1
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Yang X, Tao Y, Xu Y, Cai W, Shao Q. SLC35A2 expression drives breast cancer progression via ERK pathway activation. FEBS J 2024; 291:1483-1505. [PMID: 38143314 DOI: 10.1111/febs.17044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 10/21/2023] [Accepted: 12/22/2023] [Indexed: 12/26/2023]
Abstract
Alterations in glycosylation are associated with breast tumor formation and progression. Nevertheless, the specific functions and mechanisms of the human major UDP-galactose transporter-encoding gene solute carrier family 35 member A2 (SLC35A2) in breast invasive carcinoma (BRCA) have not been fully determined. Here, we report that SLC35A2 promotes BRCA progression by activating extracellular signal regulated kinase (ERK). SLC35A2 expression and prognosis-predictive significance in pan-cancer were evaluated using public databases. The upstream non-coding RNAs (ncRNAs) of SLC35A2 were analyzed, and their expression and regulations were validated in breast tissues and cell lines by a quantitative PCR and dual-luciferase assays. We used bioinformatic tools to assess the link between SLC35A2 expression and immune infiltration and performed immunohistochemistry for validation. Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine, transwell, flow cytometer and western blotting were used to assess the proliferation, motility, cell cycle and apoptosis of BRCA cells in vitro. The xenograft models were constructed to assess the effect of SLC35A2 on BRCA tumor growth in vivo. The results indicated that SLC35A2 expression was upregulated and linked to an unfavorable prognosis in BRCA. The most likely upstream ncRNA-associated pathway of SLC35A2 in BRCA was the AC074117.1/hsa-let-7b-5p axis. SLC35A2 expression had positive correlations with the presence of Th2 cells, regulatory T cells and immune checkpoints. Knockdown of SLC35A2 could reduce BRCA cell proliferation, motility, and cause G2/M arrest and cell apoptosis via ERK signaling. Moreover, ERK activation can rescue the inhibitory effects of knockdown SLC35A2 in BRCA. In conclusion, AC074117.1/hsa-let-7b-5p axis-mediated high expression of SLC35A2 acts as a tumor promoter in BRCA via ERK signaling, which provides a potential target for BRCA treatment.
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Affiliation(s)
- Xiaochen Yang
- Department of Thyroid and Breast Surgery, Affiliated Kunshan Hospital of Jiangsu University, China
| | - Yukai Tao
- Clinical Research & Lab Center, Affiliated Kunshan Hospital of Jiangsu University, China
| | - Yan Xu
- Department of Thyroid and Breast Surgery, Affiliated Kunshan Hospital of Jiangsu University, China
| | - Weili Cai
- Institute of Medical Genetics and Reproductive Immunity, The Digestive and Reproductive System Cancers Precise Prevention Engineering Research Center of Jiangsu Province, Jiangsu College of Nursing, Huai'an, China
| | - Qixiang Shao
- Clinical Research & Lab Center, Affiliated Kunshan Hospital of Jiangsu University, China
- Institute of Medical Genetics and Reproductive Immunity, The Digestive and Reproductive System Cancers Precise Prevention Engineering Research Center of Jiangsu Province, Jiangsu College of Nursing, Huai'an, China
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2
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Yüksel MF, Doğulu N, Yıldırım M, Köse E, Bektaş Ö, Eminoğlu FT, Teber S. Metabolic etiologies in children with infantile epileptic spasm syndrome: Experience at a tertiary pediatric neurology center. Brain Dev 2024:S0387-7604(24)00042-1. [PMID: 38493042 DOI: 10.1016/j.braindev.2024.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 03/10/2024] [Accepted: 03/11/2024] [Indexed: 03/18/2024]
Abstract
OBJECTIVE Infantile epileptic spasm syndrome (IESS), including West syndrome (WS) and infantile spasm (IS), causes a challenging prognosis, particularly when associated with metabolic etiologies. METHODS This study, conducted at a tertiary pediatric neurology center, explored the prevalence and clinical features of inborn errors of metabolism in 112 children with IESS over 10 years. RESULTS Most patients presented with seizures, primarily flexor spasms, and the median age at onset was 5 months. Comprehensive clinical evaluation and neuroimaging revealed structural-acquired causes as the most common etiology. Notably, inborn errors of metabolism were identified in 5.4 % of cases, with six distinct diagnoses including nonketotic hyperglycinemia, pyridoxine-dependent epilepsy, primary coenzyme Q10 deficiency 7, congenital disorder of glycosylation type IIM, 6-pyruvoyl tetrahydrobiopterin synthase deficiency, and argininosuccinate lyase deficiency. The prevalence of inborn errors of metabolism in this cohort was consistent with global variations reported in the literature. Genetic testing, including karyotype analysis and whole exome sequencing, was performed in a subset of cases with no clear diagnosis, revealing abnormalities in approximately 50 % of cases. Adrenocorticotropic hormone emerged as the most frequently prescribed antiseizure medication. CONCLUSION This study provides insight into the diagnostic challenges associated with IESS and highlights the importance of metabolic investigations, especially in cases without a clear etiology. The findings emphasize the need for further genetic and metabolic studies to enhance prognostic accuracy and guide potential treatment options for children with IESS, particularly in populations with high rates of consanguinity.
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Affiliation(s)
- Merve Feyza Yüksel
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey.
| | - Neslihan Doğulu
- Department of Pediatric Metabolism, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Miraç Yıldırım
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Engin Köse
- Department of Pediatric Metabolism, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Ömer Bektaş
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Fatma Tuba Eminoğlu
- Department of Pediatric Metabolism, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Serap Teber
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
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3
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Elziny S, Crino PB, Winawer M. SLC35A2 somatic variants in drug resistant epilepsy: FCD and MOGHE. Neurobiol Dis 2023; 187:106299. [PMID: 37739137 PMCID: PMC10994450 DOI: 10.1016/j.nbd.2023.106299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 09/24/2023] Open
Abstract
De novo somatic (post-zygotic) gene mutations affecting neuroglial progenitor cell types in embryonic cerebral cortex are increasingly identified in patients with drug resistant epilepsy (DRE) associated with malformations of cortical development, in particular, focal cortical dysplasias (FCD). Somatic variants in at least 16 genes have been linked to FCD type II, all encoding components of the mechanistic target of rapamycin (mTOR) pathway. FCD type II is characterized histopathologically by cytomegalic dysmorphic neurons and balloon cells. In contrast, the molecular pathogenesis of FCD I subtypes is less well understood, and histological features are characterized by alterations in columnar or laminar organization without cytomegalic dysmorphic neurons or balloon cells. In 2018, we reported somatic mutations in Solute Carrier Family 35 member A2 (SLC35A2) linked to DRE underlying FCD type I and subsequently to a new histopathological phenotype: excess oligodendrocytes and heterotopic neurons in subcortical white matter known as MOGHE (mild malformation of cortical development with oligodendroglial hyperplasia). These discoveries opened the door to studies linking somatic mutations to FCD. In this review, we discuss the biology of SLC35A2 somatic mutations in epilepsy in FCD and MOGHE, and insights into SLC35A2 epilepsy pathogenesis, describing progress to date and critical areas for investigation.
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Affiliation(s)
- Soad Elziny
- Program in Neuroscience, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, United States of America
| | - Melodie Winawer
- Department of Neurology, Columbia University, New York, NY, United States of America.
