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Kunová N, Havalová H, Ondrovičová G, Stojkovičová B, Bauer JA, Bauerová-Hlinková V, Pevala V, Kutejová E. Mitochondrial Processing Peptidases-Structure, Function and the Role in Human Diseases. Int J Mol Sci 2022; 23:1297. [PMID: 35163221 PMCID: PMC8835746 DOI: 10.3390/ijms23031297] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 12/21/2022] Open
Abstract
Mitochondrial proteins are encoded by both nuclear and mitochondrial DNA. While some of the essential subunits of the oxidative phosphorylation (OXPHOS) complexes responsible for cellular ATP production are synthesized directly in the mitochondria, most mitochondrial proteins are first translated in the cytosol and then imported into the organelle using a sophisticated transport system. These proteins are directed mainly by targeting presequences at their N-termini. These presequences need to be cleaved to allow the proper folding and assembly of the pre-proteins into functional protein complexes. In the mitochondria, the presequences are removed by several processing peptidases, including the mitochondrial processing peptidase (MPP), the inner membrane processing peptidase (IMP), the inter-membrane processing peptidase (MIP), and the mitochondrial rhomboid protease (Pcp1/PARL). Their proper functioning is essential for mitochondrial homeostasis as the disruption of any of them is lethal in yeast and severely impacts the lifespan and survival in humans. In this review, we focus on characterizing the structure, function, and substrate specificities of mitochondrial processing peptidases, as well as the connection of their malfunctions to severe human diseases.
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Affiliation(s)
| | | | | | | | | | | | | | - Eva Kutejová
- Department of Biochemistry and Protein Structure, Institute of Molecular Biology, Slovak Academy of Sciences, Dúbravská Cesta 21, 845 51 Bratislava, Slovakia; (H.H.); (G.O.); (B.S.); (J.A.B.); (V.B.-H.); (V.P.)
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2
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Levy AM, Paschou P, Tümer Z. Candidate Genes and Pathways Associated with Gilles de la Tourette Syndrome-Where Are We? Genes (Basel) 2021; 12:1321. [PMID: 34573303 PMCID: PMC8468358 DOI: 10.3390/genes12091321] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/05/2021] [Accepted: 08/25/2021] [Indexed: 12/21/2022] Open
Abstract
Gilles de la Tourette syndrome (GTS) is a childhood-onset neurodevelopmental and -psychiatric tic-disorder of complex etiology which is often comorbid with obsessive-compulsive disorder (OCD) and/or attention deficit hyperactivity disorder (ADHD). Twin and family studies of GTS individuals have shown a high level of heritability suggesting, that genetic risk factors play an important role in disease etiology. However, the identification of major GTS susceptibility genes has been challenging, presumably due to the complex interplay between several genetic factors and environmental influences, low penetrance of each individual factor, genetic diversity in populations, and the presence of comorbid disorders. To understand the genetic components of GTS etiopathology, we conducted an extensive review of the literature, compiling the candidate susceptibility genes identified through various genetic approaches. Even though several strong candidate genes have hitherto been identified, none of these have turned out to be major susceptibility genes yet.
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Affiliation(s)
- Amanda M. Levy
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, 2600 Glostrup, Denmark;
| | - Peristera Paschou
- Department of Molecular Biology and Genetics, Democritus University of Thrace, 68100 Alexandroupolis, Greece;
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Zeynep Tümer
- Kennedy Center, Department of Clinical Genetics, Copenhagen University Hospital, Rigshospitalet, 2600 Glostrup, Denmark;
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
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3
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Vasilyev SA, Skryabin NA, Kashevarova AA, Tolmacheva EN, Savchenko RR, Vasilyeva OY, Lopatkina ME, Zarubin AA, Fishman VS, Belyaeva EO, Filippova MO, Shorina AR, Maslennikov AB, Shestovskikh OL, Gayner TA, Čulić V, Vulić R, Nazarenko LP, Lebedev IN. Differential DNA Methylation of the IMMP2L Gene in Families with Maternally Inherited 7q31.1 Microdeletions is Associated with Intellectual Disability and Developmental Delay. Cytogenet Genome Res 2021; 161:105-119. [PMID: 33849037 DOI: 10.1159/000514491] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 01/18/2021] [Indexed: 11/19/2022] Open
Abstract
Most copy number variations (CNVs) in the human genome display incomplete penetrance with unknown underlying mechanisms. One such mechanism may be epigenetic modification, particularly DNA methylation. The IMMP2L gene is located in a critical region for autism susceptibility on chromosome 7q (AUTS1). The level of DNA methylation was assessed by bisulfite sequencing of 87 CpG sites in the IMMP2L gene in 3 families with maternally inherited 7q31.1 microdeletions affecting the IMMP2L gene alone. Bisulfite sequencing revealed comparable levels of DNA methylation in the probands, healthy siblings without microdeletions, and their fathers. In contrast, a reduced DNA methylation index and increased IMMP2L expression were observed in lymphocytes from the healthy mothers compared with the probands. A number of genes were upregulated in the healthy mothers compared to controls and downregulated in probands compared to mothers. These genes were enriched in components of the ribosome and electron transport chain, as well as oxidative phosphorylation and various degenerative conditions. Differential expression in probands and mothers with IMMP2L deletions relative to controls may be due to compensatory processes in healthy mothers with IMMP2L deletions and disturbances of these processes in probands with intellectual disability. The results suggest a possible partial compensation for IMMP2L gene haploinsufficiency in healthy mothers with the 7q31.1 microdeletion by reducing the DNA methylation level. Differential DNA methylation of intragenic CpG sites may affect the phenotypic manifestation of CNVs and explain the incomplete penetrance of chromosomal microdeletions.
