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Takeuchi I, Funayama R, Shoji H, Nambu R, Jimbo K, Hara T, Shimizu H, Nomura I, Iwama I, Kudo T, Shimizu T, Arai K. Evaluation of Deficient Nutrients in Infants and Toddlers Mainly Taking Amino Acid-Based Elemental Formulas: An Exploratory Study. ANNALS OF NUTRITION & METABOLISM 2024:1-10. [PMID: 38754393 DOI: 10.1159/000539146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2023] [Accepted: 04/29/2024] [Indexed: 05/18/2024]
Abstract
INTRODUCTION This study evaluated nutrient deficiencies in infants and toddlers with inflammatory bowel disease (IBD) and eosinophilic gastrointestinal disorders (EGIDs), whose primary nutritional source is elemental formulas (EFs). METHODS The nutrient status of children with IBD and EGID aged 6 months to 6 years was evaluated. RESULTS Twenty-one children fed with EFs (EF group) and 25 controls (CL group) were enrolled. The selenium level in the EF group was lower than that in the CL group (2.2 μg/dL vs. 9.3 μg/dL; p < 0.01). Although fat-soluble vitamins were deficient in some EF group participants, no significant differences were observed in their concentration and insufficiency proportion. However, ascorbic acid deficiency was more frequent in the EF group, with significantly lower levels (8.6 μg/mL vs. 12.0 μg/mL; p < 0.01). The triene:tetraene ratio was significantly higher in the EF group (0.046 vs. 0.010; p < 0.01). Asparagine and taurine levels were significantly lower in the EF group (asparagine: p < 0.01; taurine: p < 0.01) and tyrosine and phenylalanine levels were higher in the EF group, resulting in a lower Fisher's ratio (p < 0.01). CONCLUSION Long-term feeding with EFs can cause deficiencies in essential fatty acids, selenium, and ascorbic acid and also carries a risk of amino acid imbalance in infants and toddlers.
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Affiliation(s)
- Ichiro Takeuchi
- Division of Gastroenterology, Center for Pediatric Inflammatory Bowel Disease, National Center for Child Health and Development, Tokyo, Japan
| | - Rie Funayama
- Division of Gastroenterology, Center for Pediatric Inflammatory Bowel Disease, National Center for Child Health and Development, Tokyo, Japan
| | - Hiromichi Shoji
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Ryusuke Nambu
- Division of Gastroenterology and Hepatology, Saitama Children's Medical Center, Saitama, Japan
| | - Keisuke Jimbo
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Tomoko Hara
- Division of Gastroenterology and Hepatology, Saitama Children's Medical Center, Saitama, Japan
| | - Hirotaka Shimizu
- Division of Gastroenterology, Center for Pediatric Inflammatory Bowel Disease, National Center for Child Health and Development, Tokyo, Japan
| | - Ichiro Nomura
- Division of Eosinophilic Gastrointestinal Disorders, National Research Institute for Child Health and Development, Tokyo, Japan
| | - Itaru Iwama
- Division of Gastroenterology and Hepatology, Saitama Children's Medical Center, Saitama, Japan
| | - Takahiro Kudo
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Toshiaki Shimizu
- Department of Pediatrics, Juntendo University Faculty of Medicine, Tokyo, Japan
| | - Katsuhiro Arai
- Division of Gastroenterology, Center for Pediatric Inflammatory Bowel Disease, National Center for Child Health and Development, Tokyo, Japan
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Staklinski SJ, Scheben A, Siepel A, Kilberg MS. Utility of AlphaMissense predictions in Asparagine Synthetase deficiency variant classification. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.30.564808. [PMID: 37961642 PMCID: PMC10634951 DOI: 10.1101/2023.10.30.564808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
AlphaMissense is a recently developed method that is designed to classify missense variants into pathogenic, benign, or ambiguous categories across the entire human proteome. Asparagine Synthetase Deficiency (ASNSD) is a developmental disorder associated with severe symptoms, including congenital microcephaly, seizures, and premature death. Diagnosing ASNSD relies on identifying mutations in the asparagine synthetase (ASNS) gene through DNA sequencing and determining whether these variants are pathogenic or benign. Pathogenic ASNS variants are predicted to disrupt the protein's structure and/or function, leading to asparagine depletion within cells and inhibition of cell growth. AlphaMissense offers a promising solution for the rapid classification of ASNS variants established by DNA sequencing and provides a community resource of pathogenicity scores and classifications for newly diagnosed ASNSD patients. Here, we assessed AlphaMissense's utility in ASNSD by benchmarking it against known critical residues in ASNS and evaluating its performance against a list of previously reported ASNSD-associated variants. We also present a pipeline to calculate AlphaMissense scores for any protein in the UniProt database. AlphaMissense accurately attributed a high average pathogenicity score to known critical residues within the two ASNS active sites and the connecting intramolecular tunnel. The program successfully categorized 78.9% of known ASNSD-associated missense variants as pathogenic. The remaining variants were primarily labeled as ambiguous, with a smaller proportion classified as benign. This study underscores the potential role of AlphaMissense in classifying ASNS variants in suspected cases of ASNSD, potentially providing clarity to patients and their families grappling with ongoing diagnostic uncertainty.
