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He KY, Yu HP, Zou J, Chen X, Chen L, Ruan DD, Chen T, Chen Q, Zhang L, Gao MZ, Lin XF, Li H, Fang ZT, Wu J, Luo JW, Liao LS. A novel stoploss mutation CYB5R3 c.906A>G(p.*302Trpext*42) involved in the pathogenesis of hereditary methemoglobinemia. Clin Chim Acta 2024:119930. [PMID: 39154701 DOI: 10.1016/j.cca.2024.119930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2024] [Revised: 08/03/2024] [Accepted: 08/15/2024] [Indexed: 08/20/2024]
Abstract
Recessive congenital methemoglobinemia (RCM) is a hereditary autosomal disorder with an extremely low incidence rate. Here, we report a case of methemoglobinemia type I in a patient with congenital persistent cyanosis. The condition was attributed to a novel compound heterozygous mutation in CYB5R3, characterized by elevated methemoglobin levels (13.4 % of total hemoglobin) and undetectable NADH cytochrome b5 reductase (CYB5R3) activity. Whole-exome sequencing (WES) revealed two heterozygous mutations in CYB5R3: a previously reported pathogenic missense mutation c.611G>A(p.Cys204Tyr) inherited from the father, and a novel stop codon mutation c.906A>G(p.*302Trpext*42) from the mother, the latter mutation assessed as likely pathogenic according to ACMG guidelines. In cells overexpressing the CYB5R3 c.906A>G mutant construct, the CYB5R3 mRNA level was significantly lower than in cells overexpressing the wild-type (WT) CYB5R3 construct. However, there was no significant difference in protein expression levels between the mutant and WT constructs. Notably, an additional protein band of approximately 55 kDa was detected in the mutant cells. Immunofluorescence localization showed that, compared to wild-type CYB5R3, the subcellular localization of the CYB5R3 p.*302Trpext*42 mutant protein did not show significant changes and remained distributed in the endoplasmic reticulum and mitochondria. However, the c.906A>G(p.*302Trpext*42) mutation resulted in increased intracellular reactive oxygen species (ROS) levels and decreased NAD+/NADH ratio, suggesting impaired CYB5R3 function and implicating this novel mutation as likely pathogenic.
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Affiliation(s)
- Kai-Ying He
- Fujian University of Traditional Chinese Medicine, Fuzhou, China; Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Hong-Ping Yu
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Jing Zou
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Xiang Chen
- The First Clinical Medical College, Nanchang University, Nanchang 330006, China
| | - Li Chen
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Dan-Dan Ruan
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Ting Chen
- School of Medicine, Shanghai University, Shanghai 200444, China
| | - Qian Chen
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Li Zhang
- Nephrology Department, Fujian Provincial Hospital, Fuzhou, China
| | - Mei-Zhu Gao
- Nephrology Department, Fujian Provincial Hospital, Fuzhou, China
| | - Xin-Fu Lin
- Pediatrics Department, Fujian Provincial Hospital, Fuzhou, China
| | - Hong Li
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China
| | - Zhu-Ting Fang
- Clinical School of Oncology, Fujian Medical University, Fuzhou, China.
| | - Jing Wu
- Fujian University of Traditional Chinese Medicine, Fuzhou, China.
| | - Jie-Wei Luo
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China.
| | - Li-Sheng Liao
- Department of Traditional Chinese Medicine, Shengli Clinical Medical College of Fujian Medical University, Fujian Provincial Hospital, Fuzhou, China; Department of Hematology, Fujian Provincial Hospital, Fuzhou, China.
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Nicita F, Sabatini L, Alesi V, Lucignani G, Sallicandro E, Sferra A, Bertini E, Zanni G, Palumbo G. Neurological and Neuroimaging Features of CYB5R3-Related Recessive Hereditary Methemoglobinemia Type II. Brain Sci 2022; 12:brainsci12020182. [PMID: 35203946 PMCID: PMC8870218 DOI: 10.3390/brainsci12020182] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/16/2022] [Accepted: 01/24/2022] [Indexed: 02/06/2023] Open
Abstract
Recessive hereditary methemoglobinemia (RHM) due to NADH-cytochrome b5 reductase deficiency is a rare disease caused by pathogenic variants in CYB5R3. Unlike type I, in RHM type II (RHM2), the enzymatic defect affects erythrocytes and all body tissues, thus resulting in cyanosis and neurological impairment. Although the first description of RHM2 dates back to the mid-1950s, detailed clinical and neuroimaging information are available for only a few patients. Here, we describe a new patient with RHM2 that harbors an unreported homozygous 31 Kb deletion involving part of CYB5R3, and showing a peculiar neuroimaging pattern resembling a ponto-cerebellar hypoplasia-like condition. A careful review of the available literature was performed with the aim of better delineating neurological and neuroimaging as well as the genotypic spectra of this extremely rare disease.
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Affiliation(s)
- Francesco Nicita
- Unit of Neuromuscular and Neurodegenerative Disorders, Genetics and Rare Diseases Research Division, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (A.S.); (E.B.); (G.Z.)
- Correspondence: ; Tel.: +39-06-68592105
| | - Letizia Sabatini
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (L.S.); (G.P.)
- Department of Pediatrics, University of Rome Tor Vergata, 00146 Rome, Italy
| | - Viola Alesi
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children 5 Hospital and Research Institute, IRCCS, 00146 Rome, Italy; (V.A.); (E.S.)
| | - Giulia Lucignani
- Unit of Neuroradiology, Department of Radiology, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy;
| | - Ester Sallicandro
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children 5 Hospital and Research Institute, IRCCS, 00146 Rome, Italy; (V.A.); (E.S.)
| | - Antonella Sferra
- Unit of Neuromuscular and Neurodegenerative Disorders, Genetics and Rare Diseases Research Division, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (A.S.); (E.B.); (G.Z.)