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Affiliation(s)
- Stanislav A Vasilyev
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Nikolay A Skryabin
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Anna A Kashevarova
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Ekaterina N Tolmacheva
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Renata R Savchenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Oksana Yu Vasilyeva
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Maria E Lopatkina
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Alexei A Zarubin
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Veniamin S Fishman
- Institute of Cytology and Genetics, SB RAS, Novosibirsk, Russian Federation
| | - Elena O Belyaeva
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Miroslava O Filippova
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Asia R Shorina
- Novosibirsk City Clinical Hospital, Novosibirsk, Russian Federation
| | | | | | - Tatyana A Gayner
- Group of Companies "Center of New Medical Technologies,", Novosibirsk, Russian Federation.,Institute of Chemical Biology and Fundamental Medicine, SB RAS, Novosibirsk, Russian Federation
| | - Vida Čulić
- Gynecology and Obstetrics Private Outpatient Clinic, Split, Croatia
| | - Robert Vulić
- Gynecology and Obstetrics Private Outpatient Clinic, Split, Croatia
| | - Lyudmila P Nazarenko
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
| | - Igor N Lebedev
- Research Institute of Medical Genetics, Tomsk National Research Medical Center, Tomsk, Russian Federation
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4
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Gomez-Fabra Gala M, Vögtle FN. Mitochondrial proteases in human diseases. FEBS Lett 2021; 595:1205-1222. [PMID: 33453058 DOI: 10.1002/1873-3468.14039] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022]
Abstract
Mitochondria contain more than 1000 different proteins, including several proteolytic enzymes. These mitochondrial proteases form a complex system that performs limited and terminal proteolysis to build the mitochondrial proteome, maintain, and control its functions or degrade mitochondrial proteins and peptides. During protein biogenesis, presequence proteases cleave and degrade mitochondrial targeting signals to obtain mature functional proteins. Processing by proteases also exerts a regulatory role in modulation of mitochondrial functions and quality control enzymes degrade misfolded, aged, or superfluous proteins. Depending on their different functions and substrates, defects in mitochondrial proteases can affect the majority of the mitochondrial proteome or only a single protein. Consequently, mutations in mitochondrial proteases have been linked to several human diseases. This review gives an overview of the components and functions of the mitochondrial proteolytic machinery and highlights the pathological consequences of dysfunctional mitochondrial protein processing and turnover.
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Affiliation(s)
- Maria Gomez-Fabra Gala
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Germany.,Faculty of Biology, University of Freiburg, Germany.,Spemann Graduate School of Biology and Medicine, University of Freiburg, Germany
| | - Friederike-Nora Vögtle
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, Germany.,CIBSS-Centre for Integrative Biological Signalling Studies, University of Freiburg, Germany
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5
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Qaiser F, Yin Y, Mervis CB, Morris CA, Klein-Tasman BP, Tam E, Osborne LR, Yuen RKC. Rare and low frequency genomic variants impacting neuronal functions modify the Dup7q11.23 phenotype. Orphanet J Rare Dis 2021; 16:6. [PMID: 33407644 PMCID: PMC7788915 DOI: 10.1186/s13023-020-01648-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 12/14/2020] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND 7q11.23 duplication (Dup7) is one of the most frequent recurrent copy number variants (CNVs) in individuals with autism spectrum disorder (ASD), but based on gold-standard assessments, only 19% of Dup7 carriers have ASD, suggesting that additional genetic factors are necessary to manifest the ASD phenotype. To assess the contribution of additional genetic variants to the Dup7 phenotype, we conducted whole-genome sequencing analysis of 20 Dup7 carriers: nine with ASD (Dup7-ASD) and 11 without ASD (Dup7-non-ASD). RESULTS We identified three rare variants of potential clinical relevance for ASD: a 1q21.1 microdeletion (Dup7-non-ASD) and two deletions which disrupted IMMP2L (one Dup7-ASD, one Dup7-non-ASD). There were no significant differences in gene-set or pathway variant burden between the Dup7-ASD and Dup7-non-ASD groups. However, overall intellectual ability negatively correlated with the number of rare loss-of-function variants present in nervous system development and membrane component pathways, and adaptive behaviour standard scores negatively correlated with the number of low-frequency likely-damaging missense variants found in genes expressed in the prenatal human brain. ASD severity positively correlated with the number of low frequency loss-of-function variants impacting genes expressed at low levels in the brain, and genes with a low level of intolerance. CONCLUSIONS Our study suggests that in the presence of the same pathogenic Dup7 variant, rare and low frequency genetic variants act additively to contribute to components of the overall Dup7 phenotype.
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Affiliation(s)
- Farah Qaiser
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
- Genetics & Genome Biology Program, The Hospital for Sick Children, 686 Bay St., Toronto, ON M5G 0A4 Canada
| | - Yue Yin
- Genetics & Genome Biology Program, The Hospital for Sick Children, 686 Bay St., Toronto, ON M5G 0A4 Canada
| | - Carolyn B. Mervis
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, KY USA
| | - Colleen A. Morris
- Department of Pediatrics, UNLV School of Medicine, Las Vegas, NV USA
| | | | - Elaine Tam
- Department of Medicine, University of Toronto, Toronto, ON Canada
| | - Lucy R. Osborne
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
- Department of Medicine, University of Toronto, Toronto, ON Canada
| | - Ryan K. C. Yuen
- Department of Molecular Genetics, University of Toronto, Toronto, ON Canada
- Genetics & Genome Biology Program, The Hospital for Sick Children, 686 Bay St., Toronto, ON M5G 0A4 Canada
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Agarwala S, Veerappa AM, Ramachandra NB. Identification of primary copy number variations reveal enrichment of Calcium, and MAPK pathways sensitizing secondary sites for autism. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2020. [DOI: 10.1186/s43042-020-00091-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Autism is a neurodevelopmental condition with genetic heterogeneity. It is characterized by difficulties in reciprocal social interactions with strong repetitive behaviors and stereotyped interests. Copy number variations (CNVs) are genomic structural variations altering the genomic structure either by duplication or deletion. De novo or inherited CNVs are found in 5–10% of autistic subjects with a size range of few kilobases to several megabases. CNVs predispose humans to various diseases by altering gene regulation, generation of chimeric genes, and disruption of the coding region or through position effect. Although, CNVs are not the initiating event in pathogenesis; additional preceding mutations might be essential for disease manifestation. The present study is aimed to identify the primary CNVs responsible for autism susceptibility in healthy cohorts to sensitize secondary-hits. In the current investigation, primary-hit autism gene CNVs are characterized in 1715 healthy cohorts of varying ethnicities across 12 populations using Affymetrix high-resolution array study. Thirty-eight individuals from twelve families residing in Karnataka, India, with the age group of 13–73 years are included for the comparative CNV analysis. The findings are validated against global 179 autism whole-exome sequence datasets derived from Simons Simplex Collection. These datasets are deposited at the Simons Foundation Autism Research Initiative (SFARI) database.