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Affiliation(s)
- Stephen J. Staklinski
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724
- School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724
| | - Armin Scheben
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724
| | - Adam Siepel
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724
| | - Michael S. Kilberg
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Box 100245, Gainesville, FL 326010-0245
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3
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Chang MC, Staklinski SJ, Merritt ME, Kilberg MS. A method for measurement of human asparagine synthetase (ASNS) activity and application to ASNS protein variants associated with ASNS deficiency. Biol Methods Protoc 2023; 8:bpad026. [PMID: 37965492 PMCID: PMC10641120 DOI: 10.1093/biomethods/bpad026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 11/16/2023] Open
Abstract
Human asparagine synthetase (ASNS) catalyzes the conversion of aspartate to asparagine in an ATP-dependent reaction that utilizes glutamine as a nitrogen source while generating glutamate, AMP, and pyrophosphate as additional products. Asparagine Synthetase Deficiency (ASNSD) is an inborn error of metabolism in which children present with homozygous or compound heterozygous mutations in the ASNS gene. These mutations result in ASNS variant protein expression. It is believed that these variant ASNS proteins have reduced enzymatic activity or stability resulting in a lack of sufficient asparagine production for cell function. Reduced asparagine production by ASNS appears to severely hinder fetal brain development. Although a variety of approaches for assaying ASNS activity have been reported, we present here a straightforward method for the in vitro enzymatic analysis by detection of AMP production. Our method overcomes limitations in technical feasibility, signal detection, and reproducibility experienced by prior methods like high-performance liquid chromatography, ninhydrin staining, and radioactive tracing. After purification of FLAG-tagged R49Q, G289A, and T337I ASNS variants from stably expressing HEK 293T cells, this method revealed a reduction in activity of 90, 36, and 96%, respectively. Thus, ASNS protein expression and purification, followed by enzymatic activity analysis, has provided a relatively simple protocol to evaluate structure-function relationships for ASNS variants reported for ASNSD patients.
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Affiliation(s)
- Mario C Chang
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, United States
| | - Stephen J Staklinski
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, United States
- School of Biological Sciences, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, United States
| | - Matthew E Merritt
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, United States
| | - Michael S Kilberg
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL 32610, United States
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4
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Zhu L, Sun Y, Xu Y, Jin P, Ding H, Dong M. Case report: A compound heterozygous mutations in ASNS broadens the spectrum of asparagine synthetase deficiency in the prenatal diagnosis. Front Pediatr 2023; 11:1273789. [PMID: 37900678 PMCID: PMC10611455 DOI: 10.3389/fped.2023.1273789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/29/2023] [Indexed: 10/31/2023] Open
Abstract
Asparagine synthetase deficiency (ASNSD) is a rare congenital disorder characterized by severe progressive microcephaly, global developmental delay, spastic quadriplegia, and refractory seizures. ASNSD is caused by variations of the ASNS gene. The present study showed a Chinese family with a fetus suffering microcephaly. Whole-exome sequencing and Sanger sequencing were used to identify the disease-associated genetic variants. Compound heterozygous variants c.97C>T p. (R33C) and c.1031-2_1033del were identified in the ASNS gene and the variants were inherited from the parents. The mutation site c.97C>T was highly conserved across a wide range of species and predicted to alter the local electrostatic potential. The variant c.1031-2_1033del was classified pathogenic. However, there is no case report of prenatal diagnosis of ASNSD. This is the first description of fetal compound mutations in the ASNS gene leading to ASNSD, which expanded the spectrum of ASNSD.
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Affiliation(s)
- Linyan Zhu
- Department of Obstetrics and Gynaecology, The First Affiliated Hospital of Ningbo University, Ningbo, China
- Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yixi Sun
- Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Genetics, Ministry of Education (Zhejiang University), Hangzhou, China
| | - Yuqing Xu
- Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Genetics, Ministry of Education (Zhejiang University), Hangzhou, China
| | - Pengzhen Jin
- Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Genetics, Ministry of Education (Zhejiang University), Hangzhou, China
| | - Huiqing Ding
- Department of Obstetrics and Gynaecology, The First Affiliated Hospital of Ningbo University, Ningbo, China
| | - Minyue Dong
- Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Reproductive Genetics, Ministry of Education (Zhejiang University), Hangzhou, China
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5
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Saini AG, Gunasekaran PK, Chaudhary I, Bhatia V. Severe Microcephaly and Metabolic Epilepsy due to Asparagine Synthetase Deficiency. Ann Indian Acad Neurol 2023; 26:570-572. [PMID: 37970270 PMCID: PMC10645261 DOI: 10.4103/aian.aian_414_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 05/30/2023] [Accepted: 06/24/2023] [Indexed: 11/17/2023] Open
Affiliation(s)
- Arushi G. Saini
- Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Pradeep K. Gunasekaran
- Department of Pediatrics, All India Institute of Medical Sciences, Jodhpur, Rajasthan, India
| | - Inzamam Chaudhary
- Department of Pediatrics, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Vikas Bhatia
- Department of Radiodiagnosis, Postgraduate Institute of Medical Education and Research, Chandigarh, India
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6
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Safrhansova L, Hlozkova K, Starkova J. Targeting amino acid metabolism in cancer. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2022; 373:37-79. [PMID: 36283767 DOI: 10.1016/bs.ircmb.2022.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Metabolic rewiring is a characteristic hallmark of cancer cells. This phenomenon sustains uncontrolled proliferation and resistance to apoptosis by increasing nutrients and energy supply. However, reprogramming comes together with vulnerabilities that can be used against tumor and can be applied in targeted therapy. In the last years, the genetic background of tumors has been identified thoroughly and new therapies targeting those mutations tested. Nevertheless, we propose that targeting the phenotype of cancer cells could be another way of treatment aiming to avoid drug resistance and non-responsiveness of cancer patients. Amino acid metabolism is part of the altered processes in cancer cells. Amino acids are building blocks and also sensors of signaling pathways regulating main biological processes. In this comprehensive review, we described four amino acids (asparagine, arginine, methionine, and cysteine) which have been actively investigated as potential targets for anti-tumor therapy. Asparagine depletion is successfully used for decades in the treatment of acute lymphoblastic leukemia and there is a strong implication to apply it to other types of tumors. Arginine auxotrophic tumors are great candidates for arginine-starvation therapy. Higher requirement for essential amino acids such as methionine and cysteine point out promising targetable weaknesses of cancer cells.
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Affiliation(s)
- Lucie Safrhansova
- CLIP - Childhood Leukaemia Investigation Prague, Prague, Czech Republic; Dept. of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Katerina Hlozkova
- CLIP - Childhood Leukaemia Investigation Prague, Prague, Czech Republic; Dept. of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University, Prague, Czech Republic
| | - Julia Starkova
- CLIP - Childhood Leukaemia Investigation Prague, Prague, Czech Republic; Dept. of Pediatric Hematology and Oncology, Second Faculty of Medicine, Charles University, Prague, Czech Republic; University Hospital Motol, Prague, Czech Republic.
