J, Dattner T, Brennenstuhl H, Lenz D, Opladen T, Hörster F, Okun JG, Hoffmann GF, Kölker S, Staufner C. Genotypic and phenotypic spectrum of cytosolic phosphoenolpyruvate carboxykinase deficiency. Mol Genet Metab 2022; 137:18-25. [PMID: 35868242 DOI: 10.1016/j.ymgme.2022.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 10/17/2022]
Abstract
OBJECTIVES Pathogenic biallelic variants in PCK1 coding for the cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) cause PEPCK-C deficiency, a rare disorder of gluconeogenesis presenting with hypoglycemia, lactic acidosis, and hepatopathy. To date, there has been no systematic analysis of its phenotypic, biochemical, and genetic spectrum. METHODS All currently published individuals and a novel patient with genetically confirmed PEPCK-C deficiency were included. Clinical, biochemical, and genetic findings were analyzed. Protein and in-silico prediction score modeling was applied to analyze potential variant effects. RESULTS Thirty-two individuals from 25 families were found, including one previously unreported patient. The typical biochemical pattern was hypoglycemia triggered by catabolic situations, elevated urinary concentrations of tricarboxylic acid cycle metabolites, mildly elevated alanine and aspartate aminotransferase and elevated lactate concentrations in serum. Plasma glutamine concentrations were elevated in some patients and may be a suitable marker for newborn screening. With adequate treatment, biochemical abnormalities usually normalized following a hypoglycemic episode. Symptom onset usually occurred in infancy with a broad range from neonatal age to adulthood. Regardless of the genotype, different phenotypes with a broad clinical spectrum were found. To date, eight genotypes with nine different PCK1 variants were identified, of which alleles with the recurrent variant c.925G > A; p.(Gly309Arg) are predominant and appear to be endemic in the Finnish population. Protein modeling suggests altered manganese- and substrate-binding as superordinate pathomechanisms. CONCLUSIONS Environmental factors appear to be the main determinant for the phenotype in patients with biallelic variants in PCK1. Based on the biochemical pattern, PEPCK-C deficiency is a recognizable cause of childhood hypoglycemia. It is a treatable disease and early diagnosis is important to prevent metabolic derailment and morbidity. Newborn screening can identify at least a sub-cohort of affected individuals through elevated glutamine concentrations in dry blood.
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Affiliation(s)
- M Goetz
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - J Schröter
- Division of Pediatric Epileptology, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - T Dattner
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - H Brennenstuhl
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - D Lenz
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - T Opladen
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - F Hörster
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - J G Okun
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - G F Hoffmann
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - S Kölker
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - C Staufner
- Division of Child Neurology and Metabolic Disorders, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany..
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5
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Gorce M, Lebigot E, Arion A, Brassier A, Cano A, De Lonlay P, Feillet F, Gay C, Labarthe F, Nassogne MC, Roche S, Roubertie A, Sacaze E, Touati G, Broué P. Fructose-1,6-bisphosphatase deficiency causes fatty liver disease and requires long-term hepatic follow-up. J Inherit Metab Dis 2022; 45:215-222. [PMID: 34687058 DOI: 10.1002/jimd.12452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 11/06/2022]
Abstract
Liver disease, occurring during pediatric or adult age, is often of undetermined cause. Some cases are probably related to undiagnosed inherited metabolic disorders. Hepatic disorders associated with fructose-1,6-bisphosphatase deficiency, a gluconeogenesis defect, are not reported in the literature. These symptoms are mainly described during acute crises, and many reports do not mention them because hypoglycemia and hyperlactatemia are more frequently in the forefront. Herein, the liver manifestations of 18 patients affected with fructose-1,6-bisphosphatase deficiency are described and the corresponding literature is reviewed. Interestingly, all 18 patients had liver abnormalities either during follow-up (hepatomegaly [n = 8/18], elevation of transaminases [n = 6/15], bright liver [n = 7/11]) or during acute crises (hepatomegaly [n = 10/17], elevation of transaminases [n = 13/16], acute liver failure [n = 6/14], bright liver [n = 4/14]). Initial reports described cases of liver steatosis, when liver biopsy was necessary to confirm the diagnosis by an enzymatic study. There is no clear pathophysiological basis for this fatty liver disease but we postulate that endoplasmic reticulum stress and de novo lipogenesis activation could be key factors, as observed in FBP1 knockout mice. Liver steatosis may expose patients to severe long-term liver complications. As hypoglycemia becomes less frequent with age, most adult patients are no longer monitored by hepatologist. Signs of fructose-1,6-bisphosphatase deficiency may be subtle and can be missed in childhood. We suggest that fructose-1,6-bisphosphatase deficiency should be considered as an etiology of hepatic steatosis, and a liver monitoring protocol should be set up for these patients, during lifelong follow-up.