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Genetics and Rare Diseases Research Division, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (A.S.); (E.B.); (G.Z.)
| | - Ginevra Zanni
- Unit of Neuromuscular and Neurodegenerative Disorders, Genetics and Rare Diseases Research Division, Department of Neurosciences, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (A.S.); (E.B.); (G.Z.)
| | - Giuseppe Palumbo
- Department of Pediatric Hemato-Oncology and Cell and Gene Therapy, Bambino Gesù Children’s Hospital, IRCCS, 00146 Rome, Italy; (L.S.); (G.P.)
- Department of Pediatrics, University of Rome Tor Vergata, 00146 Rome, Italy
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3
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AlFaris HS, Elhissi G, Chedrawi A, Al-Muhaizea MA. Beyond a routine blood gas, an easily picked but missed diagnosis of chronic Encephalopathy. Int J Pediatr Adolesc Med 2021; 8:52-54. [PMID: 33718579 PMCID: PMC7922839 DOI: 10.1016/j.ijpam.2020.01.003] [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: 10/29/2019] [Revised: 12/19/2019] [Accepted: 01/07/2020] [Indexed: 12/04/2022]
Abstract
Recessive congenital methemoglobinemia (RCM) is a rare neurological disorder caused by a deficiency in NADH-CYB5R. RCM has two main types I&II, with cyanosis being the hallmark feature in both. Type-I is a mild form, with cyanosis being the only feature. While type-II is the severe form with prominent neurological symptoms including, dystonia and spasticity. However, the cyanosis is subtle and difficult to appreciate. The cyanosis in RCM is treated with ascorbic-acid or methylene-blue. However, those treatments will not alter the neurological complication. In this paper, we report two cases of RCM type-II in Saudi siblings. They presented with cyanosis at birth; a CO-oximetry was done showing a high level of methemoglobin and a trail of methylene blue was used. The siblings were followed up and showed signs of developmental delay, hypotonia, exaggerated reflex, and seizure. A genetic analysis was requested, which showed missense mutation (c.274 C > T), leading to amino acid substitution; p. Arg92Trp.
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Affiliation(s)
- Haya S AlFaris
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Division of Pediatric Neurology, Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Ghasan Elhissi
- Department of Pediatrics, King Khaled University Hospital, King Saud University, Riyadh, Saudi Arabia
| | - Aziza Chedrawi
- Division of Pediatric Neurology, Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Mohammad A Al-Muhaizea
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.,Division of Pediatric Neurology, Department of Neurosciences, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
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Gupta V, Kulkarni A, Warang P, Devendra R, Chiddarwar A, Kedar P. Mutation update: Variants of the CYB5R3 gene in recessive congenital methemoglobinemia. Hum Mutat 2020; 41:737-748. [PMID: 31898843 DOI: 10.1002/humu.23973] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 12/05/2019] [Accepted: 12/26/2019] [Indexed: 11/07/2022]
Abstract
NADH-cytochrome b5 reductase 3 deficiency is an important genetic cause of recessive congenital methemoglobinemia (RCM) and occurs worldwide in autosomal recessive inheritance. In this Mutation Update, we provide a comprehensive review of all the pathogenic mutations and their molecular pathology in RCM along with the molecular basis of RCM in 21 new patients from the Indian population, including four novel variants: c.103A>C (p.Thr35Pro), c.190C>G (p.Leu64Val), c.310G>T (p.Gly104Cys), and c.352C>T (p.His118Tyr). In this update, over 78 different variants have been described for RCM globally. Molecular modeling of all the variants reported in CYB5R3 justifies association with the varying severity of the disease. The majority of the mutations associated with the severe form with a neurological disorder (RCM Type 2) were associated with the FAD-binding domain of the protein while the rest were located in another domain of the protein (RCM Type 1).
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Affiliation(s)
- Vinod Gupta
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Anuja Kulkarni
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Prashant Warang
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Rati Devendra
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Ashish Chiddarwar
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
| | - Prabhakar Kedar
- Department of Haematogenetics, ICMR-National Institute of Immunohaematology, King Edward Memorial Hospital Campus, Mumbai, India
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Franco R, Navarro G, Martínez-Pinilla E. Antioxidant Defense Mechanisms in Erythrocytes and in the Central Nervous System. Antioxidants (Basel) 2019; 8:antiox8020046. [PMID: 30781629 PMCID: PMC6406447 DOI: 10.3390/antiox8020046] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 02/09/2019] [Accepted: 02/13/2019] [Indexed: 12/16/2022] Open
Abstract
Differential antioxidant action is found upon comparison of organ/tissue systems in the human body. In erythrocytes (red blood cells), which transport oxygen and carbon dioxide through the circulatory system, the most important issue is to keep hemoglobin in a functional state that requires maintaining the haem group in ferrous (Fe2+) state. Conversion of oxidized Fe3+ back into Fe2+ in hemoglobin needs a special mechanism involving a tripeptide glutathione, glucose-6-phosphate dehydrogenase, and glucose and NADPH as suppliers of reducing power. Fava beans are probably a good resource to make the detox innate system more robust as the pro-oxidant molecules in this food likely induce the upregulation of members of such mechanisms. The central nervous system consumes more oxygen than the majority of human tissues, i.e., 20% of the body's total oxygen consumption and, therefore, it is exposed to a high level of oxidative stress. This fact, together with the progressive age-related decline in the efficiency of the antioxidant defense system, leads to neuronal death and disease. The innate mechanism operating in the central nervous system is not well known and seems different to that of the erythrocytes. The strategies of antioxidant intervention in brain will be reviewed here.