Results
The study revealed that 34.8% of the subjects carried 2% primary-hit CNV burden with 73 singleton-autism genes in different clusters. Of these, three conserved CNV breakpoints were identified with ARHGAP11B, DUSP22, and CHRNA7 as the target genes across 12 populations. Enrichment analysis of the population-specific autism genes revealed two signaling pathways—calcium and mitogen-activated protein kinases (MAPK) in the CNV identified regions. These impaired pathways affected the downstream cascades of neuronal function and physiology, leading to autism behavior. The pathway analysis of enriched genes unravelled complex protein interaction networks, which sensitized secondary sites for autism. Further, the identification of miRNA targets associated with autism gene CNVs added severity to the condition.
Conclusion
These findings contribute to an atlas of primary-hit genes to detect autism susceptibility in healthy cohorts, indicating their impact on secondary sites for manifestation.
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Yoon SH, Choi J, Lee WJ, Do JT. Genetic and Epigenetic Etiology Underlying Autism Spectrum Disorder. J Clin Med 2020; 9:E966. [PMID: 32244359 PMCID: PMC7230567 DOI: 10.3390/jcm9040966] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/28/2020] [Accepted: 03/28/2020] [Indexed: 12/19/2022] Open
Abstract
Autism spectrum disorder (ASD) is a pervasive neurodevelopmental disorder characterized by difficulties in social interaction, language development delays, repeated body movements, and markedly deteriorated activities and interests. Environmental factors, such as viral infection, parental age, and zinc deficiency, can be plausible contributors to ASD susceptibility. As ASD is highly heritable, genetic risk factors involved in neurodevelopment, neural communication, and social interaction provide important clues in explaining the etiology of ASD. Accumulated evidence also shows an important role of epigenetic factors, such as DNA methylation, histone modification, and noncoding RNA, in ASD etiology. In this review, we compiled the research published to date and described the genetic and epigenetic epidemiology together with environmental risk factors underlying the etiology of the different phenotypes of ASD.
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Affiliation(s)
| | | | | | - Jeong Tae Do
- Department of Stem Cell and Regenerative Biotechnology, KU Institute of Technology, Konkuk University, Seoul 05029, Korea; (S.H.Y.); (J.C.); (W.J.L.)
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8
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Kreilaus F, Chesworth R, Eapen V, Clarke R, Karl T. First behavioural assessment of a novel Immp2l knockdown mouse model with relevance for Gilles de la Tourette syndrome and Autism spectrum disorder. Behav Brain Res 2019; 374:112057. [PMID: 31233820 DOI: 10.1016/j.bbr.2019.112057] [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: 03/26/2019] [Revised: 06/20/2019] [Accepted: 06/20/2019] [Indexed: 11/26/2022]
Abstract
Gilles de la Tourette syndrome (GTS) is a neurodevelopmental disorder, which shares some clinical features with Autism spectrum disorder (ASD). The genetic factors relevant to the development of both disorders are yet to be fully understood, however, some genetic association studies have identified inner mitochondrial membrane peptidase subunit 2 (IMMP2L) as a potential risk gene for both GTS and ASD. The impact of Immp2l deficiency on behavioural domains is currently unknown. A new genetic mouse model for Immp2l was developed. Adult heterozygous (HET) and homozygous (HOMO) Immp2l knockdown (Immp2l KD) mice of both sexes were compared to wild type-like (WT) littermates in the open field (OF), social interaction, novel object recognition, marble burying, and prepulse inhibition (PPI). The effect of acute dexamphetamine (2 mg/kg) on OF behaviour was also determined. OF locomotion was significantly higher in HET compared to HOMO male littermates. Male and female HOMO mice were much more sensitive to the locomotor-stimulating effects of dexamphetamine (DEX), whereas only HOMO males exhibited significant increased DEX-induced OF exploration compared to control groups. HOMO females failed to habituate to an acoustic startle stimulus. Furthermore, compared to HOMO females, HET females showed reduced social interaction, and a similar trend was seen in HET males. The Immp2l KD mouse model possesses moderate face validity for preclinical research into GTS and ASD, in particular as dysfunctional dopaminergic neurotransmission appears to be one mechanism leading to disease presentation. The sex-dependent differences observed in most findings reinforce the strong influence of sex in the pathophysiology of GTS and ASD.
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Affiliation(s)
- Fabian Kreilaus
- School of Medicine, Western Sydney University, NSW 2560, Australia
| | - Rose Chesworth
- School of Medicine, Western Sydney University, NSW 2560, Australia
| | - Valsamma Eapen
- School of Psychiatry, Faculty of Medicine and Ingham Institute, University of New South Wales, NSW, 2052, Australia
| | - Raymond Clarke
- School of Psychiatry, Faculty of Medicine and Ingham Institute, University of New South Wales, NSW, 2052, Australia.
| | - Tim Karl
- School of Medicine, Western Sydney University, NSW 2560, Australia; Neuroscience Research Australia (NeuRA), NSW, 2031, Australia; School of Medical Sciences, University of New South Wales, NSW, 2052, Australia.