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4
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Kodríková R, Pakanová Z, Krchňák M, Šedivá M, Šesták S, Květoň F, Beke G, Šalingová A, Skalická K, Brennerová K, Jančová E, Baráth P, Mucha J, Nemčovič M. N-Glycoprofiling of SLC35A2-CDG: Patient with a Novel Hemizygous Variant. Biomedicines 2023; 11:biomedicines11020580. [PMID: 36831116 PMCID: PMC9952902 DOI: 10.3390/biomedicines11020580] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/01/2023] [Accepted: 02/14/2023] [Indexed: 02/18/2023] Open
Abstract
Congenital disorders of glycosylation (CDG) are a group of rare inherited metabolic disorders caused by a defect in the process of protein glycosylation. In this work, we present a comprehensive glycoprofile analysis of a male patient with a novel missense variant in the SLC35A2 gene, coding a galactose transporter that translocates UDP-galactose from the cytosol to the lumen of the endoplasmic reticulum and Golgi apparatus. Isoelectric focusing of serum transferrin, which resulted in a CDG type II pattern, was followed by structural analysis of transferrin and serum N-glycans, as well as the analysis of apolipoprotein CIII O-glycans by mass spectrometry. An abnormal serum N-glycoprofile with significantly increased levels of agalactosylated (Hex3HexNAc4-5 and Hex3HexNAc5Fuc1) and monogalactosylated (Hex4HexNAc4 ± NeuAc1) N-glycans was observed. Additionally, whole exome sequencing and Sanger sequencing revealed de novo hemizygous c.461T > C (p.Leu154Pro) mutation in the SLC35A2 gene. Based on the combination of biochemical, analytical, and genomic approaches, the set of distinctive N-glycan biomarkers was characterized. Potentially, the set of identified aberrant N-glycans can be specific for other variants causing SLC35A2-CDG and can distinguish this disorder from the other CDGs or other defects in the galactose metabolism.
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Affiliation(s)
- Rebeka Kodríková
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Zuzana Pakanová
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
- Correspondence:
| | - Maroš Krchňák
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Mária Šedivá
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Sergej Šesták
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Filip Květoň
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Gábor Beke
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
- Department of Genomics and Biotechnology, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská cesta 21, 845 51 Bratislava, Slovakia
| | - Anna Šalingová
- National Institute of Children’s Diseases, Center for Inherited Metabolic Disorders, Limbová 1, 833 40 Bratislava, Slovakia
| | - Katarína Skalická
- Laboratory of Clinical and Molecular Genetics, National Institute of Children’s Diseases, Limbová 1, 833 40 Bratislava, Slovakia
| | - Katarína Brennerová
- Department of Paediatrics, Faculty of Medicine of Comenius University and National Institute for Children’s Diseases, Limbová 1, 833 40 Bratislava, Slovakia
| | - Emília Jančová
- Department of Paediatrics, Faculty of Medicine of Comenius University and National Institute for Children’s Diseases, Limbová 1, 833 40 Bratislava, Slovakia
| | - Peter Baráth
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Ján Mucha
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
| | - Marek Nemčovič
- Institute of Chemistry, Centre of Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 841 04 Bratislava, Slovakia
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Huang Y, Zhang Z, Chen L. Diagnosis and prognosis of serum Fut8 for epilepsy and refractory epilepsy in children. PLoS One 2023; 18:e0284239. [PMID: 37053181 PMCID: PMC10101470 DOI: 10.1371/journal.pone.0284239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 03/27/2023] [Indexed: 04/14/2023] Open
Abstract
With adequate serum concentration of antiepileptic drugs, the epilepsy symptoms in many patients still cannot be controlled well. The alteration of glycosyltransferase has obvious influence on the pathogenesis of epilepsy. In this study, we focus on the diagnostic and prognostic value of fucosyltransferase 8 (Fut8) on epilepsy and refractory epilepsy. Serum samples of 199 patients with epilepsy, 59 patients with refractory epilepsy and 22 healthy controls who were diagnosed in Shenzhen Children's hospital from August 2018 to August 2019 were collected. The level of lectins was further analyzed by lectin chip and enzyme linked immunosorbent assay (ELISA). The diagnostic value of serum Fut8 for epilepsy and refractory epilepsy was evaluated by receiver operating characteristic curve. Finally, the difference in the recurrence rate of convulsion in patients with epilepsy or refractory epilepsy within 2 years were observed in different Fut8 expression patients. The concentration of valproic acid (VPA) were significant different between epilepsy and refractory epilepsy group. The expression of α1, 6-fucosylation and Fut8 was significantly increased in the refractory epilepsy group compared with healthy controls. The area under the curve of Fut8 as a biomarker for predicting epilepsy or refractory epilepsy was 0.620 and 0.856, respectively. There was a significant difference in the recurrence rate of convulsion within 2 years in the children with refractory epilepsy (p = 0.0493) not epilepsy (p = 0.1865) between the high and low Fut8 expression groups. Fut8 was one of the effective indicators for the diagnosis and prognosis of refractory epilepsy.
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Affiliation(s)
- Yunxiu Huang
- Department of Laboratory Medicine, Zhongshan People's Hospital, Zhongshan, Guangdong Province, China
| | - Zhou Zhang
- Department of Pharmacy, Shenzhen Children's Hospital, Shenzhen, Guangdong Province, China
| | - Linmu Chen
- Department of Pharmacy, Zhongshan People's Hospital, Zhongshan, Guangdong Province, China
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6
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Zhen L, Chen GL, Li YL, Li DZ. Fetal phenotype of SLC35A2-CDG: Enlarged cisterna magna on ultrasound. Congenit Anom (Kyoto) 2022; 62:217-219. [PMID: 35531604 DOI: 10.1111/cga.12473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 02/10/2022] [Accepted: 02/18/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Li Zhen
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, China
| | - Gui-Lan Chen
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, China
| | - Yan-Lin Li
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, China
| | - Dong-Zhi Li
- Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou, Guangdong, China
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7
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Tiivoja E, Reinson K, Muru K, Rähn K, Muhu K, Mauring L, Kahre T, Pajusalu S, Õunap K. The prevalence of inherited metabolic disorders in Estonian population over 30 years: A significant increase during study period. JIMD Rep 2022; 63:604-613. [DOI: 10.1002/jmd2.12325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/09/2022] [Accepted: 08/10/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Elis Tiivoja
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Clinical Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
| | - Karit Reinson
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Clinical Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
| | - Kai Muru
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Clinical Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
| | - Kristi Rähn
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Clinical Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
| | - Kristina Muhu
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
| | - Laura Mauring
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Eye Clinic Tartu University Hospital Tartu Estonia
| | - Tiina Kahre
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Laboratory Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
| | - Sander Pajusalu
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Laboratory Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
| | - Katrin Õunap
- Department of Clinical Genetics, Institute of Clinical Medicine University of Tartu Tartu Estonia
- Department of Clinical Genetics, Genetic and Personalized Medicine Clinic Tartu University Hospital Tartu Estonia
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8
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Kang HJ, Kim DS, Kim SH, Lee JH, Ko A, Kim SH, Lee JS, Kim HD, Kang HC. Epilepsy with SLC35A2 Brain Somatic Mutations in Mild Malformation of Cortical Development with Oligodendroglial Hyperplasia in Epilepsy (MOGHE). ANNALS OF CHILD NEUROLOGY 2022. [DOI: 10.26815/acn.2022.00073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Purpose: This study presents the characteristics of patients with mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) with SLC35A2 somatic variants in the brain who underwent epilepsy surgery and showed clinical improvement in seizures. Methods: We collected 10 patients with SLC35A2 somatic mutations in the brain who underwent surgery to treat drug-resistant epilepsy at Severance Children’s Hospital from 2014 to 2019 and retrospectively reviewed their genetic profiles, neuropathologic results, clinical features, pre-operative evaluations, and post-operative outcomes.Results: Six of the 10 patients with SCL35A2 somatic mutations in the brain had Lennox Gastaut syndrome (LGS) evolving from infantile spasms (IS), three had LGS, and one had IS. The median value of variant allele frequencies (VAFs) was 5.7% (1.7% to 5.8%; range, 1.4% to 22.9%). Nonsense mutations were the most common (50%), followed by missense mutations (40%) and a splicing site mutation (10%). Eight patients (80%) had good post-operative outcomes, with freedom from disabling seizures in five (Engel class I) and rare disabling seizures in three (Engel class II). Four of the eight patients who could be assessed for social quotient (SQ) after surgery showed SQ improvements by 12.2±6.4. Although all patients were finally diagnosed with MOGHE, seven (70%) were initially diagnosed with gliosis, two with mild malformation of cortical development, and one with no abnormality.Conclusion: All patients with SCL35A2 brain somatic mutations, even with low VAFs, had refractory epilepsy such as LGS or IS, and were finally diagnosed with MOGHE. This report is the first in Korea to our knowledge.