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Affiliation(s)
- Rafael Franco
- Molecular Neurobiology Laboratory, Department of Biochemistry and Molecular Biomedicine, Biology School, University of Barcelona, Barcelona 08028, Spain.
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain.
| | - Gemma Navarro
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid 28031, Spain.
- Department of Biochemistry and Physiology, Pharmacy and Food Science School, University of Barcelona, Barcelona 08028, Spain.
| | - Eva Martínez-Pinilla
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias 33006, Spain.
- Instituto de Neurociencias del Principado de Asturias (INEUROPA), Asturias 33006, Spain.
- Instituto de Salud del Principado de Asturias (ISPA), Asturias 33006, Spain.
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6
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Nicolas-Jilwan M. Recessive congenital methemoglobinemia type II: Hypoplastic basal ganglia in two siblings with a novel mutation of the cytochrome b5 reductase gene. Neuroradiol J 2019; 32:143-147. [PMID: 30614390 DOI: 10.1177/1971400918822153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Recessive congenital methemoglobinemia type II is a very rare autosomal recessive hematologic disorder due to NADH-cytochrome b5 reductase deficiency, usually caused by full-stop mutations or deletions. This disease classically presents with mild neonatal cyanosis, early onset severe progressive developmental delay, movement disorders, and progressive microcephaly. We report two siblings with recessive congenital methemoglobinemia type II whose evaluation revealed a novel p.Arg92Trp missense mutation of the CYB5R3 gene and a peculiar imaging finding of basal ganglia hypoplasia. Brain magnetic resonance imaging was performed at age 10 months in the older sibling and at age three months in the younger sibling. It revealed similar findings of bilateral small size of the lentiform and caudate nuclei and reduced frontotemporal brain volume. Our patient cases highlight that basal ganglia hypoplasia is an interesting clue to the very rare and frequently unsuspected diagnosis of recessive congenital methemoglobinemia type II, that may explain the associated movement disorders. The novel missense mutation is one of very few identified missense mutations known to cause severe type II recessive congenital methemoglobinemia.
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Affiliation(s)
- Manal Nicolas-Jilwan
- Department of Radiology, King Faisal Specialist Hospital and Research Centre, Saudi Arabia
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7
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Kedar PS, Gupta V, Warang P, Chiddarwar A, Madkaikar M. Novel mutation (R192C) in CYB5R3 gene causing NADH-cytochrome b5 reductase deficiency in eight Indian patients associated with autosomal recessive congenital methemoglobinemia type-I. ACTA ACUST UNITED AC 2018; 23:567-573. [PMID: 29482478 DOI: 10.1080/10245332.2018.1444920] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To investigate the cause of recessive congenital methemoglobinemia (RCM) in Indian families and to identify molecular defect associated with RCM. METHODS Eight cases of RCM have been addressed to our laboratory in order to investigate the cause of cyanosis associated with genetic disorders. NADH-cytochrome b5 reductase (cytb5r) enzyme activities were measured by standard methods, and molecular analysis was performed by polymerase chain reaction (PCR) followed by DNA sequencing. The interpretation of mutation effect and the molecular modeling were performed by using specific software DEEP VIEW SWISS-PDB VIEWER and Pymol molecular graphics program. RESULTS AND DISCUSSION Eight index cases from four unrelated families were referred for the cause of cyanosis. All patients showed mild to moderate cyanosis without mental retardation or any neurologic abnormalities. The methemoglobin levels were in the range of 11.5-22.41% with 50-70% reduction in CYTB5R activity. Spectroscopic analysis of the hemolysate showed normal peaks suggesting the absence of Hb-M. Molecular characterization showed a novel homozygous mutation p.Arg192Cys in CYB5R3 gene is an evolutionarily conserved position located in exon 7 in all eight index cases. The substitution of Cys is located on the interface of two domains of NADH-binding domain and is close proximity to the adenosine moiety would preclude the reciprocal ionic interaction (salt bridge) between Arg192 and Ile97 and may influence binding of the NADH coenzyme is hypothesized to cause disruption of hydrogen bonding and instability. Our study indicated that novel homozygous mutation p.Arg192Cys in CYB5R3 gene present in eight cases and the possibility of high prevalence of heterozygous in Indian population causing Type I RCM.
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Affiliation(s)
- Prabhakar S Kedar
- a National Institute of Immunohematology , Indian Council of Medical Research , Mumbai , India
| | - Vinod Gupta
- a National Institute of Immunohematology , Indian Council of Medical Research , Mumbai , India
| | - Prashant Warang
- a National Institute of Immunohematology , Indian Council of Medical Research , Mumbai , India
| | - Ashish Chiddarwar
- a National Institute of Immunohematology , Indian Council of Medical Research , Mumbai , India
| | - Manisha Madkaikar
- a National Institute of Immunohematology , Indian Council of Medical Research , Mumbai , India
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Mannino EA, Pluim T, Wessler J, Cho MT, Juusola J, Schrier Vergano SA. Congenital methemoglobinemia type II in a 5-year-old boy. Clin Case Rep 2018; 6:170-178. [PMID: 29375859 PMCID: PMC5771927 DOI: 10.1002/ccr3.1310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/24/2017] [Accepted: 11/13/2017] [Indexed: 11/26/2022] Open
Abstract
Congenital Methemoglobinemia is a rare neurologic condition which can mimic other diseases such as epilepsy syndromes and leukodystrophies. The responsible gene, CYB5R3, is not typically included on commonly order neurologic and epilepsy panels. We recommend that laboratories include this gene on these tests which often precede larger-scale genetic studies.