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Rose S, Niyazov DM, Rossignol DA, Goldenthal M, Kahler SG, Frye RE. Clinical and Molecular Characteristics of Mitochondrial Dysfunction in Autism Spectrum Disorder. Mol Diagn Ther 2018; 22:571-593. [PMID: 30039193 PMCID: PMC6132446 DOI: 10.1007/s40291-018-0352-x] [Citation(s) in RCA: 123] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Autism spectrum disorder (ASD) affects ~ 2% of children in the United States. The etiology of ASD likely involves environmental factors triggering physiological abnormalities in genetically sensitive individuals. One of these major physiological abnormalities is mitochondrial dysfunction, which may affect a significant subset of children with ASD. Here we systematically review the literature on human studies of mitochondrial dysfunction related to ASD. Clinical aspects of mitochondrial dysfunction in ASD include unusual neurodevelopmental regression, especially if triggered by an inflammatory event, gastrointestinal symptoms, seizures, motor delays, fatigue and lethargy. Traditional biomarkers of mitochondrial disease are widely reported to be abnormal in ASD, but appear non-specific. Newer biomarkers include buccal cell enzymology, biomarkers of fatty acid metabolism, non-mitochondrial enzyme function, apoptosis markers and mitochondrial antibodies. Many genetic abnormalities are associated with mitochondrial dysfunction in ASD, including chromosomal abnormalities, mitochondrial DNA mutations and large-scale deletions, and mutations in both mitochondrial and non-mitochondrial nuclear genes. Mitochondrial dysfunction has been described in immune and buccal cells, fibroblasts, muscle and gastrointestinal tissue and the brains of individuals with ASD. Several environmental factors, including toxicants, microbiome metabolites and an oxidized microenvironment are shown to modulate mitochondrial function in ASD tissues. Investigations of treatments for mitochondrial dysfunction in ASD are promising but preliminary. The etiology of mitochondrial dysfunction and how to define it in ASD is currently unclear. However, preliminary evidence suggests that the mitochondria may be a fruitful target for treatment and prevention of ASD. Further research is needed to better understand the role of mitochondrial dysfunction in the pathophysiology of ASD.
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Affiliation(s)
- Shannon Rose
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Dmitriy M Niyazov
- Section of Medical Genetics, Ochsner Health System, New Orleans, LA, USA
| | | | - Michael Goldenthal
- Department of Pediatrics, Neurology Section, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA, USA
| | - Stephen G Kahler
- Department of Pediatrics, University of Arkansas for Medical Sciences and Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Richard E Frye
- Division of Neurodevelopmental Disorders, Department of Neurology, Barrow Neurological Institute, Phoenix Children's Hospital, 1919 E Thomas St, Phoenix, AZ, USA.
- Department of Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, AZ, USA.
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Lebeau J, Rainbolt TK, Wiseman RL. Coordinating Mitochondrial Biology Through the Stress-Responsive Regulation of Mitochondrial Proteases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 340:79-128. [PMID: 30072094 PMCID: PMC6402875 DOI: 10.1016/bs.ircmb.2018.05.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteases are localized throughout mitochondria and function as critical regulators of all aspects of mitochondrial biology. As such, the activities of these proteases are sensitively regulated through transcriptional and post-translational mechanisms to adapt mitochondrial function to specific cellular demands. Here, we discuss the stress-responsive mechanisms responsible for regulating mitochondrial protease activity and the implications of this regulation on mitochondrial function. Furthermore, we describe how imbalances in the activity or regulation of mitochondrial proteases induced by genetic, environmental, or aging-related factors influence mitochondria in the context of disease. Understanding the molecular mechanisms by which cells regulate mitochondrial function through alterations in protease activity provide insights into the contributions of these proteases in pathologic mitochondrial dysfunction and reveals new therapeutic opportunities to ameliorate this dysfunction in the context of diverse classes of human disease.
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Affiliation(s)
- Justine Lebeau
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - T Kelly Rainbolt
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - R Luke Wiseman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
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11
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Baldan F, Gnan C, Franzoni A, Ferino L, Allegri L, Passon N, Damante G. Genomic Deletion Involving the IMMP2L Gene in Two Cases of Autism Spectrum Disorder. Cytogenet Genome Res 2018; 154:196-200. [PMID: 29788020 DOI: 10.1159/000489001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/08/2018] [Indexed: 11/19/2022] Open
Abstract
Mutations/deletions of the IMMP2L gene have been associated with different cognitive/behavioral disturbances, including autism spectrum disorders (ASD). The penetrance of these defects is not complete since they often are inherited from a healthy parent. Using array-CGH in a cohort of 37 ASD patients, we found 2 subjects harboring a deletion inside the IMMP2L gene. In both cases, the IMMP2L gene deletion was inherited: from a healthy mother in one case and from a dyslectic father in the other. In the latter family, the IMMP2L deletion was also detected in the patient's brother, who showed delayed language development. In a cohort of 100 normal controls, no deletions including the IMMP2L gene were observed. However, a recent meta-analysis found no association between IMMP2L deletions and ASD. Our data would indicate that deletions involving the IMMP2L gene may contribute to the development of a subgroup of cognitive/behavioral disorders.