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Kasapkara ÇS, Ceylan AC, Özyürek H, Karakaya Molla G, Civelek Ürey B, Kıreker Köylü O, Küçükçongar Yavaş A, Sönmez FM. SLC35A2-CDG: novel variants with two ends of the spectrum. J Pediatr Endocrinol Metab 2021; 34:1185-1189. [PMID: 34161696 DOI: 10.1515/jpem-2021-0292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 05/25/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Congenital disorders of glycosylation (CDGs) are rare inherited metabolic disorders associated with facial dysmorphism and in the majority of the patients, there is an important neurological impairment. Epilepsy was a main concern in rare forms of the disease. There are two groups of the disease: CDG-I results from the defects in glycan addition to the N-terminal and CDG-II occurs due to defects in the processing of protein bound glycans. SLC35A2-CDG is a rare form of CDG caused by mutations in the X-linked gene that encodes a UDP-Galactose transporter. The manifestations of the disease include seizures, failure to thrive, delayed myelination, and cerebral atrophy. CASE PRESENTATION We describe herein a severe female child with intractable seizures, microcephaly, growth retardation, hypotonia, global developmental delay, facial dysmorphism, skeletal findings, cerebral/cerebellar atrophy, and thin corpus callosum, and a mildly affected male carrying a novel variant with seizures and mild global developmental delay who were found by whole exome sequencing (WES) for SLC35A2 mutations previously not reported. CONCLUSIONS Our findings expand the number of reported cases and add novel variants to the repertoire of SLC35A2-CDG.
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Affiliation(s)
- Çiğdem Seher Kasapkara
- Department of Pediatric Metabolism, Ankara City Hospital, Ankara Yıldırım Beyazıt University, Ankara, Turkey
| | - Ahmet Cevdet Ceylan
- Department of Medical Genetics, Ankara City Hospital, Ankara Yıldırım Beyazıt University, Ankara, Turkey
| | - Hamit Özyürek
- Department of Pediatric Neurology, Ankara City Hospital, Ankara, Turkey
| | | | - Burcu Civelek Ürey
- Department of Pediatric Metabolism, Ankara City Hospital, Ankara, Turkey
| | - Oya Kıreker Köylü
- Department of Pediatric Metabolism, Ankara City Hospital, Ankara, Turkey
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10
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Abuduxikuer K, Wang JS. Four New Cases of SLC35A2-CDG With Novel Mutations and Clinical Features. Front Genet 2021; 12:658786. [PMID: 34122512 PMCID: PMC8191577 DOI: 10.3389/fgene.2021.658786] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/27/2021] [Indexed: 11/13/2022] Open
Abstract
SLC35A2-CDG is a rare type of X-linked CDG with more than 60 reported cases. We retrospectively analyzed clinical phenotypes and SLC35A2 genotypes of four cases of SLC35A2-CDG from four unrelated families of Han ethnicity in China. All patients had infantile onset epilepsies that were completely or partly resistant to multiple anti-epileptic medications or ketogenic diet. Three patients had severe developmental delay. All patients were female patients carrying de novo deleterious mutations in SLC35A2 (NM_001042498.2) gene, including one canonical splice-site mutation (c.426+1G > A), one large deletion (c.-322_c.274+1del), and two frameshift mutations leading to premature stop codon (c.781delC/p.Arg289ValfsTer88 and c.601delG/p.Ala201GlnfsTer148). Novel clinical features in some of our patients include anemia, hypertriglyceridemia, hypertonia, small ears, extra folds on earlobes, and maternal oligohydramnios or hypothyroidism during pregnancy. In one patient, concomitant Marfan syndrome was confirmed for having positive family history, carrying a heterozygous known disease-causing mutation in FBN1 gene (c.7240C > T/p.Arg2414Ter), and presence of typical features (rachnodactyly, ventrical septal defect, and mitral valve regurgitation). In conclusion, we expanded clinical phenotype and genetic mutation spectrum of SLC35A2-CDG by reporting four new cases with novel pathogenic variants and novel clinical features.
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Affiliation(s)
| | - Jian-She Wang
- Department of Hepatology, Children's Hospital of Fudan University, Shanghai, China
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11
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İnci A, Cengiz B, Biberoğlu G, Okur İ, Arhan E, Öner AY, Kasapkara ÇS, Küçükçongar A, Tümer L, Ezgu F. Congenital defects of glycosylation: Novel presentations with mainly neurological involvement and variable dysmorphic features. Am J Med Genet A 2021; 185:2739-2747. [PMID: 33960646 DOI: 10.1002/ajmg.a.62247] [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: 12/31/2020] [Revised: 04/01/2021] [Accepted: 04/09/2021] [Indexed: 11/09/2022]
Abstract
The pathophysiology of congenital defects of glycosylation (CDG) is complex and the diagnosis has been a challenge because of the overlapping clinical signs and symptoms as well as a large number of disorders. Isoelectric focusing of transferrin has been used as a screening method but has limitations. Individual enzyme or molecular genetic tests have been difficult to perform. In this study, we aimed to describe CDG patients who were referred to from different departments either without a preliminary diagnosis or suspected to have a genetic disorder other than CDG. The patients were diagnosed mainly with a 450 gene next-generation DNA sequencing panel for inborn errors of metabolism, which also included 25 genes for CDG. A total of 862 patients were investigated with the panel, whereby homozygous (10) or compound heterozygous (4) mutations were found in a total of 14 (1.6%) patients. A total of 13 different mutations were discovered, 10 of them being novel. Interestingly, none of the patients was suspected to have a CDG before referral. This report expands the clinical/laboratory findings in patients with CDG and stresses on the fact that CDG should be in the differential list for pediatric patients presented with nonspecific dysmorphic features and neurological delays/regression. Also, next-generation DNA sequencing with panel approach was noticed to have a significant diagnostic potential in patients presented with nonspecific neurologic and dysmorphic findings.
