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du Mee DJM, Bak M, Østergaard E, Rasmussen LJ. Mitochondrial dysfunction induced by variation in the non-coding genome - A proposed workflow to improve diagnostics. Mitochondrion 2020; 53:255-259. [PMID: 32497723 DOI: 10.1016/j.mito.2020.05.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/26/2020] [Indexed: 11/18/2022]
Abstract
Mitochondrial disorders are one of the most common inherited metabolic disorders and are caused by variants in nuclear genes or the mitochondrial genome. Additionally, there is a large group of patients displaying clinical symptoms, where the genetic background is unknown. Mitochondrial disorders have a huge variety in their clinical presentation, making diagnostics challenging. Genomes of higher organisms contain around 95% non-protein-coding DNA. Recently, non-protein-coding sequences have been shown to affect gene expression in many cellular processes, including mitochondrial functioning. As these insights are not frequently incorporated in diagnostics we propose a workflow utilizing this knowledge for faster diagnostics of patients lacking a molecular diagnosis.
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Affiliation(s)
- Dorine Jeanne Mariëtte du Mee
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Mads Bak
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Elsebet Østergaard
- Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet and Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Lene Juel Rasmussen
- Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Denmark.
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Ruskin DN, Murphy MI, Slade SL, Masino SA. Ketogenic diet improves behaviors in a maternal immune activation model of autism spectrum disorder. PLoS One 2017; 12:e0171643. [PMID: 28166277 PMCID: PMC5293204 DOI: 10.1371/journal.pone.0171643] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 01/24/2017] [Indexed: 01/31/2023] Open
Abstract
Prenatal factors influence autism spectrum disorder (ASD) incidence in children and can increase ASD symptoms in offspring of animal models. These may include maternal immune activation (MIA) due to viral or bacterial infection during the first trimesters. Unfortunately, regardless of ASD etiology, existing drugs are poorly effective against core symptoms. For nearly a century a ketogenic diet (KD) has been used to treat seizures, and recent insights into mechanisms of ASD and a growing recognition that immune/inflammatory conditions exacerbate ASD risk has increased interest in KD as a treatment for ASD. Here we studied the effects of KD on core ASD symptoms in offspring exposed to MIA. To produce MIA, pregnant C57Bl/6 mice were injected with the viral mimic polyinosinic-polycytidylic acid; after weaning offspring were fed KD or control diet for three weeks. Consistent with an ASD phenotype of a higher incidence in males, control diet-fed MIA male offspring were not social and exhibited high levels of repetitive self-directed behaviors; female offspring were unaffected. However, KD feeding partially or completely reversed all MIA-induced behavioral abnormalities in males; it had no effect on behavior in females. KD-induced metabolic changes of reduced blood glucose and elevated blood ketones were quantified in offspring of both sexes. Prior work from our laboratory and others demonstrate KDs improve relevant behaviors in several ASD models, and here we demonstrate clear benefits of KD in the MIA model of ASD. Together these studies suggest a broad utility for metabolic therapy in improving core ASD symptoms, and support further research to develop and apply ketogenic and/or metabolic strategies in patients with ASD.
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Affiliation(s)
- David N. Ruskin
- Department of Psychology, Neuroscience Program, Trinity College, Hartford, CT, United States of America
- * E-mail:
| | - Michelle I. Murphy
- Department of Psychology, Neuroscience Program, Trinity College, Hartford, CT, United States of America
| | - Sierra L. Slade
- Department of Psychology, Neuroscience Program, Trinity College, Hartford, CT, United States of America
| | - Susan A. Masino
- Department of Psychology, Neuroscience Program, Trinity College, Hartford, CT, United States of America
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Jurecka A, Zikanova M, Kmoch S, Tylki-Szymańska A. Adenylosuccinate lyase deficiency. J Inherit Metab Dis 2015; 38:231-42. [PMID: 25112391 PMCID: PMC4341013 DOI: 10.1007/s10545-014-9755-y] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 07/17/2014] [Accepted: 07/23/2014] [Indexed: 11/26/2022]
Abstract
Adenylosuccinate lyase ADSL) deficiency is a defect of purine metabolism affecting purinosome assembly and reducing metabolite fluxes through purine de novo synthesis and purine nucleotide recycling pathways. Biochemically this defect manifests by the presence in the biologic fluids of two dephosphorylated substrates of ADSL enzyme: succinylaminoimidazole carboxamide riboside (SAICAr) and succinyladenosine (S-Ado). More than 80 individuals with ADSL deficiency have been identified, but incidence of the disease remains unknown. The disorder shows a wide spectrum of symptoms from slowly to rapidly progressing forms. The fatal neonatal form has onset from birth and presents with fatal neonatal encephalopathy with a lack of spontaneous movement, respiratory failure, and intractable seizures resulting in early death within the first weeks of life. Patients with type I (severe form) present with a purely neurologic clinical picture characterized by severe psychomotor retardation, microcephaly, early onset of seizures, and autistic features. A more slowly progressing form has also been described (type II, moderate or mild form), as having later onset, usually within the first years of life, slight to moderate psychomotor retardation and transient contact disturbances. Diagnosis is facilitated by demonstration of SAICAr and S-Ado in extracellular fluids such as plasma, cerebrospinal fluid and/or followed by genomic and/or cDNA sequencing and characterization of mutant proteins. Over 50 ADSL mutations have been identified and their effects on protein biogenesis, structural stability and activity as well as on purinosome assembly were characterized. To date there is no specific and effective therapy for ADSL deficiency.