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Affiliation(s)
| | - Thomas Pluim
- Division of Pediatric Critical Care MedicineNaval Medical Center PortsmouthPortsmouthVirginia
| | - Jacob Wessler
- Division of Pediatric Hematology/OncologyNaval Medical Center PortsmouthPortsmouthVirginia
| | | | | | - Samantha A. Schrier Vergano
- Division of Medical Genetics and MetabolismChildren's Hospital of The King's DaughtersNorfolkVirginia
- Department of PediatricsEastern Virginia Medical SchoolNorfolkVirginia
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Kedar P, Desai A, Warang P, Colah R. A microplate reader-based method to quantify NADH-cytochrome b5 reductase activity for diagnosis of recessive congenital methaemoglobinemia. ACTA ACUST UNITED AC 2016; 22:252-257. [PMID: 27863456 DOI: 10.1080/10245332.2016.1252873] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVES Congenital methemoglobinemia due to NADH-cytochrome b5 reductase 3 (CYB5R3) deficiencies is an autosomal recessive disorder that occurs sporadically worldwide, A sensitive, accurate, and rapid analysis of NADH-CYB5R enzyme concentrations is necessary for the diagnosis of RCM. Here we present an alternative microplate method that is based on a standard 96-well microplate format and microplate reader that simplify the quantification of NADH-CYB5R activity. METHODS TECAN (Infinite 200 PRO series) microplate reader with Tecan's proven Magellan™ software measured the NADH-CYB5R enzyme activity in 250 normal controls and previously diagnosed 25 cases of RCM due to NADH-CYB5R deficiency in the Indian population using 96-well microplates using 200 μl of total reaction mixture and also compared with standard spectrophotometric assay. We have also studied stability of the hemolysate stored at 4 and -20°C temperature. RESULTS AND DISCUSSION Enzyme activity in all 25 samples ranged from 6.09 to 10.07 IU/g Hb (mean ± SD: 8.08 ± 1.99 IU/g Hb) where as normal control ranged (n = 250) between 13.42 and 21.58 IU/g Hb) (mean ± SD: 17.5 ± 4.08 IU/g of Hb). Data obtained from the microplate reader were compared with standard spectrophotometer method and found 100% concordance using both methods. Microplate method allows differentiating between normal, deficient and intermediate enzyme activity. It was observed that samples had significant loss of activity when stored at 4°C and retained stable activity at -20°C for 1 week time. CONCLUSION Our new method, incorporating a whole process of enzyme assay into a microplate format is readily applicable and allows rapid monitoring of enzyme assay. It is readily applicable to quantitative assay on pediatric sample as well as large number of samples for population screening.
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Affiliation(s)
- Prabhakar Kedar
- a National Institute of Immunohematology (Indian Council of Medical Research) , Mumbai , India
| | - Anand Desai
- a National Institute of Immunohematology (Indian Council of Medical Research) , Mumbai , India
| | - Prashant Warang
- a National Institute of Immunohematology (Indian Council of Medical Research) , Mumbai , India
| | - Roshan Colah
- a National Institute of Immunohematology (Indian Council of Medical Research) , Mumbai , India
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10
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Ozcelik AA, Perk P, Dai A. Congenital methemoglobinemia type 2 and cerebellar atrophy/hypoplasia. Acta Neurol Belg 2016; 116:217-9. [PMID: 26133947 DOI: 10.1007/s13760-015-0502-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 06/13/2015] [Indexed: 12/01/2022]
Affiliation(s)
- Ayse Aysima Ozcelik
- Division of Pediatric Neurology, Faculty of Medicine, Gaziantep University, 3th floor, Şehitkamil, 27310, Gaziantep, Turkey.