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7
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Di Stasio F, Faraguna MC, Di Marco S, Crescitelli V, Iascone M, Florio S, Peruzzi C, Gasperini S. A Neuro-metabolic Syndrome that Needs to Be Discovered: A Child with Late Onset Asparagine Synthetase Deficiency. JOURNAL OF PEDIATRIC EPILEPSY 2021. [DOI: 10.1055/s-0041-1739488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractAsparagine synthetase (ASNS) deficiency is a rare inborn error of metabolism caused by a defect in ASNS—a gene encoding asparagine synthetase. It has mainly been described as a neurological phenotype manifesting as severe developmental delay, congenital microcephaly, spasticity, and refractory seizures; it is not associated with any specific dysmorphisms. ASNS deficiency leads to the inability to synthesize a nonessential amino acid in the brain, this explains why the symptoms are primarily neurological. The accumulation of aspartate/glutamate causes increased neuronal apoptosis leading to brain atrophy and increased neuronal excitability leading to seizures. Asparagine levels in plasma and cerebrospinal fluid are not reliable biomarkers for this disorder, therefore diagnosis is mainly obtained by molecular genetics. This disorder is associated with a poor prognosis and there is no treatment except supportive therapy. Prenatal diagnosis is possible. We report a case of a later onset form, c.146G > A (p.Arg49Gln) variant in the ASNS gene detected by molecular analysis using next-generation sequencing; the patient's clinical presentation included microcephaly, regression of developmental milestones, epilepsy, and hyperthermia.
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Affiliation(s)
- Fabiana Di Stasio
- Department of Pediatrics, Università degli Studi Milano Bicocca, Milano, Italy
| | | | - Santo Di Marco
- Department of Pediatrics, Università degli Studi Milano Bicocca, Milano, Italy
| | - Viola Crescitelli
- Department of Pediatrics, Università degli Studi Milano Bicocca, Milano, Italy
| | - Maria Iascone
- Department of Genetic Medicine, Laboratory of Genetic Medicine, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Santa Florio
- Department of Neuroradiology, San Gerardo Hospital, Monza, Italy
| | - Cinzia Peruzzi
- Department of Neuropsychiatry, San Gerardo Hospital, Monza, Italy
| | - Serena Gasperini
- Department of Pediatrics, Pediatric Rare Diseases Unit, San Gerardo Hospital, Monza, Italy
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8
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Abdel-Salam GMH, Abdel-Hamid MS. Asparagine Synthetase Deficiency with Intracranial Hemorrhage Can Mimic Molybdenum Cofactor Deficiency. Neuropediatrics 2021; 52:201-207. [PMID: 33271615 DOI: 10.1055/s-0040-1718917] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Here we report a consanguineous Egyptian family with two siblings presented with congenital microcephaly, early-onset epileptic encephalopathy, feeding difficulties, and early lethality. The condition was initially diagnosed as molybdenum cofactor deficiency as the brain imaging for one of them showed brain edema and intracranial hemorrhage in addition to the hypoplastic corpus callosum, vermis hypoplasia, and small-sized pons. Subsequently, whole exome sequencing identified a novel homozygous missense variant in exon 4 of ASNS gene c.397_398GT > CA (p.Val133Gln) confirming the diagnosis of asparagine synthetase deficiency syndrome. No discernible alternative cause for the intracranial hemorrhage was found. Our patient is the second to show asparagine synthetase deficiency and intracranial hemorrhage, thus confirming the involvement of ASNS gene. As such, it is important to consider asparagine synthetase deficiency syndrome in patients with microcephaly, brain edema, and neonatal intracranial hemorrhage.
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Affiliation(s)
- Ghada M H Abdel-Salam
- Human Genetics and Genome Research Division, Clinical Genetics Department, National Research Centre, Cairo, Egypt
| | - Mohamed S Abdel-Hamid
- Human Genetics and Genome Research Division, Medical Molecular Department, National Research Centre, Cairo, Egypt
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9
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Surasiang T, Noree C. Effects of A6E Mutation on Protein Expression and Supramolecular Assembly of Yeast Asparagine Synthetase. BIOLOGY 2021; 10:biology10040294. [PMID: 33916846 PMCID: PMC8065433 DOI: 10.3390/biology10040294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/25/2021] [Accepted: 03/31/2021] [Indexed: 11/16/2022]
Abstract
Simple Summary Certain mutations causing extremely low abundance of asparagine synthetase (the enzyme responsible for producing asparagine, one of the amino acids required for normal growth and development) have been identified in humans with neurological problems and small head and brain size. Currently, yeast is becoming more popular in modeling many human diseases. In this study, we incorporate a mutation, associated with human asparagine synthetase deficiency, into the yeast asparagine synthetase gene to demonstrate that this mutation can also show similar effects as those observed in humans, leading to very low abundance of yeast asparagine synthetase and slower yeast growth rate. This suggests that our yeast system can be alternatively used to initially screen for any drugs that can help rescue the protein levels of asparagine synthetase before applying them to further studies in mammals and humans. Furthermore, this mutation might specifically be introduced into the asparagine synthetase gene of the target cancer cells in order to suppress the overproduction of asparagine synthetase within these abnormal cells, therefore inhibiting the growth of cancer, which might be helpful for patients with blood cancer to prevent them developing any resistance to the conventional asparaginase treatment. Abstract Asparagine synthetase deficiency (ASD) has been found to be caused by certain mutations in the gene encoding human asparagine synthetase (ASNS). Among reported mutations, A6E mutation showed the greatest reduction in ASNS abundance. However, the effect of A6E mutation has not yet been tested with yeast asparagine synthetase (Asn1/2p). Here, we constructed a yeast strain by deleting ASN2 from its genome, introducing the A6E mutation codon to ASN1, along with GFP downstream of ASN1. Our mutant yeast construct showed a noticeable decrease of Asn1p(A6E)-GFP levels as compared to the control yeast expressing Asn1p(WT)-GFP. At the stationary phase, the A6E mutation also markedly lowered the assembly frequency of the enzyme. In contrast to Asn1p(WT)-GFP, Asn1p(A6E)-GFP was insensitive to changes in the intracellular energy levels upon treatment with sodium azide during the log phase or fresh glucose at the stationary phase. Our study has confirmed that the effect of A6E mutation on protein expression levels of asparagine synthetase is common in both unicellular and multicellular eukaryotes, suggesting that yeast could be a model of ASD. Furthermore, A6E mutation could be introduced to the ASNS gene of acute lymphoblastic leukemia patients to inhibit the upregulation of ASNS by cancer cells, reducing the risk of developing resistance to the asparaginase treatment.