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Affiliation(s)
- Agnieszka Jurecka
- Department of Genetics, University of Gdańsk, ul. Wita Stwosza 59, 80-308, Gdańsk, Poland,
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van Werkhoven MA, Duley JA, McGown I, Munce T, Freeman JL, Pitt JJ. Early diagnosis of adenylosuccinate lyase deficiency using a high-throughput screening method and a trial of oral S-adenosyl-l-methionine as a treatment method. Dev Med Child Neurol 2013; 55:1060-4. [PMID: 23937257 DOI: 10.1111/dmcn.12244] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/14/2013] [Indexed: 11/30/2022]
Abstract
AIM The aim of this study was to develop a high-throughput urine screening technique for adenylosuccinate lyase (ADSL) deficiency and to evaluate S-adenosyl-l-methionine (SAMe) as a potential treatment for this disorder. METHOD Testing for succinyladenosine (S-Ado), a marker of ADSL deficiency, was incorporated into a screening panel for urine biomarkers for inborn errors of metabolism using electrospray tandem mass spectrometry. Liquid chromatography-mass spectrometry and high-performance liquid chromatography were used to confirm and monitor the response of metabolites to oral SAMe treatment. RESULTS Increased levels of S-Ado were detected in a 3-month-old male infant with hypotonia and seizures. ADSL gene sequencing revealed a previously described c.-49T>C mutation and a novel c.889_891dupAAT mutation, which was likely to disrupt enzyme function. After 9 months of SAMe treatment, there was no clear response evidenced in urine metabolite levels or clinical parameters. INTERPRETATION These results demonstrate proof of the principle for the high-throughput urine screening technique, allowing earlier diagnosis of patients with ADSL deficiency. However, early treatment with SAMe does not appear to be effective in ADSL deficiency. It is suggested that although SAMe treatment may ameliorate purine nucleotide deficiency, it cannot correct metabolic syndromes in which a toxic nucleotide is present, in this case presumed to be succinylaminoimidazole carboxamide ribotide.
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Affiliation(s)
- Michiel A van Werkhoven
- Victorian Clinical Genetics Services, Murdoch Childrens Research Institute, The Royal Children's Hospital, Melbourne, Vic., Australia
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5
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Vliet LK, Wilkinson TG, Duval N, Vacano G, Graham C, Zikánová M, Skopova V, Baresova V, Hnízda A, Kmoch S, Patterson D. Molecular characterization of the AdeI mutant of Chinese hamster ovary cells: a cellular model of adenylosuccinate lyase deficiency. Mol Genet Metab 2011; 102:61-8. [PMID: 20884265 PMCID: PMC3065963 DOI: 10.1016/j.ymgme.2010.08.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 08/30/2010] [Accepted: 08/30/2010] [Indexed: 11/19/2022]
Abstract
Adenylosuccinate lyase (ADSL, E. C. 4.3.2.2) carries out two non-sequential steps in de novo AMP synthesis, the conversion of succinylaminoimidazole carboxamide ribotide (SAICAR) to aminoimidazolecarboxamide ribotide (AICAR) and the conversion of succinyl AMP (AMPS) to AMP. In humans, mutations in ADSL lead to an inborn error of metabolism originally characterized by developmental delay, often with autistic features. There is no effective treatment for ADSL deficiency. Hypotheses regarding the pathogenesis include toxicity of high levels of SAICAR, AMPS, or their metabolites, deficiency of the de novo purine biosynthetic pathway, or lack of a completely functional purine cycle in muscle and brain. One important approach to understand ADSL deficiency is to develop cell culture models that allow investigation of the properties of ADSL mutants and the consequences of ADSL deficiency at the cellular level. We previously reported the isolation and initial characterization of mutants of Chinese hamster ovary (CHO-K1) cells (AdeI) that lack detectable ADSL activity, accumulate SAICAR and AMPS, and require adenine for growth. Here we report the cDNA sequences of ADSL from CHO-K1 and AdeI cells and describe a mutation resulting in an alanine to valine amino acid substitution at position 291 (A291V) in AdeI ADSL. This substitution lies in the "signature sequence" of ADSL, inactivates the enzyme, and validates AdeI as a cellular model of ADSL deficiency.