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Affiliation(s)
- Aslı İnci
- Faculty of Medicine, Department of Metabolic Diseases, Gazi University, Ankara, Turkey
| | - Başak Cengiz
- Faculty of Medicine, Department of Metabolic Diseases, Gazi University, Ankara, Turkey
| | - Gürsel Biberoğlu
- Faculty of Medicine, Department of Metabolic Diseases, Gazi University, Ankara, Turkey
| | - İlyas Okur
- Faculty of Medicine, Department of Metabolic Diseases, Gazi University, Ankara, Turkey
| | - Ebru Arhan
- Faculty of Medicine, Department of Pediatric Neurology, Gazi University, Ankara, Turkey
| | - Ali Yusuf Öner
- Faculty of Medicine, Department of Radiology, Gazi University, Ankara, Turkey
| | | | - Aynur Küçükçongar
- Ankara City Hospital, Department of Metabolic Disorders, Ankara, Turkey
| | - Leyla Tümer
- Faculty of Medicine, Department of Metabolic Diseases, Gazi University, Ankara, Turkey
| | - Fatih Ezgu
- Faculty of Medicine, Department of Metabolic Diseases, Gazi University, Ankara, Turkey
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12
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Conte F, van Buuringen N, Voermans NC, Lefeber DJ. Galactose in human metabolism, glycosylation and congenital metabolic diseases: Time for a closer look. Biochim Biophys Acta Gen Subj 2021; 1865:129898. [PMID: 33878388 DOI: 10.1016/j.bbagen.2021.129898] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/30/2021] [Accepted: 04/06/2021] [Indexed: 12/12/2022]
Abstract
Galactose is an essential carbohydrate for cellular metabolism, as it contributes to energy production and storage in several human tissues while also being a precursor for glycosylation. Galactosylated glycoconjugates, such as glycoproteins, keratan sulfate-containing proteoglycans and glycolipids, exert a plethora of biological functions, including structural support, cellular adhesion, intracellular signaling and many more. The biological relevance of galactose is further entailed by the number of pathogenic conditions consequent to defects in galactosylation and galactose homeostasis. The growing number of rare congenital disorders involving galactose along with its recent therapeutical applications are drawing increasing attention to galactose metabolism. In this review, we aim to draw a comprehensive overview of the biological functions of galactose in human cells, including its metabolism and its role in glycosylation, and to provide a systematic description of all known congenital metabolic disorders resulting from alterations of its homeostasis.
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Affiliation(s)
- Federica Conte
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Nicole van Buuringen
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Nicol C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Dirk J Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, the Netherlands; Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
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13
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Quelhas D, Martins E, Azevedo L, Bandeira A, Diogo L, Garcia P, Sequeira S, Ferreira AC, Teles EL, Rodrigues E, Fortuna AM, Mendonça C, Fernandes HC, Medeira A, Gaspar A, Janeiro P, Oliveira A, Laranjeira F, Ribeiro I, Souche E, Race V, Keldermans L, Matthijs G, Jaeken J. Congenital Disorders of Glycosylation in Portugal-Two Decades of Experience. J Pediatr 2021; 231:148-156. [PMID: 33340551 DOI: 10.1016/j.jpeds.2020.12.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/09/2020] [Accepted: 12/10/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To describe the clinical, biochemical, and genetic features of both new and previously reported patients with congenital disorders of glycosylation (CDGs) diagnosed in Portugal over the last 20 years. STUDY DESIGN The cohort includes patients with an unexplained multisystem or single organ involvement, with or without psychomotor disability. Serum sialotransferrin isoforms and, whenever necessary, apolipoprotein CIII isoforms and glycan structures were analyzed. Additional studies included measurement of phosphomannomutase (PMM) activity and analysis of lipid-linked oligosaccharides in fibroblasts. Sanger sequencing and massive parallel sequencing were used to identify causal variants or the affected gene, respectively. RESULTS Sixty-three individuals were diagnosed covering 14 distinct CDGs; 43 patients diagnosed postnatally revealed a type 1, 14 a type 2, and 2 a normal pattern on serum transferrin isoelectrofocusing. The latter patients were identified by whole exome sequencing. Nine of them presented also a hypoglycosylation pattern on apolipoprotein CIII isoelectrofocusing, pointing to an associated O-glycosylation defect. Most of the patients (62%) are PMM2-CDG and the remaining carry pathogenic variants in ALG1, ATP6AP1, ATP6AP2, ATP6V0A2, CCDC115, COG1, COG4, DPAGT1, MAN1B1, SLC35A2, SRD5A3, RFT1, or PGM1. CONCLUSIONS Portuguese patients with CDGs are presented in this report, some of them showing unique clinical phenotypes. Among the 14 genes mutated in Portuguese individuals, 8 are shared with a previously reported Spanish cohort. However, regarding the mutational spectrum of PMM2-CDG, the most frequent CDG, a striking similarity between the 2 populations was found, as only 1 mutated allele found in the Portuguese group has not been reported in Spain.
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Affiliation(s)
- Dulce Quelhas
- Unidade de Bioquímica Genética, Centro de Genética Médica, Centro Hospitalar Universitário do Porto, Porto, Portugal; Unit for Multidisciplinary Research in Biomedicine, ICBAS, UP, Porto, Portugal; Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto, Porto, Portugal.
| | - Esmeralda Martins
- Unit for Multidisciplinary Research in Biomedicine, ICBAS, UP, Porto, Portugal; Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Luísa Azevedo
- i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Population Genetics and Evolution Group, Porto, Portugal; IPATIMUP-Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal; FCUP-Department of Biology, Faculty of Sciences, University of Porto, Porto, Portugal
| | - Anabela Bandeira
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - Luísa Diogo
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal
| | - Paula Garcia
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Coimbra, Coimbra, Portugal
| | - Sílvia Sequeira
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
| | - Ana Cristina Ferreira
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Lisboa Central, Lisboa, Portugal
| | - Elisa Leão Teles
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de S João, Porto, Portugal
| | - Esmeralda Rodrigues
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de S João, Porto, Portugal
| | - Ana Maria Fortuna
- Unidade de Genética Médica, Centro Genética Médica, Centro Hospitalar do Porto, Porto, Portugal
| | - Carla Mendonça
- Centro de Neuropediatria e Desenvolvimento, Centro Hospitalar Universitário do Algarve, Faro, Portugal
| | | | | | - Ana Gaspar
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Sta Maria, CHLN, Lisboa, Portugal
| | - Patrícia Janeiro
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Sta Maria, CHLN, Lisboa, Portugal
| | - Anabela Oliveira
- Centro Referência Doenças Hereditárias do Metabolismo, Centro Hospitalar Universitário de Sta Maria, CHLN, Lisboa, Portugal
| | - Francisco Laranjeira
- Unidade de Bioquímica Genética, Centro de Genética Médica, Centro Hospitalar Universitário do Porto, Porto, Portugal; Unit for Multidisciplinary Research in Biomedicine, ICBAS, UP, Porto, Portugal
| | - Isaura Ribeiro
- Unidade de Bioquímica Genética, Centro de Genética Médica, Centro Hospitalar Universitário do Porto, Porto, Portugal; Unit for Multidisciplinary Research in Biomedicine, ICBAS, UP, Porto, Portugal
| | - Erica Souche
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Valérie Race
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | | | - Gert Matthijs
- Department of Human Genetics, KU Leuven, Leuven, Belgium
| | - Jaak Jaeken
- Center for Metabolic Diseases, KU Leuven, Leuven, Belgium
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SLC35A2-CDG: Novel variant and review. Mol Genet Metab Rep 2021; 26:100717. [PMID: 33552911 PMCID: PMC7851840 DOI: 10.1016/j.ymgmr.2021.100717] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/17/2021] [Accepted: 01/18/2021] [Indexed: 12/11/2022] Open
Abstract
SLC35A2 encodes the X-linked transporter that carries uridine diphosphate (UDP)-galactose from the cytosol to the lumen of the Golgi apparatus and the endoplasmic reticulum. Pathogenic variants have been associated to a congenital disorder of glycosylation (CDG) with epileptic encephalopathy as a predominant feature. Among the sixty five patients described so far, a strong gender bias is observed as only seven patients are males. This work is a review and reports a SLC35A2-CDG in a male without epilepsy and with growth deficiency associated with decreased serum IGF1, minor neurological involvement, minor facial dysmorphism, and camptodactyly of fingers and toes. Sequence analysis revealed a hemizygosity for a novel de novo variant: c.233A > G (p.Lys78Arg) in SLC35A2. Further analysis of SLC35A2 sequence by comparing both orthologous and paralogous positions, revealed that not only the variant found in this study, but also most of the reported mutated positions are conserved in SLC35A2 orthologous, and many even in the paralogous SLC35A1 and SLC35A3. This is strong evidence that replacements at these positions will have a critical pathological effect and may also explain the gender bias observed among SLC35A2-CDG patients.