| | - Peren Perk
- Division of Pediatric Neurology, Faculty of Medicine, Gaziantep University, 3th floor, Şehitkamil, 27310, Gaziantep, Turkey
| | - Alper Dai
- Division of Pediatric Neurology, Faculty of Medicine, Gaziantep University, 3th floor, Şehitkamil, 27310, Gaziantep, Turkey
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11
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High expression of cytochrome b 5 reductase isoform 3/cytochrome b 5 system in the cerebellum and pyramidal neurons of adult rat brain. Brain Struct Funct 2015; 221:2147-62. [DOI: 10.1007/s00429-015-1036-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/27/2015] [Indexed: 10/23/2022]
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12
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Rawa K, Chelmecka-Hanusiewicz L, Plochocka D, Pawinska-Wasikowska K, Balwierz W, Burzynska B. Characterization of a novel mutation in the NADH-cytochrome b5 reductase gene responsible for rare hereditary methaemoglobinaemia type I. Acta Haematol 2013; 130:122-5. [PMID: 23594618 DOI: 10.1159/000347041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 12/30/2012] [Indexed: 11/19/2022]
Affiliation(s)
- Katarzyna Rawa
- Department of Paediatrics, Haematology and Oncology, Medical University of Warsaw, Warsaw, Poland
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13
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Galeeva NM, Nenasheva SA, Kleymenova IS, Polyakov AV. Novel large deletion c.22-1320_633+1224del in the CYB5R3 gene from patients with hereditary methemoglobinemia. RUSS J GENET+ 2012. [DOI: 10.1134/s1022795412110038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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14
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Elahian F, Sepehrizadeh Z, Moghimi B, Mirzaei SA. Human cytochrome b5 reductase: structure, function, and potential applications. Crit Rev Biotechnol 2012; 34:134-43. [PMID: 23113554 DOI: 10.3109/07388551.2012.732031] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cytochrome b5 reductase is a flavoprotein that is produced as two different isoforms that have different localizations. The amphipathic microsomal isoform, found in all cell types with the exception of erythrocytes, consists of one hydrophobic membrane-anchoring domain and a larger hydrophilic flavin catalytic domain. The soluble cytochrome b5 reductase isoform, found in human erythrocytes, is a truncated protein that is encoded by an alternative transcript and consists of the larger domain only. Cytochrome b5 reductase is involved in the transfer of reducing equivalents from the physiological electron donor, NADH, via an FAD domain to the small molecules of cytochrome b5. This protein has received much attention from researchers due to its involvement in many oxidation and reduction reactions, such as the reduction of methemoglobin to hemoglobin. Autosomal cytochrome b5 reductase gene deficiency manifests with the accumulation of oxidized Fe+3 and recessive congenital methemoglobinemia in humans. In this article, we provide a comprehensive overview of the structure and function of cytochrome b5 reductase from different eukaryotic sources and its potential use in the food industry, biosensor, and diagnostic areas.
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Affiliation(s)
- Fatemeh Elahian
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Zanjan University of Medical Sciences , Iran and
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15
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Fusco C, Soncini G, Frattini D, Della Giustina E, Vercellati C, Fermo E, Bianchi P. Cerebellar atrophy in a child with hereditary methemoglobinemia type II. Brain Dev 2011; 33:357-60. [PMID: 20650578 DOI: 10.1016/j.braindev.2010.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 06/14/2010] [Accepted: 06/18/2010] [Indexed: 12/21/2022]
Abstract
We report the first case of a child with recessive hereditary methemoglobinemia type II with demonstrated cerebellar atrophy. This very rare blood disorder results in mild cyanosis, profound mental and motor impairment, and movement disorders in infancy and childhood. We suggest that children with unexplained severe encephalopathy and cerebellar atrophy should also be tested for hereditary methemoglobinemia type II.
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Affiliation(s)
- Carlo Fusco
- Child Neurology Unit, Arcispedale Santa Maria Nuova, Viale Risorgimento 80, Reggio Emilia, Italy.
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Fermo E, Bianchi P, Vercellati C, Marcello AP, Garatti M, Marangoni O, Barcellini W, Zanella A. Recessive hereditary methemoglobinemia: two novel mutations in the NADH-cytochrome b5 reductase gene. Blood Cells Mol Dis 2008; 41:50-5. [PMID: 18343696 DOI: 10.1016/j.bcmd.2008.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 02/06/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022]
Abstract
We report the clinical and molecular characteristics of 6 new patients with recessive hereditary methemoglobinemia due to cytochrome b5 reductase deficiency. One patient was affected by Type-II disease with cyanosis and severe progressive neurological dysfunction, whereas the others displayed the benign Type-I phenotype. Methemoglobin levels ranged from 12.1% to 26.2% and cytochrome b5 reductase activity from 0 to 10% of normal. Eight different mutations were detected among the twelve mutated alleles identified, one splicing mutation, two stop codon, and five missense. Two mutations c. 82 C>T(Gln27STOP) and c. 136 C>T(Arg45Trp) are new. Prenatal diagnosis was performed in the family with Type-II disease.
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Affiliation(s)
- Elisa Fermo
- U.O. Ematologia 2, Fondazione IRCCS Ospedale Maggiore, Mangiagalli e Regina Elena, Via F. Sforza, 35, 20122 Milano, Italy
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17
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Percy MJ, Crowley LJ, Boudreaux J, Barber MJ. Expression of a novel P275L variant of NADH:cytochrome b5 reductase gives functional insight into the conserved motif important for pyridine nucleotide binding. Arch Biochem Biophys 2006; 447:59-67. [PMID: 16469290 DOI: 10.1016/j.abb.2005.12.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2005] [Revised: 12/21/2005] [Accepted: 12/22/2005] [Indexed: 10/25/2022]
Abstract
The clinical disorder of recessive congenital methemoglobinemia (RCM, OMIN 250800) is associated with mutations in NADH:cytochrome b5 reductase (cb5r) and manifests as cyanosis from birth. Screening a cyanotic infant indicated elevated methemoglobin levels and decreased cb5r activity suggesting RCM. Sequencing the DIA1 gene encoding cb5r revealed a novel mutation, C27161T (NCBI accession number: NT_011520), resulting in replacement of proline at amino acid 275 with leucine (P275L). To understand how this mutation would affect cb5r's function, the P275L variant was expressed in a heterologous expression system and spectroscopic, thermodynamic, and thermostability studies were performed. The leucine substitution at residue 275 was found to significantly decrease the affinity towards the physiological reducing substrate, NADH, without affecting the activity of the P275L variant. From the rat model, residue 275 is predicted to be part of a conserved "CGPPPM" motif important for the binding and correct positioning of the NADH reducing substrate. Thus P275 influences the interaction with NADH which was confirmed by the change in affinity towards the physiological reducing substrate.