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Affiliation(s)
- Lydia K. Vliet
- Eleanor Roosevelt Institute and Department of Biological Sciences, University of Denver, 2101 E. Wesley Avenue, Denver, CO, 80208
| | - Terry G. Wilkinson
- Eleanor Roosevelt Institute and Department of Biological Sciences, University of Denver, 2101 E. Wesley Avenue, Denver, CO, 80208
| | - Nathan Duval
- Eleanor Roosevelt Institute and Department of Biological Sciences, University of Denver, 2101 E. Wesley Avenue, Denver, CO, 80208
| | - Guido Vacano
- Eleanor Roosevelt Institute and Department of Biological Sciences, University of Denver, 2101 E. Wesley Avenue, Denver, CO, 80208
| | - Christine Graham
- Eleanor Roosevelt Institute and Department of Biological Sciences, University of Denver, 2101 E. Wesley Avenue, Denver, CO, 80208
| | - Marie Zikánová
- Center for Applied Genomics, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
- Institute of Inherited Metabolic Disorders, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
| | - Vaclava Skopova
- Center for Applied Genomics, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
- Institute of Inherited Metabolic Disorders, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
| | - Veronika Baresova
- Center for Applied Genomics, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
- Institute of Inherited Metabolic Disorders, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
| | - Aleš Hnízda
- Institute of Inherited Metabolic Disorders, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
| | - Stanislav Kmoch
- Center for Applied Genomics, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
- Institute of Inherited Metabolic Disorders, Charles University in Prague, First Faculty of Medicine, Ke Karlovu 2, 128 00 Prague 2, Czech Republic
| | - David Patterson
- Eleanor Roosevelt Institute and Department of Biological Sciences, University of Denver, 2101 E. Wesley Avenue, Denver, CO, 80208
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Chen BC, McGown IN, Thong MK, Pitt J, Yunus ZM, Khoo TB, Ngu LH, Duley JA. Adenylosuccinate lyase deficiency in a Malaysian patient, with novel adenylosuccinate lyase gene mutations. J Inherit Metab Dis 2010; 33 Suppl 3:S159-62. [PMID: 20177786 DOI: 10.1007/s10545-010-9056-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Revised: 01/08/2010] [Accepted: 01/18/2010] [Indexed: 10/19/2022]
Abstract
Most cases of adenylosuccinate lyase (ADSL OMIM 103050) deficiency reported to date are confined to the various European ethnic groups. We report on the first Malaysian case of ADSL deficiency, which appears also to be the first reported Asian case. The case was diagnosed among a cohort of 450 patients with clinical features of psychomotor retardation, global developmental delay, seizures, microcephaly and/or autistic behaviour. The patient presented with frequent convulsions and severe myoclonic jerk within the first few days of life and severe psychomotor retardation. The high performance liquid chromatography (HPLC) profile of the urine revealed the characteristic biochemical markers of succinyladenosine (S-Ado) and succinyl-aminoimidazole carboximide riboside (SAICAr). The urinary S-Ado/SAICAr ratio was found to be 1.02 (type I ADSL deficiency). The patient was compound heterozygous for two novel mutations, c.445C > G (p.R149G) and c.774_778insG (p.A260GfsX24).
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Affiliation(s)
- Bee Chin Chen
- Biochemical Genetic Unit, Department of Genetics, Kuala Lumpur Hospital, Jalan Pahang 50586, Malaysia.