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15
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Paprocka J, Jezela-Stanek A, Tylki-Szymańska A, Grunewald S. Congenital Disorders of Glycosylation from a Neurological Perspective. Brain Sci 2021; 11:brainsci11010088. [PMID: 33440761 PMCID: PMC7827962 DOI: 10.3390/brainsci11010088] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 01/01/2021] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
Most plasma proteins, cell membrane proteins and other proteins are glycoproteins with sugar chains attached to the polypeptide-glycans. Glycosylation is the main element of the post-translational transformation of most human proteins. Since glycosylation processes are necessary for many different biological processes, patients present a diverse spectrum of phenotypes and severity of symptoms. The most frequently observed neurological symptoms in congenital disorders of glycosylation (CDG) are: epilepsy, intellectual disability, myopathies, neuropathies and stroke-like episodes. Epilepsy is seen in many CDG subtypes and particularly present in the case of mutations in the following genes: ALG13, DOLK, DPAGT1, SLC35A2, ST3GAL3, PIGA, PIGW, ST3GAL5. On brain neuroimaging, atrophic changes of the cerebellum and cerebrum are frequently seen. Brain malformations particularly in the group of dystroglycanopathies are reported. Despite the growing number of CDG patients in the world and often neurological symptoms dominating in the clinical picture, the number of performed screening tests eg transferrin isoforms is systematically decreasing as broadened genetic testing is recently more favored. The aim of the review is the summary of selected neurological symptoms in CDG described in the literature in one paper. It is especially important for pediatric neurologists not experienced in the field of metabolic medicine. It may help to facilitate the diagnosis of this expanding group of disorders. Biochemically, this paper focuses on protein glycosylation abnormalities.
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Affiliation(s)
- Justyna Paprocka
- Department of Pediatric Neurology, Faculty of Medical Science in Katowice, Medical University of Silesia, 40-752 Katowice, Poland
- Correspondence: ; Tel.: +48-606-415-888
| | - Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, 01-138 Warsaw, Poland;
| | - Anna Tylki-Szymańska
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children’s Memorial Health Institute, W 04-730 Warsaw, Poland;
| | - Stephanie Grunewald
- NIHR Biomedical Research Center (BRC), Metabolic Unit, Great Ormond Street Hospital and Institute of Child Health, University College London, London SE1 9RT, UK;
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16
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Starosta RT, Boyer S, Tahata S, Raymond K, Lee HE, Wolfe LA, Lam C, Edmondson AC, Schwartz IVD, Morava E. Liver manifestations in a cohort of 39 patients with congenital disorders of glycosylation: pin-pointing the characteristics of liver injury and proposing recommendations for follow-up. Orphanet J Rare Dis 2021; 16:20. [PMID: 33413482 PMCID: PMC7788939 DOI: 10.1186/s13023-020-01630-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/27/2020] [Indexed: 12/19/2022] Open
Abstract
Background The congenital disorders of glycosylation (CDG) are a heterogeneous group of rare metabolic diseases with multi-system involvement. The liver phenotype of CDG varies not only according to the specific disorder, but also from patient to patient. In this study, we sought to identify common patterns of liver injury among patients with a broad spectrum of CDG, and to provide recommendations for follow-up in clinical practice. Methods Patients were enrolled in the Frontiers in Congenital Disorders of Glycosylation natural history study. We analyzed clinical history, molecular genetics, serum markers of liver injury, liver ultrasonography and transient elastography, liver histopathology (when available), and clinical scores of 39 patients with 16 different CDG types (PMM2-CDG, n = 19), with a median age of 7 years (range: 10 months to 65 years). For patients with disorders which are treatable by specific interventions, we have added a description of liver parameters on treatment. Results Our principal findings are (1) there is a clear pattern in the evolution of the hepatocellular injury markers alanine aminotransferase and aspartate aminotransferase according to age, especially in PMM2-CDG patients but also in other CDG-I, and that the cholangiocellular injury marker gamma-glutamyltransferase is not elevated in most patients, pointing to an exclusive hepatocellular origin of injury; (2) there is a dissociation between liver ultrasound and transient elastography regarding signs of liver fibrosis; (3) histopathological findings in liver tissue of PMM2-CDG patients include cytoplasmic glycogen deposits; and (4) most CDG types show more than one type of liver injury.
Conclusions Based on these findings, we recommend that all CDG patients have regular systematic, comprehensive screening for liver disease, including physical examination (for hepatomegaly and signs of liver failure), laboratory tests (serum alanine aminotransferase and aspartate aminotransferase), liver ultrasound (for steatosis and liver tumors), and liver elastography (for fibrosis).
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Affiliation(s)
- Rodrigo Tzovenos Starosta
- Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil. .,Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA. .,Department of Pediatrics, Washington University in Saint Louis, St. Louis, MO, USA.
| | - Suzanne Boyer
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA
| | - Shawn Tahata
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | - Kimiyo Raymond
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Hee Eun Lee
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA
| | - Lynne A Wolfe
- Undiagnosed Diseases Program, Common Fund, National Institutes of Health, Bethesda, MD, USA
| | - Christina Lam
- Division of Genetic Medicine, University of Washington, Seattle, WA, USA.,Center of Integrated Brain Research, Seattle Children's Research Institute, Seattle, WA, USA
| | - Andrew C Edmondson
- Section of Biochemical Genetics, Division of Human Genetics, Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Ida Vanessa Doederlein Schwartz
- Graduate Program in Genetics and Molecular Biology, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Service of Medical Genetics, Hospital de Clínicas de Porto Alegre, UFRGS, Porto Alegre, RS, Brazil
| | - Eva Morava
- Department of Clinical Genomics, Mayo Clinic, Rochester, MN, USA.,Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.,Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA
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17
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Bonduelle T, Hartlieb T, Baldassari S, Sim NS, Kim SH, Kang HC, Kobow K, Coras R, Chipaux M, Dorfmüller G, Adle-Biassette H, Aronica E, Lee JH, Blumcke I, Baulac S. Frequent SLC35A2 brain mosaicism in mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE). Acta Neuropathol Commun 2021; 9:3. [PMID: 33407896 PMCID: PMC7788938 DOI: 10.1186/s40478-020-01085-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 11/18/2020] [Indexed: 12/14/2022] Open
Abstract
Focal malformations of cortical development (MCD) are linked to somatic brain mutations occurring during neurodevelopment. Mild malformation of cortical development with oligodendroglial hyperplasia in epilepsy (MOGHE) is a newly recognized clinico-pathological entity associated with pediatric drug-resistant focal epilepsy, and amenable to neurosurgical treatment. MOGHE is histopathologically characterized by clusters of increased oligodendroglial cell densities, patchy zones of hypomyelination, and heterotopic neurons in the white matter. The molecular etiology of MOGHE remained unknown so far. We hypothesized a contribution of mosaic brain variants and performed deep targeted gene sequencing on 20 surgical MOGHE brain samples from a single-center cohort of pediatric patients. We identified somatic pathogenic SLC35A2 variants in 9/20 (45%) patients with mosaic rates ranging from 7 to 52%. SLC35A2 encodes a UDP-galactose transporter, previously implicated in other malformations of cortical development (MCD) and a rare type of congenital disorder of glycosylation. To further clarify the histological features of SLC35A2-brain tissues, we then collected 17 samples with pathogenic SLC35A2 variants from a multicenter cohort of MCD cases. Histopathological reassessment including anti-Olig2 staining confirmed a MOGHE diagnosis in all cases. Analysis by droplet digital PCR of pools of microdissected cells from one MOGHE tissue revealed a variant enrichment in clustered oligodendroglial cells and heterotopic neurons. Through an international consortium, we assembled an unprecedented series of 26 SLC35A2-MOGHE cases providing evidence that mosaic SLC35A2 variants, likely occurred in a neuroglial progenitor cell during brain development, are a genetic marker for MOGHE.