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12
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Gonçalves VF, Cappi C, Hagen CM, Sequeira A, Vawter MP, Derkach A, Zai CC, Hedley PL, Bybjerg-Grauholm J, Pouget JG, Cuperfain AB, Sullivan PF, Christiansen M, Kennedy JL, Sun L. A Comprehensive Analysis of Nuclear-Encoded Mitochondrial Genes in Schizophrenia. Biol Psychiatry 2018; 83:780-789. [PMID: 29628042 PMCID: PMC7168759 DOI: 10.1016/j.biopsych.2018.02.1175] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 02/26/2018] [Accepted: 02/27/2018] [Indexed: 12/14/2022]
Abstract
BACKGROUND The genetic risk factors of schizophrenia (SCZ), a severe psychiatric disorder, are not yet fully understood. Multiple lines of evidence suggest that mitochondrial dysfunction may play a role in SCZ, but comprehensive association studies are lacking. We hypothesized that variants in nuclear-encoded mitochondrial genes influence susceptibility to SCZ. METHODS We conducted gene-based and gene-set analyses using summary association results from the Psychiatric Genomics Consortium Schizophrenia Phase 2 (PGC-SCZ2) genome-wide association study comprising 35,476 cases and 46,839 control subjects. We applied the MAGMA method to three sets of nuclear-encoded mitochondrial genes: oxidative phosphorylation genes, other nuclear-encoded mitochondrial genes, and genes involved in nucleus-mitochondria crosstalk. Furthermore, we conducted a replication study using the iPSYCH SCZ sample of 2290 cases and 21,621 control subjects. RESULTS In the PGC-SCZ2 sample, 1186 mitochondrial genes were analyzed, among which 159 had p values < .05 and 19 remained significant after multiple testing correction. A meta-analysis of 818 genes combining the PGC-SCZ2 and iPSYCH samples resulted in 104 nominally significant and nine significant genes, suggesting a polygenic model for the nuclear-encoded mitochondrial genes. Gene-set analysis, however, did not show significant results. In an in silico protein-protein interaction network analysis, 14 mitochondrial genes interacted directly with 158 SCZ risk genes identified in PGC-SCZ2 (permutation p = .02), and aldosterone signaling in epithelial cells and mitochondrial dysfunction pathways appeared to be overrepresented in this network of mitochondrial and SCZ risk genes. CONCLUSIONS This study provides evidence that specific aspects of mitochondrial function may play a role in SCZ, but we did not observe its broad involvement even using a large sample.
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Affiliation(s)
- Vanessa F Gonçalves
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada; Neuroscience Section, Centre for Addiction and Mental Health, Toronto, Ontario, Canada.
| | - Carolina Cappi
- Department of Psychiatry, University of São Paulo, School of Medicine, Brazil
| | - Christian M Hagen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | - Adolfo Sequeira
- Department of Psychiatry and Human Behavior, University of California, Irvine, USA
| | - Marquis P Vawter
- Department of Psychiatry and Human Behavior, University of California, Irvine, USA
| | - Andriy Derkach
- Department of Statistical Sciences, Faculty of Arts and Science, University of Toronto, Toronto, Canada
| | - Clement C Zai
- Department of Psychiatry, University of Toronto, Toronto, Canada,Neuroscience Section, Centre for Addiction and Mental Health, Toronto, Canada
| | - Paula L Hedley
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark
| | | | - Jennie G Pouget
- Department of Psychiatry, University of Toronto, Toronto, Canada,Neuroscience Section, Centre for Addiction and Mental Health, Toronto, Canada
| | - Ari B. Cuperfain
- Department of Psychiatry, University of Toronto, Toronto, Canada,Neuroscience Section, Centre for Addiction and Mental Health, Toronto, Canada
| | - Patrick F Sullivan
- Department of Genetics, University of North Carolina, Chapel Hill, North Carolina, USA;,Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Michael Christiansen
- Department for Congenital Disorders, Statens Serum Institut, Copenhagen, Denmark,Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - James L Kennedy
- Department of Psychiatry, University of Toronto, Toronto, Canada,Neuroscience Section, Centre for Addiction and Mental Health, Toronto, Canada,Corresponding author: Vanessa F Gonçalves ()
| | - Lei Sun
- Department of Statistical Sciences, Faculty of Arts and Science, University of Toronto, Toronto, Canada,Biostatistics Division, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada,Corresponding author: Vanessa F Gonçalves ()
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13
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Zhang Y, Liu Y, Zarrei M, Tong W, Dong R, Wang Y, Zhang H, Yang X, MacDonald JR, Uddin M, Scherer SW, Gai Z. Association of IMMP2L deletions with autism spectrum disorder: A trio family study and meta-analysis. Am J Med Genet B Neuropsychiatr Genet 2018; 177:93-100. [PMID: 29152845 DOI: 10.1002/ajmg.b.32608] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 08/28/2017] [Accepted: 10/02/2017] [Indexed: 11/10/2022]
Abstract
IMMP2L, the gene encoding the inner mitochondrial membrane peptidase subunit 2-like protein, has been reported as a candidate gene for Tourette syndrome, autism spectrum disorder (ASD) and additional neurodevelopmental disorders. Here we genotyped 100 trio families with an index proband with autism spectrum disorder in Han Chinese population and found three cases with rare exonic IMMP2L deletions. We have conducted a comprehensive meta-analysis to quantify the association of IMMP2L deletions with ASD using 5,568 cases and 10,279 controls. While the IMMP2L deletions carried non-recurrent breakpoints, in contrast to previous reports, our meta-analysis found no evidence of association (P > 0.05) between IMMP2L deletions and ASD. We also observed common exonic deletions impacting IMMP2L in a separate control (5,971 samples) cohort where subjects were screened for psychiatric conditions. This is the first systematic review and meta-analysis regarding the effect of IMMP2L deletions on ASD, but further investigations in different populations, especially Chinese population may be still needed to confirm our results.
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Affiliation(s)
- Yanqing Zhang
- Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Yi Liu
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Mehdi Zarrei
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada
| | - Winnie Tong
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada
| | - Rui Dong
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Ying Wang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Haiyan Zhang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Xiaomeng Yang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Jeffrey R MacDonald
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada
| | - Mohammed Uddin
- Mohammed Bin Rashid University of Medicine and Health Sciences, College of Medicine, Dubai, UAE
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada.,McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Zhongtao Gai
- Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China.,Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
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14
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Fernandez TV, State MW, Pittenger C. Tourette disorder and other tic disorders. HANDBOOK OF CLINICAL NEUROLOGY 2018; 147:343-354. [PMID: 29325623 DOI: 10.1016/b978-0-444-63233-3.00023-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tourette disorder is a developmental neuropsychiatric condition characterized by vocal and motor tics that can range in severity from mild to disabling. It represents one end of a spectrum of tic disorders and is estimated to affect 0.5-0.7% of the population. Accumulated evidence supports a substantial genetic contribution to disease risk, but the identification of genetic variants that confer risk has been challenging. Positive findings in candidate gene association studies have not replicated, and genomewide association studies have not generated signals of genomewide significance, in large part because of inadequate sample sizes. Rare mutations in several genes have been identified, but their causality is difficult to establish. As in other complex neuropsychiatric disorders, it is likely that Tourette disorder risk involves a combination of common, low-effect and rare, larger-effect variants in multiple genes acting together with environmental factors. With the ongoing collection of larger patient cohorts and the emergence of affordable high-throughput genomewide sequencing, progress is expected to accelerate in coming years.