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Lundy CT, Jungbluth H, Pohl KRE, Siddiqui A, Marinaki AM, Mundy H, Champion MP. Adenylosuccinate lyase deficiency in the United Kingdom pediatric population: first three cases. Pediatr Neurol 2010; 43:351-4. [PMID: 20933180 DOI: 10.1016/j.pediatrneurol.2010.06.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Accepted: 06/02/2010] [Indexed: 11/24/2022]
Abstract
Adenylosuccinate lyase deficiency is an autosomal recessive disorder of purine metabolism resulting from mutations in the ADSL gene on chromosome subband 22q13.1 and associated with a wide range of clinical manifestations. Although there is currently no effective treatment of ADSL deficiency, recognition of the condition is important, because prenatal genetic diagnosis can be offered to affected families. Reported here are the cases of the only three children diagnosed to date in the United Kingdom with adenylosuccinate lyase deficiency, to further delineate the clinical phenotype and to raise awareness of this disorder.
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Affiliation(s)
- Claire T Lundy
- Department of Paediatric Neurology, Evelina Children's Hospital, Guy's and St Thomas' NHS Foundation Trust, St Thomas' Hospital, London, UK
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8
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Masino SA, Kawamura M, Wasser CD, Wasser CA, Pomeroy LT, Ruskin DN. Adenosine, ketogenic diet and epilepsy: the emerging therapeutic relationship between metabolism and brain activity. Curr Neuropharmacol 2010; 7:257-68. [PMID: 20190967 PMCID: PMC2769009 DOI: 10.2174/157015909789152164] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 05/01/2009] [Accepted: 05/06/2009] [Indexed: 12/12/2022] Open
Abstract
For many years the neuromodulator adenosine has been recognized as an endogenous anticonvulsant molecule and termed a “retaliatory metabolite.” As the core molecule of ATP, adenosine forms a unique link between cell energy and neuronal excitability. In parallel, a ketogenic (high-fat, low-carbohydrate) diet is a metabolic therapy that influences neuronal activity significantly, and ketogenic diets have been used successfully to treat medically-refractory epilepsy, particularly in children, for decades. To date the key neural mechanisms underlying the success of dietary therapy are unclear, hindering development of analogous pharmacological solutions. Similarly, adenosine receptor–based therapies for epilepsy and myriad other disorders remain elusive. In this review we explore the physiological regulation of adenosine as an anticonvulsant strategy and suggest a critical role for adenosine in the success of ketogenic diet therapy for epilepsy. While the current focus is on the regulation of adenosine, ketogenic metabolism and epilepsy, the therapeutic implications extend to acute and chronic neurological disorders as diverse as brain injury, inflammatory and neuropathic pain, autism and hyperdopaminergic disorders. Emerging evidence for broad clinical relevance of the metabolic regulation of adenosine will be discussed.
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Affiliation(s)
- S A Masino
- Psychology Department, Trinity College, 300 Summit St., Hartford, CT, USA.
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Shu JT, Bao WB, Zhang XY, Ji CJ, Han W, Chen KW. Combined effect of mutations in ADSL and GARS-AIRS-GART genes on IMP content in chickens. Br Poult Sci 2010; 50:680-6. [PMID: 19946821 DOI: 10.1080/00071660903391709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
1. The objective of this study was to investigate the effect of ADSL gene, GARS-AIRS-GART gene and their combination genotype on inosine monophosphate content (IMP) in chicken. 2. The chicken breeds used for this study were Recessive White chicken (RW, Jiang-13 strain of white Plymouth Rock) and preserved population of 4 Chinese native chicken breeds, including Silkies, Baier, Tibetan and Xiaoshan. 3. The primers for exon 2 in ADSL gene and 5'UTR region in GARS-AIRS-GART gene were designed and the single nucleotide polymorphisms (SNPs) were detected by PCR-SSCP and DNA sequencing. 4. Two SNPs were detected, C/T substitution at position 3484 in exon 2 of ADSL gene, which was a silent mutation, and C/T point mutation at position -179 in 5'UTR region of GARS-AIRS-GART gene. In ADSL gene, individuals with TT genotype had significantly higher IMP content than CT and CC genotype individuals. No significant difference was observed between CT and CC genotypes. Similar results were obtained for GARS-AIRS-GART gene. The combination of genotypes ADSL and GARS-AIRS-GART genes also had a significant effect on IMP content. Individuals with TTTT genotype had the highest muscle IMP content, while individuals with CCCT genotype had the lowest. 4. We putatively drew the conclusion that the SNPs in these two genes, as well as the combination genotypes, could be used as potential molecular markers for meat quality in chicken.