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10
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Akesson LS, Bournazos A, Fennell A, Krzesinski EI, Tan K, Springer A, Rose K, Goranitis I, Francis D, Lee C, Faiz F, Davis MR, Christodoulou J, Lunke S, Stark Z, Hunter MF, Cooper ST. Rapid exome sequencing and adjunct RNA studies confirm the pathogenicity of a novel homozygous ASNS splicing variant in a critically ill neonate. Hum Mutat 2020; 41:1884-1891. [PMID: 32906196 DOI: 10.1002/humu.24101] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 05/09/2020] [Accepted: 08/28/2020] [Indexed: 12/13/2022]
Abstract
Rapid genomic diagnosis programs are transforming rare disease diagnosis in acute pediatrics. A ventilated newborn with cerebellar hypoplasia underwent rapid exome sequencing (75 h), identifying a novel homozygous ASNS splice-site variant (NM_133436.3:c.1476+1G>A) of uncertain significance. Rapid ASNS splicing studies using blood-derived messenger RNA from the family trio confirmed a consistent pattern of abnormal splicing induced by the variant (cryptic 5' splice-site or exon 12 skipping) with absence of normal ASNS splicing in the proband. Splicing studies reported within 10 days led to reclassification of c.1476+1G>A as pathogenic at age 27 days. Intensive care was redirected toward palliation. Cost analyses for the neonate and his undiagnosed, similarly affected deceased sibling, demonstrate that early diagnosis reduced hospitalization costs by AU$100,828. We highlight the diagnostic benefits of adjunct RNA testing to confirm the pathogenicity of splicing variants identified via rapid genomic testing pipelines for precision and preventative medicine.
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Affiliation(s)
- Lauren S Akesson
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Genetics Clinic, Monash Health, Monash Medical Centre, Clayton, Victoria, Australia
| | - Adam Bournazos
- Kids Neuroscience Centre, Children's Hospital at Westmead, Sydney, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Andrew Fennell
- Genetics Clinic, Monash Health, Monash Medical Centre, Clayton, Victoria, Australia.,Department of Paediatrics, Monash University, Melbourne, Australia
| | - Emma I Krzesinski
- Genetics Clinic, Monash Health, Monash Medical Centre, Clayton, Victoria, Australia.,Department of Paediatrics, Monash University, Melbourne, Australia
| | - Kenneth Tan
- Department of Paediatrics, Monash University, Melbourne, Australia.,Monash Newborn, Monash Health, Monash Children's Hospital, Clayton, Victoria, Australia
| | - Amanda Springer
- Genetics Clinic, Monash Health, Monash Medical Centre, Clayton, Victoria, Australia.,Department of Paediatrics, Monash University, Melbourne, Australia
| | - Katherine Rose
- Genetics Clinic, Monash Health, Monash Medical Centre, Clayton, Victoria, Australia.,Department of Paediatrics, Monash University, Melbourne, Australia
| | - Ilias Goranitis
- Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia.,Australian Genomics Health Alliance, Parkville, Victoria, Australia
| | - David Francis
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Crystle Lee
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Fathimath Faiz
- Department of Diagnostic Genomics, PathWest Laboratory Medicine, Perth, Australia
| | - Mark R Davis
- Department of Diagnostic Genomics, PathWest Laboratory Medicine, Perth, Australia
| | - John Christodoulou
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Australian Genomics Health Alliance, Parkville, Victoria, Australia.,Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, Australia
| | - Sebastian Lunke
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Australian Genomics Health Alliance, Parkville, Victoria, Australia.,Department of Clinical Pathology, University of Melbourne, Melbourne, Australia
| | - Zornitza Stark
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Parkville, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Australia.,Australian Genomics Health Alliance, Parkville, Victoria, Australia
| | - Matthew F Hunter
- Genetics Clinic, Monash Health, Monash Medical Centre, Clayton, Victoria, Australia.,Department of Paediatrics, Monash University, Melbourne, Australia
| | - Sandra T Cooper
- Kids Neuroscience Centre, Children's Hospital at Westmead, Sydney, Australia.,Faculty of Medicine and Health, University of Sydney, Sydney, Australia.,Children's Medical Research Institute, Sydney, Australia
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11
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Chen C, Hao Y, Liang J, Liu X. Congenital microcephaly with early onset epileptic encephalopathy caused by ASNS gene mutation: A case report. Medicine (Baltimore) 2020; 99:e20507. [PMID: 32481472 DOI: 10.1097/md.0000000000020507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
RATIONALE Asparagine synthetase deficiency (ASNSD) refers to a congenital metabolic abnormality caused by mutation in the asparagine synthetase (ASNS) gene encoded by chromosome 7q21. Herein, we report the first case of ASNSD in China, in which novel ASNS mutations were identified. PATIENT CONCERNS A 6-month-old boy presented with a 4-month history of microcephaly and psychomotor developmental retardation and a 2-month history of epilepsy. Four months after birth, magnetic resonance imaging demonstrated a giant cyst in the right lateral ventricle, and a ventriculoperitoneal shunt was placed. Video electroencephalography showed a hypsarrhythmia pattern with a string of tonic-clonic and myoclonic seizures. On admission, physical examination showed microcephaly. Neurologic examination showed a decreased tension in the trunk muscles and an increased tension in the extremity muscles; tendon hyperreflexia was noted, and bilateral pathologic reflexes were positive. DIAGNOSIS A diagnosed of congenital microcephaly was made. Whole-exome sequencing revealed a heterozygous deletion mutation c.666_667delCT (p.L2221Lfs*5) in exon 6 of the ASNS gene and a heterozygous missense mutation c.1424C>T (p.T457I) in exon 13 of the ASNS gene. INTERVENTIONS After admission, intravenous adrenocorticotropic hormone and oral topiramate was administrated for 4 weeks, while the seizures persisted. Then, levetiracetam and clonazepam were added. OUTCOMES After the follow-up period of 18 months, video electroencephalography showed that complex episodes disappeared with changes in multiple focal spike and sharp waves; 1 focal attack arising from the left occipital region and 2 focal attacks arising from the right middle temporal and the right occipital region were recorded. LESSONS This is the first case of ASNSD in China. We identified 2 novel mutations (c.666_667delCT and c.1424C>T) in the ASNS gene, which expands the ASNS gene mutation profile and will be beneficial for genetic diagnosis.