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Affiliation(s)
- Thomas V Fernandez
- Child Study Center, Yale School of Medicine, New Haven, CT, United States
| | - Matthew W State
- Department of Psychiatry, University of California San Francisco, San Francisco, CA, United States
| | - Christopher Pittenger
- Child Study Center, Yale School of Medicine, New Haven, CT, United States; Department of Psychiatry, Yale University, New Haven, CT, United States.
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15
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Jiang Y, Liu C, Lei B, Xu X, Lu B. Mitochondria-targeted antioxidant SkQ1 improves spermatogenesis in Immp2l
mutant mice. Andrologia 2017; 50. [PMID: 28703400 DOI: 10.1111/and.12848] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2017] [Indexed: 11/30/2022] Open
Affiliation(s)
- Yaodong Jiang
- Department of Urology; Nanfang Hospital; Southern Medical University; Guangdong China
- Wake Forest Institute for Regenerative Medicine; Wake Forest University Health Sciences; Winston-Salem NC USA
| | - Chunlian Liu
- Wake Forest Institute for Regenerative Medicine; Wake Forest University Health Sciences; Winston-Salem NC USA
- Center for Reproductive Medicine; General Hospital; Ningxia Medical University; Ningxia China
- Key Laboratory of Fertility Preservation and Maintenance; Ministry of Education; Ningxia Medical University; Ningxia China
| | - Bin Lei
- Department of Urology; The First Affiliated Hospital of Jinan University; Guangzhou China
| | - Xian Xu
- Center for Reproductive Medicine; General Hospital; Ningxia Medical University; Ningxia China
- Key Laboratory of Fertility Preservation and Maintenance; Ministry of Education; Ningxia Medical University; Ningxia China
| | - Baisong Lu
- Wake Forest Institute for Regenerative Medicine; Wake Forest University Health Sciences; Winston-Salem NC USA
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16
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Reilly J, Gallagher L, Chen JL, Leader G, Shen S. Bio-collections in autism research. Mol Autism 2017; 8:34. [PMID: 28702161 PMCID: PMC5504648 DOI: 10.1186/s13229-017-0154-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/23/2017] [Indexed: 01/06/2023] Open
Abstract
Autism spectrum disorder (ASD) is a group of complex neurodevelopmental disorders with diverse clinical manifestations and symptoms. In the last 10 years, there have been significant advances in understanding the genetic basis for ASD, critically supported through the establishment of ASD bio-collections and application in research. Here, we summarise a selection of major ASD bio-collections and their associated findings. Collectively, these include mapping ASD candidate genes, assessing the nature and frequency of gene mutations and their association with ASD clinical subgroups, insights into related molecular pathways such as the synapses, chromatin remodelling, transcription and ASD-related brain regions. We also briefly review emerging studies on the use of induced pluripotent stem cells (iPSCs) to potentially model ASD in culture. These provide deeper insight into ASD progression during development and could generate human cell models for drug screening. Finally, we provide perspectives concerning the utilities of ASD bio-collections and limitations, and highlight considerations in setting up a new bio-collection for ASD research.
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Affiliation(s)
- Jamie Reilly
- Regenerative Medicine Institute, School of Medicine, BioMedical Sciences Building, National University of Ireland (NUI), Galway, Ireland
| | - Louise Gallagher
- Trinity Translational Medicine Institute and Department of Psychiatry, Trinity Centre for Health Sciences, St. James Hospital Street, Dublin 8, Ireland
| | - June L Chen
- Department of Special Education, Faculty of Education, East China Normal University, Shanghai, 200062 China
| | - Geraldine Leader
- Irish Centre for Autism and Neurodevelopmental Research (ICAN), Department of Psychology, National University of Ireland Galway, University Road, Galway, Ireland
| | - Sanbing Shen
- Regenerative Medicine Institute, School of Medicine, BioMedical Sciences Building, National University of Ireland (NUI), Galway, Ireland
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Abstract
Gilles de la Tourette syndrome (GTS) is a childhood-onset neurodevelopmental disorder that is characterized by several motor and phonic tics. Tics usually develop before 10 years of age, exhibit a waxing and waning course and typically improve with increasing age. A prevalence of approximately 1% is estimated in children and adolescents. The condition can result in considerable social stigma and poor quality of life, especially when tics are severe (for example, with coprolalia (swearing tics) and self-injurious behaviours) or when GTS is accompanied by attention-deficit/hyperactivity disorder, obsessive-compulsive disorder or another neuropsychiatric disorder. The aetiology is complex and multifactorial. GTS is considered to be polygenic, involving multiple common risk variants combined with rare, inherited or de novo mutations. These as well as non-genetic factors (such as perinatal events and immunological factors) are likely to contribute to the heterogeneity of the clinical phenotype, the structural and functional brain anomalies and the neural circuitry involvement. Management usually includes psychoeducation and reassurance, behavioural methods, pharmacotherapy and, rarely, functional neurosurgery. Future research that integrates clinical and neurobiological data, including neuroimaging and genetics, is expected to reveal the pathogenesis of GTS at the neural circuit level, which may lead to targeted interventions.