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18
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Haouari W, Dubail J, Lounis-Ouaras S, Prada P, Bennani R, Roseau C, Huber C, Afenjar A, Colin E, Vuillaumier-Barrot S, Seta N, Foulquier F, Poüs C, Cormier-Daire V, Bruneel A. Serum bikunin isoforms in congenital disorders of glycosylation and linkeropathies. J Inherit Metab Dis 2020; 43:1349-1359. [PMID: 32700771 DOI: 10.1002/jimd.12291] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/18/2020] [Accepted: 07/21/2020] [Indexed: 12/20/2022]
Abstract
Bikunin (Bkn) isoforms are serum chondroitin sulfate (CS) proteoglycans synthesized by the liver. They include two light forms, that is, the Bkn core protein and the Bkn linked to the CS chain (urinary trypsin inhibitor [UTI]), and two heavy forms, that is, pro-α-trypsin inhibitor and inter-α-trypsin inhibitor, corresponding to UTI esterified by one or two heavy chains glycoproteins, respectively. We previously showed that the Western-blot analysis of the light forms could allow the fast and easy detection of patients with linkeropathy, deficient in enzymes involved in the synthesis of the initial common tetrasaccharide linker of glycosaminoglycans. Here, we analyzed all serum Bkn isoforms in a context of congenital disorders of glycosylation (CDG) and showed very specific abnormal patterns suggesting potential interests for their screening and diagnosis. In particular, genetic deficiencies in V-ATPase (ATP6V0A2-CDG, CCDC115-CDG, ATP6AP1-CDG), in Golgi manganese homeostasis (TMEM165-CDG) and in the N-acetyl-glucosamine Golgi transport (SLC35A3-CDG) all share specific abnormal Bkn patterns. Furthermore, for each studied linkeropathy, we show that the light abnormal Bkn could be further in-depth characterized by two-dimensional electrophoresis. Moreover, besides being interesting as a specific biomarker of both CDG and linkeropathies, Bkn isoforms' analyses can provide new insights into the pathophysiology of the aforementioned diseases.
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Affiliation(s)
- Walid Haouari
- INSERM UMR1193, Université Paris-Saclay, Châtenay-Malabry, France
| | - Johanne Dubail
- Department of Clinical Genetics and Reference Centre for Constitutional Bone Diseases, INSERM U1163, Université de Paris, Imagine Institute, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Samra Lounis-Ouaras
- INSERM UMR1193, Université Paris-Saclay, Châtenay-Malabry, France
- AP-HP, Biochimie-Hormonologie, Hôpital Antoine Béclère, Clamart, France
| | - Pierre Prada
- AP-HP, Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, Paris, France
| | - Rizk Bennani
- AP-HP, Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, Paris, France
| | - Charles Roseau
- INSERM UMR1193, Université Paris-Saclay, Châtenay-Malabry, France
| | - Céline Huber
- Department of Clinical Genetics and Reference Centre for Constitutional Bone Diseases, INSERM U1163, Université de Paris, Imagine Institute, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Alexandra Afenjar
- Département de Génétique et Embryologie Médicale, Sorbonne Universités, Centre de Référence Malformations et Maladies Congénitales du Cervelet et Déficiences Intellectuelles de Causes Rares, Hôpital Trousseau, AP-HP, Paris, France
| | - Estelle Colin
- Department of Biochemistry and Genetics, University Hospital, Angers, France
- MitoLab Team, Institut MitoVasc, UMR CNRS6015, INSERM U1083, Angers, France
| | | | - Nathalie Seta
- AP-HP, Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, Paris, France
- Université de Paris, Paris, France
| | - François Foulquier
- Université de Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, Lille, France
| | - Christian Poüs
- INSERM UMR1193, Université Paris-Saclay, Châtenay-Malabry, France
- AP-HP, Biochimie-Hormonologie, Hôpital Antoine Béclère, Clamart, France
| | - Valérie Cormier-Daire
- Department of Clinical Genetics and Reference Centre for Constitutional Bone Diseases, INSERM U1163, Université de Paris, Imagine Institute, Necker-Enfants Malades Hospital, AP-HP, Paris, France
| | - Arnaud Bruneel
- INSERM UMR1193, Université Paris-Saclay, Châtenay-Malabry, France
- AP-HP, Biochimie Métabolique et Cellulaire, Hôpital Bichat-Claude Bernard, Paris, France
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19
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Dissecting Total Plasma and Protein-Specific Glycosylation Profiles in Congenital Disorders of Glycosylation. Int J Mol Sci 2020; 21:ijms21207635. [PMID: 33076454 PMCID: PMC7589176 DOI: 10.3390/ijms21207635] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/09/2020] [Accepted: 10/14/2020] [Indexed: 12/16/2022] Open
Abstract
Protein N-glycosylation is a multifactorial process involved in many biological processes. A broad range of congenital disorders of glycosylation (CDGs) have been described that feature defects in protein N-glycan biosynthesis. Here, we present insights into the disrupted N-glycosylation of various CDG patients exhibiting defects in the transport of nucleotide sugars, Golgi glycosylation or Golgi trafficking. We studied enzymatically released N-glycans of total plasma proteins and affinity purified immunoglobulin G (IgG) from patients and healthy controls using mass spectrometry (MS). The applied method allowed the differentiation of sialic acid linkage isomers via their derivatization. Furthermore, protein-specific glycan profiles were quantified for transferrin and IgG Fc using electrospray ionization MS of intact proteins and glycopeptides, respectively. Next to the previously described glycomic effects, we report unprecedented sialic linkage-specific effects. Defects in proteins involved in Golgi trafficking (COG5-CDG) and CMP-sialic acid transport (SLC35A1-CDG) resulted in lower levels of sialylated structures on plasma proteins as compared to healthy controls. Findings for these specific CDGs include a more pronounced effect for α2,3-sialylation than for α2,6-sialylation. The diverse abnormalities in glycomic features described in this study reflect the broad range of biological mechanisms that influence protein glycosylation.
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20
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Abstract
In this review, we focus on the metabolism of mammalian glycan-associated monosaccharides, where the vast majority of our current knowledge comes from research done during the 1960s and 1970s. Most monosaccharides enter the cell using distinct, often tissue specific transporters from the SLC2A family. If not catabolized, these monosaccharides can be activated to donor nucleotide sugars and used for glycan synthesis. Apart from exogenous and dietary sources, all monosaccharides and their associated nucleotide sugars can be synthesized de novo, using mostly glucose to produce all nine nucleotide sugars present in human cells. Today, monosaccharides are used as treatment options for a small number of rare genetic disorders and even some common conditions. Here, we cover therapeutic applications of these sugars and highlight biochemical gaps that must be revisited as we go forward.