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Affiliation(s)
| | | | | | - Xuncan Liu
- Department of Rehabilitation, The First Hospital of Jilin University, Changchun, Jilin, China
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12
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Wang C, He G, Ge Y, Li R, Li Z, Lin Y. A novel compound heterozygous missense mutation in ASNS broadens the spectrum of asparagine synthetase deficiency. Mol Genet Genomic Med 2020; 8:e1235. [PMID: 32255274 PMCID: PMC7284041 DOI: 10.1002/mgg3.1235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/22/2020] [Accepted: 03/02/2020] [Indexed: 02/02/2023] Open
Abstract
Background Asparagine synthetase deficiency (ASNSD) is a rare pediatric congenital disorder that clinically manifests into severe progressive microcephaly, global developmental delay, spastic quadriplegia, and refractory seizures. ASNSD is caused by inheritable autosomal recessive mutations in the asparagine synthetase (ASNS) gene. Methods We performed whole‐exome sequencing using the patient's peripheral blood, and newly discovered mutations were subsequently verified in the patient's parents via Sanger sequencing. Software‐based bioinformatics analyses (protein sequence conservation analysis, prediction of protein phosphorylation sites, protein structure modeling, and protein stability prediction) were performed to investigate and deduce their downstream effects. Results In this article, we summarized all the previously reported cases of ASNSD and that of a Chinese girl who was clinically diagnosed with ASNSD, which was later confirmed via genetic testing. Whole‐exome sequencing revealed two compound heterozygous missense mutations within the ASNS (c.368T > C, p.F123S and c.1649G > A, p.R550H). The origin of the two mutations was also verified in the patient's parents via Sanger sequencing. The mutation c.368T > C (p.F123S) was discovered and confirmed to be novel and previously unreported. Using software‐based bioinformatics analyses, we deduced that the two mutation sites are highly conserved across a wide range of species, with the ability to alter different phosphorylation sites and destabilize the ASNS protein structure. The newly identified p.F123S mutation was predicted to be the most significantly destabilizing and detrimental mutation to the ASNS protein structure, compared to all other previously reported mutations. Conclusion Evidently, the presence of these compound heterozygous mutations could lead to severe clinical phenotypes and serve as a potential indicator for considerably higher risk with less optimistic prognosis in ASNSD patients.
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Affiliation(s)
- Chun Wang
- Department of NeurologyThe Second Hospital of Dalian Medical UniversityDalianChina
| | - Guiyuan He
- Center for Reproductive and Genetic MedicineDalian Municipal Women and Children’s Medical CenterDalianChina
| | - Yusong Ge
- Department of NeurologyThe Second Hospital of Dalian Medical UniversityDalianChina
| | - Runjie Li
- Department of RehabilitationDalian Municipal Women and Children’s Medical CenterDalianChina
| | - Zhenguo Li
- Clinical LaboratoryThe Second Hospital of Dalian Medical UniversityDalianChina
| | - Yongzhong Lin
- Department of NeurologyThe Second Hospital of Dalian Medical UniversityDalianChina
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13
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Perveen S, Gupta N, Kumar M, Kaur P, Chowdhury MR, Kabra M. Spectrum of amyloglucosidase mutations in Asian Indian patients with Glycogen storage disease type III. Am J Med Genet A 2020; 182:1190-1200. [PMID: 32222031 DOI: 10.1002/ajmg.a.61547] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 02/07/2020] [Accepted: 02/14/2020] [Indexed: 11/11/2022]
Abstract
Glycogen storage disease type III (GSD III) is a rare autosomal recessive inborn error of glycogen degradation pathway due to deficiency or reduced activity of glycogen debranching enzyme (GDE) that results in accumulation of abnormal glycogen in the liver, muscle, and heart. The cardinal hallmarks are hepatomegaly, fasting hypoglycemia, seizures, growth retardation, progressive skeletal myopathy, and cardiomyopathy in few. To date, 258 mutations in amyloglucosidase (AGL) gene have been identified worldwide. However, the mutation spectrum in the Asian Indian region is yet to be well characterized. We investigated 24 patients of Asian origin from 21 unrelated families with a provisional diagnosis of GSD III based on clinical and biochemical criteria. Molecular diagnosis was assessed by bidirectional sequencing and the impact of novel missense variants on the tertiary (three-dimensional) structure of GDE was evaluated by molecular modeling approach. Eighteen different pathogenic variants were identified, out of which 78% were novel. Novel variants included five nonsense, three small duplications and two small deletions, a splice site variant, and three missense variants. Variations in Exons 4, 14, 19, 24, 27, and 33 accounted for 61% of the total pathogenic variants identified and Allele p.Gly798Alafs*3 showed a high allele frequency of 11%. Molecular modeling study of novel pathogenic missense variants indicated the probable underlying molecular mechanism of adverse impact of variations on the structure and catalytic function of human GDE. Our study is the first large study on GSD III from the Asian subcontinent, which further expands the mutation spectrum of AGL.