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Affiliation(s)
- M J Percy
- Department of Hematology, Floor C, Tower Block, Belfast City Hospital, Lisburn Road, Belfast BT9 7AB, Northern Ireland, UK.
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Gokalp S, Unuvar E, Oguz F, Kilic A, Sidal M. A case with quadriparetic cerebral palsy and cyanosis: congenital methemoglobinemia. Pediatr Neurol 2005; 33:131-3. [PMID: 16087059 DOI: 10.1016/j.pediatrneurol.2005.02.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2004] [Revised: 10/26/2004] [Accepted: 02/05/2005] [Indexed: 11/21/2022]
Abstract
The recessive form of congenital methemoglobinemia, caused by a defect of nicotinamide adenine dinucleotide-cytb5 reductase enzyme (cytb5r), is a rare disorder clinically presenting with cyanosis. Two different forms of recessive congenital methemoglobinemia have been described: In type I, cyanosis is the only major symptom and enzyme deficiency is restricted to erythrocytes. In type II, observed in 10-15% of all patients, enzyme deficiency occurs in the entire body and cyanosis is associated with severe, progressive neurologic impairment. This report presents a 10-year-old female with recessive congenital methemoglobinemia type II. She was admitted with quadriparetic cerebral palsy, mental retardation, convulsions, swallowing difficulty, and cyanosis. Etiology of cyanosis was not clarified exactly but was readily but erroneously attributed to uncontrolled, repetitive convulsions and aspiration of excessive oral secretions. Her methemoglobin level was measured as 51%, and a diagnosis of congenital methemoglobinemia was established. Oral ascorbic acid 500 mg/day was initiated. She responded well to therapy. Interestingly, neurologic deficits improved after ascorbic acid treatment. In conclusion, cyanosis and repetitive convulsions associated with neurologic deficits may be explained by congenital methemoglobinemia, a potentially treatable condition.
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Affiliation(s)
- Selman Gokalp
- Department of Pediatrics, Istanbul Medical Faculty, Istanbul, Turkey
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19
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Abstract
Methaemoglobinaemia arises from the production of non-functional haemoglobin containing oxidised Fe(3+) which results in reduced oxygen supply to the tissues and manifests as cyanosis in the patient. It can develop by three distinct mechanisms: genetic mutation resulting in the presence of abnormal haemoglobin, a deficiency of methaemoglobin reductase enzyme and toxin-induced oxidation of haemoglobin. The normal haemoglobin fold forms a pocket to bind the haem and stabilise its complex with molecular oxygen, simultaneously preventing spontaneous oxidation of the Fe(2+) ion chelated by the haem pyrroles and the globin histidines. In the abnormal, M forms of haemoglobin (Hb Ms) amino acid substitution in or near the haem pocket creates a propensity to form methaemoglobin instead of oxyhaemoglobin in the presence of molecular oxygen. Normally, haemoglobin continually oxidises but significant accumulation of methaemoglobin is prevented by the action of a group of methaemoglobin reductase enzymes. In the autosomal recessive form of methaemoglobinaemia there is a deficiency of one of these reductase enzymes thereby allowing accumulation of oxidised Fe(3+) in methaemoglobin. Oxidising drugs and other toxic chemicals may greatly enhance the normal spontaneous rate of methaemoglobin production and if levels exceed 70% of total haemoglobin, vascular collapse occurs resulting in coma and death. Under these conditions, if the source of toxicity can be eliminated methaemoglobin levels will return to normal. Disorders of oxidised haemoglobin are relatively easily diagnosed and in most cases, except for the presence of congenitally defective haemoglobin M, can be treated successfully.
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Affiliation(s)
- Melanie J Percy
- Department of Haematology, Belfast City Hospital, Tower Block, Lisburn Road, Belfast BT9 7AB, N. Ireland, UK
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Yilmaz D, Cogulu O, Ozkinay F, Kavakli K, Roos D. A novel mutation in theDIA1 gene in a patient with methemoglobinemia type II. Am J Med Genet A 2005; 133A:101-2. [PMID: 15744830 DOI: 10.1002/ajmg.a.30467] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Joyner DE, Wade ML, Szabo A, Bastar J, Coffin CM, Albritton KH, Bernard PS, Randall RL. Discriminate gene lists derived from cDNA microarray profiles of limited samples permit distinguishing mesenchymal neoplasia ex vivo. J Cancer Res Clin Oncol 2004; 131:137-46. [PMID: 15614524 DOI: 10.1007/s00432-004-0640-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2004] [Accepted: 10/08/2004] [Indexed: 10/26/2022]
Abstract
BACKGROUND Mesenchymal neoplasia comprises a heterogeneous group of tumors with over 200 benign neoplasms and 100 sarcomas. Currently, tumors are classified using histologic and immunocytologic characteristics, with diagnostic error rates reported as high as 40% of cases. As a feasibility study, our goal was to generate a preliminary discriminatory gene list for selected mesenchymal tumors, including sarcomas. This technique may enable an eventual molecular classification schema based on expression profiles that can complement current clinical and pathologic diagnostic procedures in mesenchymal tumors. METHODS cDNA microarray analyses were preformed on connective tissue tumors obtained at time of surgical resection or biopsy. Messenger RNA (mRNA) from four general tumor classes was competitively hybridized against a human dermal fibroblast cell line comparator and the resulting gene expression profiles processed by ANOVA and linear discriminate analysis. RESULTS The tissue classification involved 18 patients with malignant peripheral nerve sheath tumors, giant cell containing tumors, benign spindle cell lesions, or Ewing's family of tumors. Lymph nodes from two patients served comparative purposes. Twenty-five differentially regulated genes considered most variable among the five tissue classes were identified. The tissues were segregated into five classes by linear discriminate analysis. CONCLUSIONS Linear discriminate analysis of cDNA gene expression profiles partitioned mesenchymal tumor classes, even when constrained by limited sample sizes.