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Affiliation(s)
- Paulina Sosicka
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, United States
| | - Bobby G. Ng
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, United States
| | - Hudson H. Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California 92037, United States
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21
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Goldman AM. What does a defect in N-glycosylation mean for neuronal migration and function? Neurol Genet 2020; 6:e490. [PMID: 32754647 PMCID: PMC7357410 DOI: 10.1212/nxg.0000000000000490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Alica M Goldman
- Department of Neurology, Baylor College of Medicine, Houston, TX
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22
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Zilmer M, Edmondson AC, Khetarpal SA, Alesi V, Zaki MS, Rostasy K, Madsen CG, Lepri FR, Sinibaldi L, Cusmai R, Novelli A, Issa MY, Fenger CD, Abou Jamra R, Reutter H, Briuglia S, Agolini E, Hansen L, Petäjä-Repo UE, Hintze J, Raymond KM, Liedtke K, Stanley V, Musaev D, Gleeson JG, Vitali C, O’Brien WT, Gardella E, Rubboli G, Rader DJ, Schjoldager KT, Møller RS. Novel congenital disorder of O-linked glycosylation caused by GALNT2 loss of function. Brain 2020; 143:1114-1126. [PMID: 32293671 PMCID: PMC7534148 DOI: 10.1093/brain/awaa063] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 12/30/2019] [Accepted: 01/20/2020] [Indexed: 11/13/2022] Open
Abstract
Congenital disorders of glycosylation are a growing group of rare genetic disorders caused by deficient protein and lipid glycosylation. Here, we report the clinical, biochemical, and molecular features of seven patients from four families with GALNT2-congenital disorder of glycosylation (GALNT2-CDG), an O-linked glycosylation disorder. GALNT2 encodes the Golgi-localized polypeptide N-acetyl-d-galactosamine-transferase 2 isoenzyme. GALNT2 is widely expressed in most cell types and directs initiation of mucin-type protein O-glycosylation. All patients showed loss of O-glycosylation of apolipoprotein C-III, a non-redundant substrate for GALNT2. Patients with GALNT2-CDG generally exhibit a syndrome characterized by global developmental delay, intellectual disability with language deficit, autistic features, behavioural abnormalities, epilepsy, chronic insomnia, white matter changes on brain MRI, dysmorphic features, decreased stature, and decreased high density lipoprotein cholesterol levels. Rodent (mouse and rat) models of GALNT2-CDG recapitulated much of the human phenotype, including poor growth and neurodevelopmental abnormalities. In behavioural studies, GALNT2-CDG mice demonstrated cerebellar motor deficits, decreased sociability, and impaired sensory integration and processing. The multisystem nature of phenotypes in patients and rodent models of GALNT2-CDG suggest that there are multiple non-redundant protein substrates of GALNT2 in various tissues, including brain, which are critical to normal growth and development.
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Affiliation(s)
- Monica Zilmer
- Department of Paediatrics, Danish Epilepsy Centre Filadelfia, 4293 Dianalund, Denmark
| | - Andrew C Edmondson
- Department of Pediatrics, Division of Human Genetics, Section of Biochemical Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sumeet A Khetarpal
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Viola Alesi
- Medical Genetics Department, Bambino Gesù Children’s Hospital, 00146 Rome, Italy
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt
| | - Kevin Rostasy
- Department of Paediatric Neurology, Children’s Hospital Datteln, Witten/Herdecke University, 45711 Datteln, Germany
| | - Camilla G Madsen
- Centre for Functional and Diagnostic Imaging and Research, Hvidovre Hospital, 2650 Hvidovre, Denmark
| | - Francesca R Lepri
- Medical Genetics Department, Bambino Gesù Children’s Hospital, 00146 Rome, Italy
| | - Lorenzo Sinibaldi
- Medical Genetics Department, Bambino Gesù Children’s Hospital, 00146 Rome, Italy
| | - Raffaella Cusmai
- Neurology Unit, Department of Neuroscience, Bambino Gesù Children’s Hospital, 00146 Rome, Italy
| | - Antonio Novelli
- Medical Genetics Department, Bambino Gesù Children’s Hospital, 00146 Rome, Italy
| | - Mahmoud Y Issa
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo 12311, Egypt
| | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre Filadelfia, 4293 Dianalund, Denmark
- Amplexa Genetics A/S, 5000 Odense C, Denmark
| | - Rami Abou Jamra
- Institute of Human Genetics, University of Leipzig, 04103 Leipzig, Germany
| | - Heiko Reutter
- Department of Neonatology and Pediatric Intensive Care, University Hospital of Bonn, 53012 Bonn, Germany
- Institute of Human Genetics, University Hospital of Bonn, 53012 Bonn, Germany
| | | | - Emanuele Agolini
- Medical Genetics Department, Bambino Gesù Children’s Hospital, 00146 Rome, Italy
| | - Lars Hansen
- Copenhagen Centre for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Ulla E Petäjä-Repo
- Research Unit of Biomedicine, University of Oulu, 90014 University of Oulu, Finland
| | - John Hintze
- Copenhagen Centre for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Kimiyo M Raymond
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Kristen Liedtke
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905, USA
| | - Valentina Stanley
- Laboratory for Pediatric Brain Disease, Howard Hughes Medical Institute, Rady Children’s Institute for Genomic Medicine, University of California, San Diego, CA 92093, USA
| | - Damir Musaev
- Laboratory for Pediatric Brain Disease, Howard Hughes Medical Institute, Rady Children’s Institute for Genomic Medicine, University of California, San Diego, CA 92093, USA
| | - Joseph G Gleeson
- Laboratory for Pediatric Brain Disease, Howard Hughes Medical Institute, Rady Children’s Institute for Genomic Medicine, University of California, San Diego, CA 92093, USA
| | - Cecilia Vitali
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - W Timothy O’Brien
- Institute for Translational Medicine and Therapeutics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elena Gardella
- Department of Neurophysiology, Danish Epilepsy Centre Filadelfia, 4293 Dianalund, Denmark
| | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre Filadelfia, 4293 Dianalund, Denmark
- Institute of Clinical Medicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Daniel J Rader
- Department of Pediatrics, Division of Human Genetics, Section of Biochemical Genetics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Katrine T Schjoldager
- Copenhagen Centre for Glycomics, Department of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre Filadelfia, 4293 Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, 5000 Odense C, Denmark
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23
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Therapeutic approaches in Congenital Disorders of Glycosylation (CDG) involving N-linked glycosylation: an update. Genet Med 2020; 22:268-279. [PMID: 31534212 PMCID: PMC8720509 DOI: 10.1038/s41436-019-0647-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Accepted: 08/20/2019] [Indexed: 02/07/2023] Open
Abstract
Congenital disorders of glycosylation (CDG) are a group of clinically and genetically heterogeneous metabolic disorders. Over 150 CDG types have been described. Most CDG types are ultrarare disorders. CDG types affecting N-glycosylation are the most common type of CDG with emerging therapeutic possibilities. This review is an update on the available therapies for disorders affecting the N-linked glycosylation pathway. In the first part of the review, we highlight the clinical presentation, general principles of management, and disease-specific therapies for N-linked glycosylation CDG types, organized by organ system. The second part of the review focuses on the therapeutic strategies currently available and under development. We summarize the successful (pre-) clinical application of nutritional therapies, transplantation, activated sugars, gene therapy, and pharmacological chaperones and outline the anticipated expansion of the therapeutic possibilities in CDG. We aim to provide a comprehensive update on the treatable aspects of CDG types involving N-linked glycosylation, with particular emphasis on disease-specific treatment options for the involved organ systems; call for natural history studies; and present current and future therapeutic strategies for CDG.