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Affiliation(s)
- Shama Perveen
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Neerja Gupta
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Manoj Kumar
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
| | - Punit Kaur
- Department of Biophysics, All India Institute of Medical Sciences, New Delhi, India
| | - Madhumita R Chowdhury
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
| | - Madhulika Kabra
- Division of Genetics, Department of Pediatrics, All India Institute of Medical Sciences, New Delhi, India
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14
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Chiu M, Taurino G, Bianchi MG, Kilberg MS, Bussolati O. Asparagine Synthetase in Cancer: Beyond Acute Lymphoblastic Leukemia. Front Oncol 2020; 9:1480. [PMID: 31998641 PMCID: PMC6962308 DOI: 10.3389/fonc.2019.01480] [Citation(s) in RCA: 95] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 12/10/2019] [Indexed: 12/12/2022] Open
Abstract
Asparagine Synthetase (ASNS) catalyzes the synthesis of the non-essential amino acid asparagine (Asn) from aspartate (Asp) and glutamine (Gln). ASNS expression is highly regulated at the transcriptional level, being induced by both the Amino Acid Response (AAR) and the Unfolded Protein Response (UPR) pathways. Lack of ASNS protein expression is a hallmark of Acute Lymphoblastic Leukemia (ALL) blasts, which, therefore, are auxotrophic for Asn. This peculiarity is the rationale for the use of bacterial L-Asparaginase (ASNase) for ALL therapy, the first example of anti-cancer treatment targeting a tumor-specific metabolic feature. Other hematological and solid cancers express low levels of ASNS and, therefore, should also be Asn auxotrophs and ASNase sensitive. Conversely, in the last few years, several reports indicate that in some cancer types ASNS is overexpressed, promoting cell proliferation, chemoresistance, and a metastatic behavior. However, enhanced ASNS activity may constitute a metabolic vulnerability in selected cancer models, suggesting a variable and tumor-specific role of the enzyme in cancer. Recent evidence indicates that, beyond its canonical role in protein synthesis, Asn may have additional regulatory functions. These observations prompt a re-appreciation of ASNS activity in the biology of normal and cancer tissues, with particular attention to the fueling of Asn exchange between cancer cells and the tumor microenvironment.
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Affiliation(s)
- Martina Chiu
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Giuseppe Taurino
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Massimiliano G Bianchi
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - Michael S Kilberg
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville, FL, United States
| | - Ovidio Bussolati
- Laboratory of General Pathology, Department of Medicine and Surgery, University of Parma, Parma, Italy
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15
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Faoucher M, Poulat AL, Chatron N, Labalme A, Schluth-Bolard C, Till M, Vianey-Saban C, Portes VD, Edery P, Sanlaville D, Lesca G, Acquaviva C. Asparagine synthetase deficiency: A novel case with an unusual molecular mechanism. Mol Genet Metab Rep 2019; 21:100509. [PMID: 31720226 PMCID: PMC6838931 DOI: 10.1016/j.ymgmr.2019.100509] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/22/2019] [Accepted: 08/22/2019] [Indexed: 11/17/2022] Open
Abstract
We report the case of a girl with Asparagine synthetase deficiency, an autosomal recessive metabolic disorder characterized by severe microcephaly and epileptic encephalopathy secondary to pathogenic variants in the ASNS gene. Genetic explorations found a deletion of ASNS and a missense variant on the other allele detected respectively by array comparative genomic hybridization (CGH) and Sanger sequencing. Amino acid analysis provided a biochemical confirmation. Previous cases of Asparagine synthetase deficiency were diagnosed though exome Sequencing. The combination of several techniques (array CGH, sequencing, and biochemical analysis) improves the opportunity to provide accurate diagnosis.
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Affiliation(s)
| | | | | | | | | | | | - Christine Vianey-Saban
- Service de Biochimie & Biologie Moléculaire, UF Maladies Héréditaires du Métabolisme, Hospices Civils de Lyon, F-69500 Bron, France
| | | | | | | | | | - Cécile Acquaviva
- Service de Biochimie & Biologie Moléculaire, UF Maladies Héréditaires du Métabolisme, Hospices Civils de Lyon, F-69500 Bron, France
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16
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Sprute R, Ardicli D, Oguz KK, Malenica-Mandel A, Daimagüler HS, Koy A, Coskun T, Wang H, Topcu M, Cirak S. Clinical outcomes of two patients with a novel pathogenic variant in ASNS: response to asparagine supplementation and review of the literature. Hum Genome Var 2019; 6:24. [PMID: 31123592 PMCID: PMC6531480 DOI: 10.1038/s41439-019-0055-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 03/31/2019] [Accepted: 04/01/2019] [Indexed: 11/09/2022] Open
Abstract
Asparagine synthetase deficiency (ASNSD, OMIM #615574) is a rare autosomal recessive neurometabolic inborn error that leads to severe cognitive impairment. It manifests with microcephaly, intractable seizures, and progressive cerebral atrophy. Currently, there is no established treatment for this condition. In our pediatric cohort, we discovered, by whole-exome sequencing in two siblings from Turkey, a novel homozygous missense mutation in asparagine synthetase at NM_133436.3 (ASNS_v001): c.1108C>T that results in an amino acid exchange p.(Leu370Phe), in the C-terminal domain. After identification of the metabolic defect, treatment with oral asparagine supplementation was attempted in both patients for 24 months. Asparagine supplementation was well tolerated, and no further disease progression was observed during treatment. One of our patients showed mild developmental progress with increased levels of attention and improved nonverbal communication. These results support our hypothesis that asparagine supplementation should be further investigated as a treatment option for ASNSD. We further reviewed all previously reported ASNSD cases with regard for their clinical phenotypes and brain imaging findings to provide an essential knowledge base for rapid diagnosis and future clinical studies.