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Affiliation(s)
- Magali Gorce
- Centre de référence des maladies héréditaires du métabolisme, Unité pédiatrique de Gastro-entérologie, hépatologie, nutrition et Maladies héréditaires du métabolisme, CHU de Toulouse-Hôpital des Enfants, Toulouse, France
| | - Elise Lebigot
- APHP, CHU Bicêtre, Service de biochimie, Le Kremlin-Bicêtre, Paris, France
| | - Alina Arion
- Centre de compétence des maladies héréditaires du métabolisme, Service de pédiatrie médicale, CHU de Caen - Hôpital de la Côte de Nacre, Caen, France
| | - Anaïs Brassier
- Centre de référence des maladies héréditaires du métabolisme, Institut Imagine, Hôpital Necker, Université Paris-Descartes, Paris, France
| | - Aline Cano
- Centre de référence des maladies héréditaires du métabolisme, Service de neurologie pédiatrique, Pédiatrie spécialisée et médecine infantile, CHU de Marseille-Hôpital de la Timone, Marseille, France
| | - Pascale De Lonlay
- Centre de référence des maladies héréditaires du métabolisme, Institut Imagine, Hôpital Necker, Université Paris-Descartes, Paris, France
| | - François Feillet
- Centre de référence des maladies héréditaires du métabolisme, Service de médecine infantile, CHU Brabois Enfants, Vandœuvre-lès-Nancy, France
| | - Claire Gay
- Centre de compétence des maladies héréditaires du métabolisme, Service de Pédiatrie, CHU de Saint-Etienne-Hôpital Nord, Saint Etienne, France
| | - François Labarthe
- Centre de référence des maladies héréditaires du métabolisme, Service de Médecine pédiatrique, Pediatrics Departement, CHRU de Tours-Hôpital Clocheville, Tours, France
| | - Marie-Cécile Nassogne
- Service de neurologie pédiatrique et Centre de référence des maladies métaboliques héréditaires-Cliniques Universitaires Saint-Luc, UCLouvain, Bruxelles, Belgium
| | - Sandrine Roche
- Centre de compétence des maladies héréditaires du métabolisme, Service de pédiatrie médicale, CHU Bordeaux, hôpital Pellegrin, Bordeaux, France
| | - Agathe Roubertie
- Centre de compétence des maladies héréditaires du métabolisme, Département de neuropédiatrie, Pôle Femme Mère Enfant, CHRU de Montpellier-Hôpital Gui de Chauliac, Montpellier, France
| | - Elise Sacaze
- Centre de compétence des maladies héréditaires du métabolisme, Service de Pédiatrie, Pôle Femme-Mère-Enfant, CHRU de Brest-Hôpital Morvan, Brest, France
| | - Guy Touati
- Centre de référence des maladies héréditaires du métabolisme, Unité pédiatrique de Gastro-entérologie, hépatologie, nutrition et Maladies héréditaires du métabolisme, CHU de Toulouse-Hôpital des Enfants, Toulouse, France
| | - Pierre Broué
- Centre de référence des maladies héréditaires du métabolisme, Unité pédiatrique de Gastro-entérologie, hépatologie, nutrition et Maladies héréditaires du métabolisme, CHU de Toulouse-Hôpital des Enfants, Toulouse, France
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6
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Fawdry H, Gorrigan R, Ramachandran R, Drake WM. A novel variant of fructose‐1,6‐bisphosphatase gene identified in an adult with newly diagnosed hepatitis C. JIMD Rep 2022; 63:109-113. [PMID: 35281660 PMCID: PMC8898736 DOI: 10.1002/jmd2.12256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 11/14/2022] Open
Abstract
Hepatic fructose‐1,6‐bisphosphatase (FBPase) deficiency commonly presents with acute crises during infancy when glycogen stores are depleted. In these patients, dependence on glycogenolysis means that the duration of normoglycaemia is related to liver glycogen stores. Clinical hallmarks of FBPase deficiency include hypoglycaemia and lactic acidosis with or without ketosis. Patients commonly present with hyperventilation, vomiting, tachycardia, reduced consciousness and glucagon‐resistant hypoglycaemia. Between crises, patients are usually well with normal growth and development; however significant ingestion of fructose, sucrose or glycerol during acute crises may be fatal, hence the importance of a prompt diagnosis. We present the case of a 30‐year‐old male who presented to our tertiary centre acutely unwell, shortly following a diagnosis of hepatitis C, which we speculate may have precipitated this severe presentation. He had similar, milder episodes throughout childhood. Furthermore, a pathological homozygous sequence variant in fructose‐1,6‐bisphosphatase (FBP1) gene, previously unreported, was identified. Diagnosis in adulthood is underreported in the literature, however, represents an important, albeit rare, cause of hypoglycaemia and lactic acidosis.