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MESH Headings
- Analysis of Variance
- Carcinoma/diagnosis
- Carcinoma/genetics
- Carcinoma, Giant Cell/diagnosis
- Carcinoma, Giant Cell/genetics
- Cell Line
- DNA Fingerprinting
- DNA, Neoplasm/analysis
- Feasibility Studies
- Fibroblasts
- Gene Expression Regulation, Neoplastic
- Humans
- Linear Models
- Mesenchymoma/diagnosis
- Mesenchymoma/genetics
- Neoplasms, Connective Tissue/diagnosis
- Neoplasms, Connective Tissue/genetics
- Nerve Sheath Neoplasms/diagnosis
- Nerve Sheath Neoplasms/genetics
- Oligonucleotide Array Sequence Analysis
- RNA, Messenger/analysis
- RNA, Neoplasm/analysis
- Sarcoma, Ewing/diagnosis
- Sarcoma, Ewing/genetics
- Skin/cytology
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Affiliation(s)
- David E Joyner
- SAR Lab, Sarcoma Services, Department of Orthopedics, Huntsman Cancer Institute & Primary Children's Medical Center, University of Utah, Salt Lake City, UT 84112, USA
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Davis CA, Crowley LJ, Barber MJ. Cytochrome b5 reductase: the roles of the recessive congenital methemoglobinemia mutants P144L, L148P, and R159*. Arch Biochem Biophys 2004; 431:233-44. [PMID: 15488472 DOI: 10.1016/j.abb.2004.08.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Revised: 08/06/2004] [Indexed: 10/26/2022]
Abstract
Recessive congenital methemoglobinemia (RCM, OMIM 250800) arises from defects in either the erythrocytic or microsomal forms of the flavoprotein, cytochrome b5 reductase (cb5r) and was the first disease to be directly associated with a specific enzyme deficiency. Of the 33 verified mutations in cb5r that give rise to either the type I (erythrocytic) or type II (generalized) forms of RCM, three of the mutations, corresponding to P144L, L148P, and R159*, are located in a segment of the primary sequence composed of residues G143 to V171 which serves as a "hinge" or "linker" region between the FAD- and NADH-binding lobes of the protein. With the exception of R159*, which produces a truncated non-functional cb5r resulting in type II RCM, the type I methemoglobinemias resulting from the P144L or L148P mutations have been proposed to be due to decreased enzyme stability. Utilizing a recombinant form of the rat cb5r enzyme, we have generated the P144L, L148P, and P144L/L148P mutants, purified the resulting proteins to homogeneity and characterized their spectroscopic, kinetic, and thermodynamic properties. The three mutant proteins retained full complements of FAD with the P144L and L148P variants being spectroscopically indistinguishable from wild-type cb5r. In contrast, kinetic analyses revealed that the P144L, L148P, and P144L/L148P variants retained only 28, 31, and 8% of wild-type NADH:cytochrome b5 reductase activity, respectively, together with significant alterations in affinity for both NADH and NAD+. In addition, FAD oxidation-reduction potentials were 32, 19, and 65 mV more positive for the mutants than the corresponding FAD/FADH2 couple in native cb5r (E0'=-272 mV). Thermal and proteolytic stability measurements indicated that all three mutants were less stable than the wild-type protein while differential spectroscopy indicated altered pyridine nucleotide binding in all three variants. These results demonstrate that the "hinge" region is important in maintaining the correct orientation of the flavin- and pyridine nucleotide-binding lobes within the protein for efficient electron transfer and that the P144L and L148P mutations disrupt the normal registration of the FAD- and NADH-binding lobes resulting in altered affinities for both the physiological reducing substrate, NADH and its product, NAD+.
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Affiliation(s)
- C Ainsley Davis
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Florida, Tampa, FL 33612, USA
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Davis CA, Barber MJ. Cytochrome b5 oxidoreductase: expression and characterization of the original familial ideopathic methemoglobinemia mutations E255- and G291D. Arch Biochem Biophys 2004; 425:123-32. [PMID: 15111120 DOI: 10.1016/j.abb.2003.12.041] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2003] [Revised: 12/08/2003] [Indexed: 10/26/2022]
Abstract
NADH:cytochrome b5 oxidoreductase catalyzes the transfer of reducing equivalents from the physiological electron donor, NADH, to two molecules of cytochrome b5. Utilizing a heterologous expression system for the soluble, catalytic domain of the rat microsomal enzyme, we have produced two mutants, corresponding to E255- and G291D. These mutants correspond to the two specific mutations that were identified over a half century later following diagnosis of the original cases of type I recessive congenital methemoglobinemia (RCM). We have purified both the E255- and G291D variants to homogeneity to determine the molecular basis for type I RCM in these individuals. Both the E255- and G291D variants retained a full complement of FAD and exhibited absorption and CD spectroscopic properties comparable to those of the wild-type protein. Oxidation-reduction potentiometric titrations yielded standard midpoint potentials (E0') for the FAD/FADH2 couple of -271 and -273 mV for the E255- and G291D variants, respectively, which were comparable to the value of -268 mV obtained for the wild-type protein and confirmed that the redox potential of the flavin was unaffected by either mutation. Thermal and proteolytic stability studies revealed that while the G291D variant exhibited stability comparable to that of wild-type, the E255- variant was markedly less stable, indicative of an altered conformation. Initial-rate kinetic studies revealed that both mutants had decreased catalytic activity (kcat), with the E255- and G291D variants retaining approximately 38 and 58% of wild-type activity, respectively. However, the affinity for NADH (KmNADH) was decreased approximately 100-fold for E255- compared to only approximately 1.3-fold for G291D, results supported by the spectroscopic binding constant (Ks) obtained for G291D. These results indicate that the properties of both the E255- and G291D cytochrome b5 oxidoreductase mutants are similar to those of other variants that have been identified as resulting in the type I form of RCM.