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Affiliation(s)
- J T Shu
- Institute of Poultry Science, Chinese Academy of Agricultural Sciences, Yangzhou, 225009, Jiangsu, PR China
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10
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Patterson D. Molecular genetic analysis of Down syndrome. Hum Genet 2009; 126:195-214. [PMID: 19526251 DOI: 10.1007/s00439-009-0696-8] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Accepted: 05/29/2009] [Indexed: 12/18/2022]
Abstract
Down syndrome (DS) is caused by trisomy of all or part of human chromosome 21 (HSA21) and is the most common genetic cause of significant intellectual disability. In addition to intellectual disability, many other health problems, such as congenital heart disease, Alzheimer's disease, leukemia, hypotonia, motor disorders, and various physical anomalies occur at an elevated frequency in people with DS. On the other hand, people with DS seem to be at a decreased risk of certain cancers and perhaps of atherosclerosis. There is wide variability in the phenotypes associated with DS. Although ultimately the phenotypes of DS must be due to trisomy of HSA21, the genetic mechanisms by which the phenotypes arise are not understood. The recent recognition that there are many genetically active elements that do not encode proteins makes the situation more complex. Additional complexity may exist due to possible epigenetic changes that may act differently in DS. Numerous mouse models with features reminiscent of those seen in individuals with DS have been produced and studied in some depth, and these have added considerable insight into possible genetic mechanisms behind some of the phenotypes. These mouse models allow experimental approaches, including attempts at therapy, that are not possible in humans. Progress in understanding the genetic mechanisms by which trisomy of HSA21 leads to DS is the subject of this review.
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Affiliation(s)
- David Patterson
- Eleanor Roosevelt Institute, University of Denver, 2101 E. Wesley Avenue, Denver, CO 80208-6600, USA.
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Mouchegh K, Zikánová M, Hoffmann GF, Kretzschmar B, Kühn T, Mildenberger E, Stoltenburg-Didinger G, Krijt J, Dvoráková L, Honzík T, Zeman J, Kmoch S, Rossi R. Lethal fetal and early neonatal presentation of adenylosuccinate lyase deficiency: observation of 6 patients in 4 families. J Pediatr 2007; 150:57-61.e2. [PMID: 17188615 DOI: 10.1016/j.jpeds.2006.09.027] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2006] [Revised: 07/10/2006] [Accepted: 09/08/2006] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To characterize a new lethal fetal and early postnatal variant of adenylosuccinate lyase (ADSL) deficiency. STUDY DESIGN This was a retrospective analysis of 6 patients with very early presentation of ADSL deficiency. RESULTS Most of the 6 patients had impaired intrauterine growth, microcephaly, fetal hypokinesia, and a lack of fetal heart rate variability. Postnatally, they shared severe muscular hypotonia necessitating mechanical ventilation, intractable seizures, and early death. All 6 patients had biochemical evidence of severe (type 1) disease and low residual ADSL activities. All were compound heterozygous for mutations that, based on expression studies, have a pronounced effect on ADSL activity and/or stability. CONCLUSIONS ADSL deficiency may present with prenatal growth restriction, fetal and neonatal hypokinesia, and rapidly fatal neonatal encephalopathy. This clinical presentation is associated with genotypes resulting in very low residual enzyme activity.