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Hadley B, Litfin T, Day CJ, Haselhorst T, Zhou Y, Tiralongo J. Nucleotide Sugar Transporter SLC35 Family Structure and Function. Comput Struct Biotechnol J 2019; 17:1123-1134. [PMID: 31462968 PMCID: PMC6709370 DOI: 10.1016/j.csbj.2019.08.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 08/05/2019] [Accepted: 08/05/2019] [Indexed: 12/22/2022] Open
Abstract
The covalent attachment of sugars to growing glycan chains is heavily reliant on a specific family of solute transporters (SLC35), the nucleotide sugar transporters (NSTs) that connect the synthesis of activated sugars in the nucleus or cytosol, to glycosyltransferases that reside in the lumen of the endoplasmic reticulum (ER) and/or Golgi apparatus. This review provides a timely update on recent progress in the NST field, specifically we explore several NSTs of the SLC35 family whose substrate specificity and function have been poorly understood, but where recent significant progress has been made. This includes SLC35 A4, A5 and D3, as well as progress made towards understanding the association of SLC35A2 with SLC35A3 and how this relates to their potential regulation, and how the disruption to the dilysine motif in SLC35B4 causes mislocalisation, calling into question multisubstrate NSTs and their subcellular localisation and function. We also report on the recently described first crystal structure of an NST, the SLC35D2 homolog Vrg-4 from yeast. Using this crystal structure, we have generated a new model of SLC35A1, (CMP-sialic acid transporter, CST), with structural and mechanistic predictions based on all known CST-related data, and includes an overview of reported mutations that alter transport and/or substrate recognition (both de novo and site-directed). We also present a model of the CST-del177 isoform that potentially explains why the human CST isoform remains active while the hamster CST isoform is inactive, and we provide a possible alternate access mechanism that accounts for the CST being functional as either a monomer or a homodimer. Finally we provide an update on two NST crystal structures that were published subsequent to the submission and during review of this report.
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Affiliation(s)
- Barbara Hadley
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Thomas Litfin
- School of Information and Communication Technology, Griffith University, Gold Coast Campus, Queensland 4212, Australia
| | - Chris J. Day
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Thomas Haselhorst
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
| | - Yaoqi Zhou
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
- School of Information and Communication Technology, Griffith University, Gold Coast Campus, Queensland 4212, Australia
| | - Joe Tiralongo
- Institute for Glycomics, Griffith University, Gold Coast Campus, Queensland 4222, Australia
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25
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Miyamoto S, Nakashima M, Ohashi T, Hiraide T, Kurosawa K, Yamamoto T, Takanashi J, Osaka H, Inoue K, Miyazaki T, Wada Y, Okamoto N, Saitsu H. A case of de novo splice site variant in SLC35A2 showing developmental delays, spastic paraplegia, and delayed myelination. Mol Genet Genomic Med 2019; 7:e814. [PMID: 31231989 PMCID: PMC6687661 DOI: 10.1002/mgg3.814] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Congenital disorders of glycosylation (CDGs) are genetic diseases caused by pathogenic variants of genes involved in protein or lipid glycosylation. De novo variants in the SLC35A2 gene, which encodes a UDP-galactose transporter, are responsible for CDGs with an X-linked dominant manner. Common symptoms related to SLC35A2 variants include epilepsy, psychomotor developmental delay, hypotonia, abnormal facial and skeletal features, and various magnetic resonance imaging (MRI) findings. METHODS Whole-exome sequencing was performed on the patient's DNA, and candidate variants were confirmed by Sanger sequencing. cDNA analysis was performed to assess the effect of the splice site variant using peripheral leukocytes. The X-chromosome inactivation pattern was studied using the human androgen receptor assay. RESULTS We identified a de novo splice site variant in SLC35A2 (NM_005660.2: c.274+1G>A) in a female patient who showed severe developmental delay, spastic paraplegia, mild cerebral atrophy, and delayed myelination on MRI, but no seizures. The variant led to an aberrant splicing resulting in an in-frame 33-bp insertion, which caused an 11-amino acid insertion in the presumptive cytoplasmic loop. X-inactivation pattern was random. Partial loss of galactose and sialic acid of the N-linked glycans of serum transferrin was observed. CONCLUSION This case would expand the phenotypic spectrum of SLC35A2-related disorders to delayed myelination with spasticity and no seizures.
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Affiliation(s)
- Sachiko Miyamoto
- Department of BiochemistryHamamatsu University School of MedicineHamamatsuJapan
| | - Mitsuko Nakashima
- Department of BiochemistryHamamatsu University School of MedicineHamamatsuJapan
| | - Tsukasa Ohashi
- Department of PediatricsNiigata University Medical and Dental HospitalNiigataJapan
| | - Takuya Hiraide
- Department of BiochemistryHamamatsu University School of MedicineHamamatsuJapan
| | - Kenji Kurosawa
- Division of Medical GeneticsKanagawa Children's Medical CenterYokohamaJapan
| | - Toshiyuki Yamamoto
- Tokyo Women's Medical University Institute for Integrated Medical SciencesTokyoJapan
| | - Junichi Takanashi
- Department of Pediatrics and Pediatric NeurologyTokyo Women's Medical University, Yachiyo Medical CenterYachiyoJapan
| | - Hitoshi Osaka
- Department of PediatricsJichi Medical UniversityTochigiJapan
| | - Ken Inoue
- Department of Mental Retardation & Birth Defect ResearchNational Institute of NeuroscienceNational Center of Neurology & PsychiatryJapan
| | - Takehiro Miyazaki
- Department of BiochemistryHamamatsu University School of MedicineHamamatsuJapan
| | - Yoshinao Wada
- Department of Molecular MedicineOsaka Women's and Children's HospitalOsakaJapan
| | - Nobuhiko Okamoto
- Department of Molecular MedicineOsaka Women's and Children's HospitalOsakaJapan
- Department of Medical GeneticsOsaka Women's and Children's HospitalOsakaJapan
| | - Hirotomo Saitsu
- Department of BiochemistryHamamatsu University School of MedicineHamamatsuJapan
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26
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Ye Z, McQuillan L, Poduri A, Green TE, Matsumoto N, Mefford HC, Scheffer IE, Berkovic SF, Hildebrand MS. Somatic mutation: The hidden genetics of brain malformations and focal epilepsies. Epilepsy Res 2019; 155:106161. [PMID: 31295639 DOI: 10.1016/j.eplepsyres.2019.106161] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 01/12/2023]
Abstract
Over the past decade there has been a substantial increase in genetic studies of brain malformations, fueled by the availability of improved technologies to study surgical tissue to address the hypothesis that focal lesions arise from focal, post-zygotic genetic disruptions. Traditional genetic studies of patients with malformations utilized leukocyte-derived DNA to search for germline variants, which are inherited or arise de novo in parental gametes. Recent studies have demonstrated somatic variants that arise post-zygotically also underlie brain malformations, and that somatic mutation explains a larger proportion of focal malformations than previously thought. We now know from studies of non-diseased individuals that somatic variation occurs routinely during cell division, including during early brain development when the rapid proliferation of neuronal precursor cells provides the ideal environment for somatic mutation to occur and somatic variants to accumulate. When confined to brain, pathogenic variants contribute to the "hidden genetics" of neurological diseases. With burgeoning novel high-throughput genetic technologies, somatic genetic variations are increasingly being recognized. Here we discuss accumulating evidence for the presence of somatic variants in normal brain tissue, review our current understanding of somatic variants in brain malformations associated with lesional epilepsy, and provide strategies to identify the potential contribution of somatic mutation to non-lesional epilepsies. We also discuss technologies that may improve detection of somatic variants in the future in these and other neurological conditions.
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Affiliation(s)
- Zimeng Ye
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Lara McQuillan
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, and Department of Neurology, Harvard Medical School, Boston, MA, United States
| | - Timothy E Green
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Heather C Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington and Seattle Children's Hospital, Seattle, WA, United States
| | - Ingrid E Scheffer
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia; Department of Pediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia; Department of Neurology, Royal Children's Hospital, Parkville, Victoria, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Samuel F Berkovic
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia
| | - Michael S Hildebrand
- Department of Medicine (Austin Hospital), University of Melbourne, Heidelberg, Victoria, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia.
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