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Affiliation(s)
- C Ainsley Davis
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Florida, Tampa, Florida 33612, USA
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Bewley MC, Davis CA, Marohnic CC, Taormina D, Barber MJ. The structure of the S127P mutant of cytochrome b5 reductase that causes methemoglobinemia shows the AMP moiety of the flavin occupying the substrate binding site. Biochemistry 2004; 42:13145-51. [PMID: 14609324 DOI: 10.1021/bi034915c] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methemoglobinemia, the first hereditary disease to be identified that involved an enzyme deficiency, has been ascribed to mutations in the enzyme cytochrome b(5) reductase. A variety of defects in either the erythrocytic or microsomal forms of the enzyme have been identified that give rise to the type I or type II variant of the disease, respectively. The positions of the methemoglobinemia-causing mutations are scattered throughout the protein sequence, but the majority of the nontruncated mutants that produce type II symptoms occur close to the flavin adenine dinucleotide (FAD) cofactor binding site. While X-ray structures have been determined for the soluble, flavin-containing diaphorase domains of the rat and pig enzymes, no X-ray or NMR structure has been described for the human enzyme or any of the methemoglobinemia variants. S127P, a mutant that causes type II methemoglobinemia, was the first to be positively identified and have its spectroscopic and kinetic properties characterized that revealed altered nicotinamide adenine dinucleotide hydride (NADH) substrate binding behavior. To understand these changes at a structural level, we have determined the structure of the S127P mutant of rat cytochrome b(5) reductase to 1.8 A resolution, providing the first structural snapshot of a cytochrome b(5) reductase mutant that causes methemoglobinemia. The high-resolution structure revealed that the adenosine diphosphate (ADP) moiety of the FAD prosthetic group is displaced into the corresponding ADP binding site of the physiological substrate, NADH, thus acting as a substrate inhibitor which is consistent with both the spectroscopic and kinetic data.
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Affiliation(s)
- Maria C Bewley
- Biology Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
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25
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Grabowska D, Plochocka D, Jablonska-Skwiecinska E, Chelstowska A, Lewandowska I, Staniszewska K, Majewska Z, Witos I, Burzynska B. Compound heterozygosity of two missense mutations in the NADH-cytochrome b5 reductase gene of a Polish patient with type I recessive congenital methaemoglobinaemia. Eur J Haematol 2003; 70:404-9. [PMID: 12756024 DOI: 10.1034/j.1600-0609.2003.00070.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
A case of type I methaemoglobinaemia observed in a Polish subject with compound heterozygosity for two mutations in the reduced nicotinamide adenine dinucleotide (NADH) cytochrome b5 reductase (b5R) gene is described. One is a novel mutation 647T-->C which leads to substitution of isoleucine by threonine at position 215 (I215T). This maternal mutation was found in several family members. A previously known mutation, 757G-->A, leads to the replacement of valine by methionine at position 252 (V252M). The latter mutation was found also in the father and one of the two brothers. The effects of these mutations were analysed on a model of the human b5R protein obtained by homology modelling. Although both amino acid substitutions are located in the NADH-binding domain, the whole protein structure, especially the region between the flavin adenine dinucleotide and NADH-binding domains, is disturbed. The structural changes in the I215T mutant are less prominent than those in the V252M mutant. We presume that the 647T-->C mutation is a type I mutation, however, it has not been observed in the homozygous state.
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Affiliation(s)
- Dorota Grabowska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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Percy MJ, Gillespie MJS, Savage G, Hughes AE, McMullin MF, Lappin TRJ. Familial idiopathic methemoglobinemia revisited: original cases reveal 2 novel mutations in NADH-cytochrome b5 reductase. Blood 2002; 100:3447-9. [PMID: 12393396 DOI: 10.1182/blood-2002-05-1405] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In 1943, the first description of familial idiopathic methemoglobinemia in the United Kingdom was reported in 2 members of one family. Five years later, Quentin Gibson (then of Queen's University, Belfast, Ireland) correctly identified the pathway involved in the reduction of methemoglobin in the family, thereby describing the first hereditary trait involving a specific enzyme deficiency. Recessive congenital methemoglobinemia (RCM) is caused by a deficiency of reduced nicotinamide adenine dinucleotide (NADH)-cytochrome b5 reductase. One of the original propositi with the type 1 disorder has now been traced. He was found to be a compound heterozygote harboring 2 previously undescribed mutations in exon 9, a point mutation Gly873Ala predicting a Gly291Asp substitution, and a 3-bp in-frame deletion of codon 255 (GAG), predicting loss of glutamic acid. A brother and a surviving sister are heterozygous; each bears one of the mutations. Thirty-three different mutations have now been recorded for RCM. The original authors' optimism that RCM would provide material for future genetic studies has been amply justified.
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Affiliation(s)
- Melanie J Percy
- Department of Haematology, Belfast City Hospital, Northern Ireland.
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