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18
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CTNNA3 discordant regulation of nested LRRTM3, implications for autism spectrum disorder and Tourette syndrome. Meta Gene 2017. [DOI: 10.1016/j.mgene.2016.11.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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19
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Levytskyy RM, Germany EM, Khalimonchuk O. Mitochondrial Quality Control Proteases in Neuronal Welfare. J Neuroimmune Pharmacol 2016; 11:629-644. [PMID: 27137937 PMCID: PMC5093085 DOI: 10.1007/s11481-016-9683-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/27/2016] [Indexed: 01/01/2023]
Abstract
The functional integrity of mitochondria is a critical determinant of neuronal health and compromised mitochondrial function is a commonly recognized factor that underlies a plethora of neurological and neurodegenerative diseases. Metabolic demands of neural cells require high bioenergetic outputs that are often associated with enhanced production of reactive oxygen species. Unopposed accumulation of these respiratory byproducts over time leads to oxidative damage and imbalanced protein homeostasis within mitochondrial subcompartments, which in turn may result in cellular demise. The post-mitotic nature of neurons and their vulnerability to these stress factors necessitate strict protein homeostatic control to prevent such scenarios. A series of evolutionarily conserved proteases is one of the central elements of mitochondrial quality control. These versatile proteolytic enzymes conduct a multitude of activities to preserve normal mitochondrial function during organelle biogenesis, metabolic remodeling and stress. In this review we discuss neuroprotective aspects of mitochondrial quality control proteases and neuropathological manifestations arising from defective proteolysis within the mitochondrion.
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Affiliation(s)
- Roman M Levytskyy
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Edward M Germany
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
- Nebraska Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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Abstract
Mitochondrial diseases are a clinically heterogeneous group of disorders that ultimately result from dysfunction of the mitochondrial respiratory chain. There is some evidence to suggest that mitochondrial dysfunction plays a role in neuropsychiatric illness; however, the data are inconclusive. This article summarizes the available literature published in the area of neuropsychiatric manifestations in both children and adults with primary mitochondrial disease, with a focus on autism spectrum disorder in children and mood disorders and schizophrenia in adults.
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Affiliation(s)
- Samantha E Marin
- Department of Neurosciences, University of California, San Diego (UCSD), 9500 Gilman Drive #0935, La Jolla, CA 92093-0935, USA
| | - Russell P Saneto
- Department of Neurology, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way Northeast, Seattle, WA 98105, USA; Department of Pediatrics, Seattle Children's Hospital, University of Washington, 4800 Sand Point Way Northeast, Seattle, WA 98105, USA.
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21
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Georgitsi M, Willsey AJ, Mathews CA, State M, Scharf JM, Paschou P. The Genetic Etiology of Tourette Syndrome: Large-Scale Collaborative Efforts on the Precipice of Discovery. Front Neurosci 2016; 10:351. [PMID: 27536211 PMCID: PMC4971013 DOI: 10.3389/fnins.2016.00351] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/12/2016] [Indexed: 12/17/2022] Open
Abstract
Gilles de la Tourette Syndrome (TS) is a childhood-onset neurodevelopmental disorder that is characterized by multiple motor and phonic tics. It has a complex etiology with multiple genes likely interacting with environmental factors to lead to the onset of symptoms. The genetic basis of the disorder remains elusive. However, multiple resources and large-scale projects are coming together, launching a new era in the field and bringing us on the verge of discovery. The large-scale efforts outlined in this report are complementary and represent a range of different approaches to the study of disorders with complex inheritance. The Tourette Syndrome Association International Consortium for Genetics (TSAICG) has focused on large families, parent-proband trios and cases for large case-control designs such as genomewide association studies (GWAS), copy number variation (CNV) scans, and exome/genome sequencing. TIC Genetics targets rare, large effect size mutations in simplex trios, and multigenerational families. The European Multicentre Tics in Children Study (EMTICS) seeks to elucidate gene-environment interactions including the involvement of infection and immune mechanisms in TS etiology. Finally, TS-EUROTRAIN, a Marie Curie Initial Training Network, aims to act as a platform to unify large-scale projects in the field and to educate the next generation of experts. Importantly, these complementary large-scale efforts are joining forces to uncover the full range of genetic variation and environmental risk factors for TS, holding great promise for identifying definitive TS susceptibility genes and shedding light into the complex pathophysiology of this disorder.
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Affiliation(s)
- Marianthi Georgitsi
- Department of Molecular Biology and Genetics, Democritus University of ThraceAlexandroupoli, Greece; Department of Medicine, Aristotle University of ThessalonikiThessaloniki, Greece
| | - A Jeremy Willsey
- Department of Psychiatry, University of California, San Francisco San Francisco, CA, USA
| | - Carol A Mathews
- Department of Psychiatry, University of Florida School of Medicine Gainesville, FL, USA
| | - Matthew State
- Department of Psychiatry, University of California, San Francisco San Francisco, CA, USA
| | - Jeremiah M Scharf
- Departments of Neurology and Psychiatry, Massachusetts General Hospital, Harvard Medical School Boston, MA, USA
| | - Peristera Paschou
- Department of Molecular Biology and Genetics, Democritus University of Thrace Alexandroupoli, Greece
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Karagiannidis I, Tsetsos F, Padmanabhuni SS, Alexander J, Georgitsi M, Paschou P. The Genetics of Gilles de la Tourette Syndrome: a Common Aetiological Basis with Comorbid Disorders? Curr Behav Neurosci Rep 2016. [DOI: 10.1007/s40473-016-0088-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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24
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A personal 35 year perspective on Gilles de la Tourette syndrome: prevalence, phenomenology, comorbidities, and coexistent psychopathologies. Lancet Psychiatry 2015; 2:68-87. [PMID: 26359614 DOI: 10.1016/s2215-0366(14)00132-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 09/15/2014] [Indexed: 02/07/2023]
Abstract
This Series is a personal narrative of my experience with patients with Gilles de la Tourette syndrome and covers its definition and history since the first description in 1825. Controversy entered the prevalence debate early. Although originally considered very rare, in the 1980s, Tourette's syndrome was reported to be common. However, Tourette's syndrome has been shown to occur at a prevalence of about 0·85% to 1%. Tourette's syndrome is more common in the male population, more prominent during childhood, and usually improves, but does not disappear with age. Tourette's syndrome is considered less common in people of sub-Saharan black African, African-American, and American Hispanic ethnic origin. The phenomenology is similar worldwide, indicating a biological basis. The hallmark characteristics are multiple motor and one or more vocal/phonic tics. Other associated features include premonitory urges, a waxing and waning course, and to a much lesser degree, coprolalia. Comorbid disorders are common and are suggested to include obsessive-compulsive disorder and behaviours, attention deficit hyperactivity disorder, and autistic spectrum disorder. Coexistent psychopathologies are suggested to include depression and conduct and personality disorders. Importantly, I argue that Tourette's syndrome is not a unitary condition. Finally, I offer suggestions for future research.