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7
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Pinheiro FC, Ligabue-Braun R, Siqueira ACMD, Matuella C, Souza CFMD, Monteiro FP, Kok F, Schwartz IVD, Sperb-Ludwig F. The fructose-1,6-bisphosphatase deficiency and the p.(Lys204ArgfsTer72) variant. Genet Mol Biol 2021; 44:e20200281. [PMID: 33999094 PMCID: PMC8127874 DOI: 10.1590/1678-4685-gmb-2020-0281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 03/25/2021] [Indexed: 11/21/2022] Open
Abstract
Fructose-1,6-bisphosphatase (FBPase) deficiency is a rare inborn error of fructose metabolism caused by pathogenic variants in the FBP1 gene. As gluconeogenesis is affected, catabolic episodes can induce ketotic hypoglycemia in patients. FBP1 analysis is the most commonly used approach for the diagnosis of this disorder. Herein, a Brazilian patient is reported. The proband, a girl born to a consanguineous couple, presented with severe hypoglycemia crisis in the neonatal period. At the age 17 months, presented a new crisis accompanied by metabolic acidosis associated with a feverish episode. Genetic analysis was performed by next-generation sequencing (NGS), identifying the NM_000507.3:c.611_614del variant in homozygosis in the FBP1 gene. In silico analysis and 3D modeling were performed, suggesting that this variant is associated with a loss of sites for substrate and Mg2+ binding and for posttranslational modifications of FBPase. The c.611_614del variant is located in a repetitive region of the FBP1 gene that appears to be a hotspot for mutational events. This frameshift creates a premature termination codon in the last coding exon which escapes the nonsense-mediated decay mechanism, according to in silico analysis. This variant results in an intrinsically disordered protein with loss of substrate recognition and post-translational modification sites.
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Affiliation(s)
- Franciele Cabral Pinheiro
- Universidade Federal do Rio Grande do Sul (UFRGS), Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil.,Hospital de Clínicas de Porto Alegre (HCPA), Centro de Pesquisas Experimentais, Porto Alegre, RS, Brazil.,Universidade Federal do Pampa (UNIPAMPA), Itaqui, RS, Brazil
| | - Rodrigo Ligabue-Braun
- Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Departamento de Farmacociências, Porto Alegre, RS, Brazil
| | - Ana Cecília Menezes de Siqueira
- Instituto de Medicina Integral Professor Fernando Figueira (IMIP), Centro de Erros Inatos do Metabolismo (CETREIM), Recife, PE, Brazil
| | - Camila Matuella
- Hospital de Clínicas de Porto Alegre (HCPA), Centro de Pesquisas Experimentais, Porto Alegre, RS, Brazil
| | | | | | - Fernando Kok
- Mendelics Genomic Analysis, São Paulo, SP, Brazil.,Universidade de São Paulo, Faculdade de Medicina, Departamento de Neurologia, São Paulo, SP, Brazil
| | - Ida Vanessa Doederlein Schwartz
- Universidade Federal do Rio Grande do Sul (UFRGS), Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil.,Hospital de Clínicas de Porto Alegre (HCPA), Centro de Pesquisas Experimentais, Porto Alegre, RS, Brazil.,Hospital de Clínicas de Porto Alegre, Serviço de Genética Médica, Porto Alegre, RS, Brazil
| | - Fernanda Sperb-Ludwig
- Universidade Federal do Rio Grande do Sul (UFRGS), Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil.,Hospital de Clínicas de Porto Alegre (HCPA), Centro de Pesquisas Experimentais, Porto Alegre, RS, Brazil
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8
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Kılıç M, Kasapkara ÇS, Yılmaz DY, Özgül RK. Exon 2 deletion represents a common mutation in Turkish patients with fructose-1,6-bisphosphatase deficiency. Metab Brain Dis 2019; 34:1487-1491. [PMID: 31278438 DOI: 10.1007/s11011-019-00455-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 06/27/2019] [Indexed: 10/26/2022]
Abstract
Fructose-1,6-bisphosphatase (FBPase) deficiency is an autosomal recessive inborn error of gluconeogenesis. We aimed to investigate clinical and biochemical findings and molecular genetic data in ten Turkish patients with fructose-1,6-bisphosphatase deficiency. Ten Turkish patients who were diagnosed with fructose-1,6-biphosphatase deficiency in a single center from 2013 to 2019 were included in this study. Their clinical and laboratory data were collected retrospectively. All patients were hospitalised in intensive care unit mostly after catabolic stress conditions such as infections, starvation and rarely fructose consumption. Prognosis was good after correct diagnosis and treatment. Molecular analyses of FBP1 gene revealed a homozygous exon 2 deletion in eight patients, a novel homozygous c.910_911dupTT mutation in one patient and a homozygous IVS5 + 1G > A splicing mutation in one patient. Exon 2 deletion (previously termed exon 1) was found to be the most common mutation in Turkish fructose-1,6-biphosphatase deficiency patients.
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Affiliation(s)
- Mustafa Kılıç
- Metabolism Unit, Sami Ulus Children Hospital, Babur cad. No: 44, 06080 Altındağ, Ankara, Turkey.
| | - Çiğdem Seher Kasapkara
- Metabolism Unit, Sami Ulus Children Hospital, Babur cad. No: 44, 06080 Altındağ, Ankara, Turkey
| | - Didem Yücel Yılmaz
- Institute of Child Health, Metabolism Unit, Hacettepe University, Ankara, Turkey
| | - Rıza Köksal Özgül
- Institute of Child Health, Metabolism Unit, Hacettepe University, Ankara, Turkey
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