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Affiliation(s)
- Rosanne Sprute
- 1Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50931 Cologne, Germany.,2Faculty of Medicine and the Faculty of Mathematics and Natural Sciences, Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Didem Ardicli
- 3Department of Pediatric Neurology, Hacettepe University, 06100 Ankara, Turkey
| | - Kader Karli Oguz
- 4Department of Radiology, Hacettepe University, 06100 Ankara, Turkey
| | - Anna Malenica-Mandel
- 1Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50931 Cologne, Germany.,2Faculty of Medicine and the Faculty of Mathematics and Natural Sciences, Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Hülya-Sevcan Daimagüler
- 1Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50931 Cologne, Germany.,2Faculty of Medicine and the Faculty of Mathematics and Natural Sciences, Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Anne Koy
- 1Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50931 Cologne, Germany
| | - Turgay Coskun
- 5Department of Pediatric Metabolism Unit, Hacettepe University, 06100 Ankara, Turkey
| | - Haicui Wang
- 1Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50931 Cologne, Germany.,2Faculty of Medicine and the Faculty of Mathematics and Natural Sciences, Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
| | - Meral Topcu
- 3Department of Pediatric Neurology, Hacettepe University, 06100 Ankara, Turkey
| | - Sebahattin Cirak
- 1Faculty of Medicine and University Hospital Cologne, Department of Pediatrics, University of Cologne, 50931 Cologne, Germany.,2Faculty of Medicine and the Faculty of Mathematics and Natural Sciences, Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany
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17
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Radha Rama Devi A, Naushad SM. Molecular diagnosis of asparagine synthetase (ASNS) deficiency in two Indian families and literature review of 29 ASNS deficient cases. Gene 2019; 704:97-102. [PMID: 30978478 DOI: 10.1016/j.gene.2019.04.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 04/08/2019] [Accepted: 04/08/2019] [Indexed: 11/27/2022]
Abstract
In the current study, we report three cases of Asparagine Synthetase (ASNS) Deficiency from two consanguineous families. Family 1 had two early neonatal deaths due to a novel mutation in the ASNS gene c.788C > T (p.S263F) and both the children presented with microcephaly and one of them had severe intracranial haemorrhage. The proband from the second family was homozygous for c.146G > A (p.R49Q) and manifested myoclonic seizures, developmental delay, coarse hair and diffuse cortical atrophy. Molecular docking studies of both the mutations revealed alteration in the ligand binding site. Till date, 26 mutations were reported in ASNS gene in 29 affected children indicating high degree of genetic heterogeneity and high mortality. Although asparagine depletion is not of diagnostic utility, multiple linear regression model suggested that asparagine levels vary to the extent of 20.6% based on glutamine and aspartate levels and ASNS deficiency results in depletion of asparagine synthesis. ASNS deficiency should be suspected in any neonate with microcephaly and epileptic encephalopathy.
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Affiliation(s)
- Akella Radha Rama Devi
- Rainbow Children's Hospital, Banjara Hills, Road No. 2, Hyderabad, India; Sandor Speciality Diagnostics Pvt Ltd, Banjara Hills, Road No.3, Hyderabad, India.
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18
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Cyst-Peritoneal Shunt for the Treatment of a Progressive Intracerebral Cyst Associated with ASNS Mutation: Case Report and Literature Review. World Neurosurg 2019; 127:1-7. [PMID: 30844524 DOI: 10.1016/j.wneu.2019.02.130] [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] [Received: 11/14/2018] [Revised: 02/19/2019] [Accepted: 02/20/2019] [Indexed: 11/24/2022]
Abstract
BACKGROUND Congenital microcephaly could result from a gene mutation. Asparagine synthetase deficiency, which is caused by the asparagine synthetase (ASNS) mutation, is a rare autosomal-recessive neurometabolic disorder. It is characterized by severe developmental delay, congenital microcephaly, and seizures. CASE DESCRIPTION Here we present the first report on a progressive intracerebral cyst associated with ASNS mutation, which caused neurodevelopmental dysplasia. ASNS mutation was confirmed by whole-exome sequencing and is the most likely reason for the neurodevelopmental dysplasia, which results in microcephaly, refractory seizures, and congenital visual impairment. Antiepileptic drugs have limited therapeutic effect on these epileptic seizures. CONCLUSIONS Although there is no cure for this disorder so far, the huge progressive intracerebral cyst can be cured by a cyst-peritoneal shunt.
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19
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Galada C, Hebbar M, Lewis L, Soans S, Kadavigere R, Srivastava A, Bielas S, Girisha KM, Shukla A. Report of four novel variants in ASNS causing asparagine synthetase deficiency and review of literature. Congenit Anom (Kyoto) 2018; 58:181-182. [PMID: 29405484 PMCID: PMC6338226 DOI: 10.1111/cga.12275] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 12/29/2017] [Accepted: 01/30/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Chelna Galada
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Malavika Hebbar
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Leslie Lewis
- Department of Pediatrics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Santosh Soans
- Department of Paediatrics, A.J. Institute of Medical Sciences and Research Centre, Mangalore, India
| | - Rajagopal Kadavigere
- Department of Radiodiagnosis and Imaging, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Anshika Srivastava
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Stephanie Bielas
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Katta M Girisha
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
| | - Anju Shukla
- Department of Medical Genetics, Kasturba Medical College, Manipal Academy of Higher Education, Manipal, India
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20
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Schleinitz D, Seidel A, Stassart R, Klammt J, Hirrlinger PG, Winkler U, Köhler S, Heiker JT, Schönauer R, Bialek J, Krohn K, Hoffmann K, Kovacs P, Hirrlinger J. Novel Mutations in the Asparagine Synthetase Gene ( ASNS) Associated With Microcephaly. Front Genet 2018; 9:245. [PMID: 30057589 PMCID: PMC6053511 DOI: 10.3389/fgene.2018.00245] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 06/22/2018] [Indexed: 12/30/2022] Open
Abstract
Microcephaly is a devastating condition defined by a small head and small brain compared to the age- and sex-matched population. Mutations in a number of different genes causative for microcephaly have been identified, e.g., MCPH1, WDR62, and ASPM. Recently, mutations in the gene encoding the enzyme asparagine synthetase (ASNS) were associated to microcephaly and so far 24 different mutations in ASNS causing microcephaly have been described. In a family with two affected girls, we identified novel compound heterozygous variants in ASNS (c.1165G > C, p.E389Q and c.601delA, p.M201Wfs∗28). The first mutation (E389Q) is a missense mutation resulting in the replacement of a glutamate residue evolutionary conserved from Escherichia coli to Homo sapiens by glutamine. Protein modeling based on the known crystal structure of ASNS of E. coli predicted a destabilization of the protein by E389Q. The second mutation (p.M201Wfs∗28) results in a premature stop codon after amino acid 227, thereby truncating more than half of the protein. The novel variants expand the growing list of microcephaly causing mutations in ASNS.