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Borck G, Zarhrate M, Cluzeau C, Bal E, Bonnefont JP, Munnich A, Cormier-Daire V, Colleaux L. Father-to-daughter transmission of Cornelia de Lange syndrome caused by a mutation in the 5' untranslated region of the NIPBL Gene. Hum Mutat 2006; 27:731-5. [PMID: 16799922 DOI: 10.1002/humu.20380] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Cornelia de Lange syndrome (CdLS; also called Brachmann de Lange syndrome) is a developmental disorder characterized by typical facial dysmorphism, growth and mental retardation, microcephaly, and various malformations. Mutations in the NIPBL gene have been identified in approximately 40% of reported cases, suggesting either genetic heterogeneity or that some NIPBL mutations are not detected by current screening strategies. We screened a cohort of 21 patients with no previously identified NIPBL anomaly for mutations in the 5' untranslated region (5'UTR) and the proximal promoter of the NIPBL gene. We identified a heterozygous deletion-insertion mutation in exon 1, 321 nucleotides upstream of the translation initiation codon (c.-321_-320delCCinsA) in one affected girl and her mildly affected father. This mutation altered highly conserved nucleotides, was not found in 400 control alleles, arose de novo in the father, and cosegregated with the disease in the family. Using real-time quantitative PCR, we showed that NIPBL mRNA expression was lowered in patients' lymphocytes compared to control samples. Finally, we showed that, when subcloned into a luciferase reporter vector, the mutation leads to a significant reduction of reporter gene activity. Our results demonstrate that mutations in the 5' noncoding region of the NIPBL gene can be involved in the pathogenesis of CdLS. Mutations affecting this region of the gene might be associated with a milder phenotype.
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Affiliation(s)
- Guntram Borck
- INSERM U781 and Département de Génétique, Hôpital Necker-Enfants Malades, Paris, France.
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13
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Blesa JR, Hernández-Yago J. Distinct functional contributions of 2 GABP–NRF-2 recognition sites within the context of the human TOMM70 promoter. Biochem Cell Biol 2006; 84:813-22. [PMID: 17167546 DOI: 10.1139/o06-064] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
TOMM70 is a subunit of the outer mitochondrial membrane translocase that plays a major role as a receptor of hydrophobic preproteins targeted to mitochondria. We have previously reported 2 binding sites for the transcription factor GABP–NRF-2 in the promoter region of the human TOMM70 gene that are important in activating transcription. To assess the functionality and actual role of these sites, chromatin immunoprecipitation, site-directed mutagenesis, and electrophoretic mobility shift assays were carried out. We conclude that GABP–NRF-2 binds in vivo to the TOMM70 promoter, and that the 2 GABP–NRF-2 binding sites of the promoter have different functional contributions in promoting TOMM70 expression. Evidence is provided that they work in an additive manner as single sites.
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Affiliation(s)
- José R Blesa
- Fundación Centro de Investigación Príncipe Felipe, Av. Autopista del Saler 16-3, 46013 Valencia, Spain
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14
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Sivendran S, Patterson D, Spiegel E, McGown I, Cowley D, Colman RF. Two novel mutant human adenylosuccinate lyases (ASLs) associated with autism and characterization of the equivalent mutant Bacillus subtilis ASL. J Biol Chem 2004; 279:53789-97. [PMID: 15471876 DOI: 10.1074/jbc.m409974200] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An Australian patient with autism was found to be heterozygous for two mutations in the gene encoding adenylosuccinate lyase (ASL), resulting in the protein mutations E80D and D87E. The patient's mother carried only the E80D mutation. The equivalent positions are 62 and 69 in Bacillus subtilis ASL. Although both human and B. subtilis enzymes normally have Asp at position 87 (or 69), the B. subtilis ASL has Ile and Asp at 62 and 65, respectively, whereas human ASL has Glu and Arg at the equivalent positions. We have constructed, expressed, and purified the double mutant I62E/D65R as a "humanized" normal B. subtilis enzyme to compare with enzymes with a single mutation at position 62 (I62D/D65R), at position 69 (I62E/D65R/D69E), or at both positions (I62D/D65R/D69E). V(max) for conversion of adenylosuccinate to AMP and fumarate is 0.57 micromol/min/mg for I62E/D65R, 0.064 micromol/min/mg for I62D/D65R, 0.27 micromol/min/mg for I62E/D65R/D69E, and 0.069 micromol/min/mg for I62D/D65R/D69E. The K(m) for adenylosuccinate is elevated in the X62D mutants, and I62D/D65R is the least stable of these ASLs at 37 degrees C. The CD spectra of mutant and wild type enzymes are similar; thus, there are no appreciable structural changes. Clearly the Asp(62) causes the most drastic effect on ASL function, whereas the Glu(69) mutation produces only modest change. These results emphasize the importance of expanding tests for ASL deficiency to individuals with developmental delay of any severity, including individuals with autistic spectrum disorder. This study further demonstrates the usefulness of the B. subtilis ASL as a model to mimic the defective enzyme in ASL deficiency.
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Affiliation(s)
- Sharmila Sivendran
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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