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Affiliation(s)
- Dorit Schleinitz
- IFB AdiposityDiseases, Leipzig University Medical Center, University of Leipzig, Leipzig, Germany
| | - Anna Seidel
- Division of Nephrology, Department of Internal Medicine, Leipzig University Medical Center, University of Leipzig, Leipzig, Germany
| | - Ruth Stassart
- Division of Neuropathology, Department of Diagnostic, Leipzig University Medical Center, University of Leipzig, Leipzig, Germany
| | - Jürgen Klammt
- Hospital for Children and Adolescents, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Petra G Hirrlinger
- Medizinisch-Experimentelles Zentrum, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Ulrike Winkler
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Susanne Köhler
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - John T Heiker
- IFB AdiposityDiseases, Leipzig University Medical Center, University of Leipzig, Leipzig, Germany.,Institute of Biochemistry, Faculty of Life Sciences, University of Leipzig, Leipzig, Germany
| | - Ria Schönauer
- Division of Nephrology, Department of Internal Medicine, Leipzig University Medical Center, University of Leipzig, Leipzig, Germany
| | - Joanna Bialek
- Institute of Human Genetics, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Knut Krohn
- Core Unit DNA Technologien, Faculty of Medicine, University of Leipzig, Leipzig, Germany
| | - Katrin Hoffmann
- Institute of Human Genetics, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Peter Kovacs
- IFB AdiposityDiseases, Leipzig University Medical Center, University of Leipzig, Leipzig, Germany
| | - Johannes Hirrlinger
- Carl-Ludwig-Institute for Physiology, Faculty of Medicine, University of Leipzig, Leipzig, Germany.,Department of Neurogenetics, Max-Planck-Institute for Experimental Medicine, Göttingen, Germany
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21
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Sacharow SJ, Dudenhausen EE, Lomelino CL, Rodan L, El Achkar CM, Olson HE, Genetti CA, Agrawal PB, McKenna R, Kilberg MS. Characterization of a novel variant in siblings with Asparagine Synthetase Deficiency. Mol Genet Metab 2018; 123:317-325. [PMID: 29279279 PMCID: PMC5832599 DOI: 10.1016/j.ymgme.2017.12.433] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 12/22/2022]
Abstract
Asparagine Synthetase Deficiency (ASD) is a recently described inborn error of metabolism caused by bi-allelic pathogenic variants in the asparagine synthetase (ASNS) gene. ASD typically presents congenitally with microcephaly and severe, often medically refractory, epilepsy. Development is generally severely affected at birth. Tone is abnormal with axial hypotonia and progressive appendicular spasticity. Hyperekplexia has been reported. Neuroimaging typically demonstrates gyral simplification, abnormal myelination, and progressive cerebral atrophy. The present report describes two siblings from consanguineous parents with a homozygous Arg49Gln variant associated with a milder form of ASD that is characterized by later onset of symptoms. Both siblings had a period of normal development before onset of seizures, and development regression. Primary fibroblast studies of the siblings and their parents document that homozygosity for Arg49Gln blocks cell growth in the absence of extracellular asparagine. Functional studies with these cells suggest no impact of the Arg49Gln variant on basal ASNS mRNA or protein levels, nor on regulation of the gene itself. Molecular modelling of the ASNS protein structure indicates that the Arg49Gln variant lies near the substrate binding site for glutamine. Collectively, the results suggest that the Arg49Gln variant affects the enzymatic function of ASNS. The clinical, cellular, and molecular observations from these siblings expand the known phenotypic spectrum of ASD.
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Affiliation(s)
- Stephanie J Sacharow
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - Elizabeth E Dudenhausen
- Department of Biochemistry & Molecular Biology, Genetics Institute, University of Florida College of Medicine, 1200 Newell Drive, FL 32608, USA
| | - Carrie L Lomelino
- Department of Biochemistry & Molecular Biology, Genetics Institute, University of Florida College of Medicine, 1200 Newell Drive, FL 32608, USA
| | - Lance Rodan
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States; Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - Christelle Moufawad El Achkar
- Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States; Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - Heather E Olson
- Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States; Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - Casie A Genetti
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States; Manton Center for Orphan Disease Research, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - Pankaj B Agrawal
- Division of Genetics and Genomics, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States; Manton Center for Orphan Disease Research, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States; Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, United States
| | - Robert McKenna
- Department of Biochemistry & Molecular Biology, Genetics Institute, University of Florida College of Medicine, 1200 Newell Drive, FL 32608, USA
| | - Michael S Kilberg
- Department of Biochemistry & Molecular Biology, Genetics Institute, University of Florida College of Medicine, 1200 Newell Drive, FL 32608, USA.
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22
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Lomelino CL, Andring JT, McKenna R, Kilberg MS. Asparagine synthetase: Function, structure, and role in disease. J Biol Chem 2017; 292:19952-19958. [PMID: 29084849 PMCID: PMC5723983 DOI: 10.1074/jbc.r117.819060] [Citation(s) in RCA: 159] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Asparagine synthetase (ASNS) converts aspartate and glutamine to asparagine and glutamate in an ATP-dependent reaction. ASNS is present in most, if not all, mammalian organs, but varies widely in basal expression. Human ASNS activity is highly responsive to cellular stress, primarily by increased transcription from a single gene located on chromosome 7. Elevated ASNS protein expression is associated with resistance to asparaginase therapy in childhood acute lymphoblastic leukemia. There is evidence that ASNS expression levels may also be inversely correlated with asparaginase efficacy in certain solid tumors as well. Children with mutations in the ASNS gene exhibit developmental delays, intellectual disability, microcephaly, intractable seizures, and progressive brain atrophy. Thus far, 15 unique mutations in the ASNS gene have been clinically associated with asparagine synthetase deficiency (ASD). Molecular modeling using the Escherichia coli ASNS-B structure has revealed that most of the reported ASD substitutions are located near catalytic sites or within highly conserved regions of the protein. For some ASD patients, fibroblast cell culture studies have eliminated protein and mRNA synthesis or stability as the basis for decreased proliferation.
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Affiliation(s)
- Carrie L Lomelino
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Jacob T Andring
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, College of Medicine, University of Florida, Gainesville, Florida 32610
| | - Michael S Kilberg
- Department of Biochemistry and Molecular Biology, Shands Cancer Center, College of Medicine, University of Florida, Gainesville, Florida 32610.
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