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Abstract
The recent descriptions of widespread random monoallelic expression (RMAE) of genes distributed throughout the autosomal genome indicate that there are more genes subject to RMAE on autosomes than the number of genes on the X chromosome where X-inactivation dictates RMAE of X-linked genes. Several of the autosomal genes that undergo RMAE have independently been implicated in human Mendelian disorders. Thus, parsing the relationship between allele-specific expression of these genes and disease is of interest. Mutations in the human forkhead box P2 gene, FOXP2, cause developmental verbal dyspraxia with profound speech and language deficits. Here, we show that the human FOXP2 gene undergoes RMAE. Studying an individual with developmental verbal dyspraxia, we identify a deletion 3 Mb away from the FOXP2 gene, which impacts FOXP2 gene expression in cis. Together these data suggest the intriguing possibility that RMAE impacts the haploinsufficiency phenotypes observed for FOXP2 mutations.
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26
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Liang S, Wang XL, Zou MY, Wang H, Zhou X, Sun CH, Xia W, Wu LJ, Fujisawa TX, Tomoda A. Family-based association study of ZNF533, DOCK4 and IMMP2L gene polymorphisms linked to autism in a northeastern Chinese Han population. J Zhejiang Univ Sci B 2014; 15:264-71. [PMID: 24599690 DOI: 10.1631/jzus.b1300133] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE A study in a Caucasian population has identified two single-nucleotide polymorphisms (SNPs) in ZNF533, one in DOCK4, and two in IMMP2L, which were all significantly associated with autism. They are located in AUTS1 and AUTS5, which have been identified as autism susceptibility loci in several genome-wide screens. The present study aimed to investigate whether ZNF533, DOCK4, and IMMP2L genes are also associated with autism in a northeastern Chinese Han population. METHODS We performed a similar association study using families with three individuals (one autistic child and two unaffected parents). A family-based transmission disequilibrium test (TDT) was used to analyze the results. RESULTS There were significant associations between autism and the two SNPs of ZNF533 gene (rs11885327: χ(2)=4.5200, P=0.0335; rs1964081: χ(2)=4.2610, P=0.0390) and the SNP of DOCK4 gene (rs2217262: χ(2)=5.3430, P=0.0208). CONCLUSIONS Our data suggest that ZNF533 and DOCK4 genes are linked to a predisposition to autism in the northeastern Chinese Han population.
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Affiliation(s)
- Shuang Liang
- Department of Children's and Adolescent Health, Public Health College of Harbin Medical University, Harbin 150081, China; Research Center for Child Mental Development, University of Fukui, 23-3 Matsuoka-Shimoaizuki, Eiheiji-cho, Fukui 910-1193, Japan
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Bertelsen B, Melchior L, Jensen LR, Groth C, Glenthøj B, Rizzo R, Debes NM, Skov L, Brøndum-Nielsen K, Paschou P, Silahtaroglu A, Tümer Z. Intragenic deletions affecting two alternative transcripts of the IMMP2L gene in patients with Tourette syndrome. Eur J Hum Genet 2014; 22:1283-9. [PMID: 24549057 PMCID: PMC4200436 DOI: 10.1038/ejhg.2014.24] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/10/2013] [Accepted: 01/22/2014] [Indexed: 11/09/2022] Open
Abstract
Tourette syndrome is a neurodevelopmental disorder characterized by multiple motor and vocal tics, and the disorder is often accompanied by comorbidities such as attention-deficit hyperactivity-disorder and obsessive compulsive disorder. Tourette syndrome has a complex etiology, but the underlying environmental and genetic factors are largely unknown. IMMP2L (inner mitochondrial membrane peptidase, subunit 2) located on chromosome 7q31 is one of the genes suggested as a susceptibility factor in disease pathogenesis. Through screening of a Danish cohort comprising 188 unrelated Tourette syndrome patients for copy number variations, we identified seven patients with intragenic IMMP2L deletions (3.7%), and this frequency was significantly higher (P=0.0447) compared with a Danish control cohort (0.9%). Four of the seven deletions identified did not include any known exons of IMMP2L, but were within intron 3. These deletions were found to affect a shorter IMMP2L mRNA species with two alternative 5'-exons (one including the ATG start codon). We showed that both transcripts (long and short) were expressed in several brain regions, with a particularly high expression in cerebellum and hippocampus. The current findings give further evidence for the role of IMMP2L as a susceptibility factor in Tourette syndrome and suggest that intronic changes in disease susceptibility genes should be investigated further for presence of alternatively spliced exons.
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Affiliation(s)
- Birgitte Bertelsen
- Applied Human Molecular Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Linea Melchior
- Applied Human Molecular Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
| | - Lars R Jensen
- Institute for Human Genetics, Ernst-Moritz-Arndt-University Greifswald, Griefswald, Germany
| | - Camilla Groth
- The Tourette Clinic, Department of Pediatrics, Herlev University Hospital, Herlev, Denmark
| | - Birte Glenthøj
- Center for Neuropsychiatric Schizophrenia Research and Center for Clinical Intervention and Neuropsychiatric Schizophrenia Research, Copenhagen University Hospital, Psychiatric Center Glostrup, Glostrup, Denmark
| | - Renata Rizzo
- Section of Child Neuropsychiatry, Department of Pediatrics, University of Catania, Catania, Italy
| | - Nanette Mol Debes
- The Tourette Clinic, Department of Pediatrics, Herlev University Hospital, Herlev, Denmark
| | - Liselotte Skov
- The Tourette Clinic, Department of Pediatrics, Herlev University Hospital, Herlev, Denmark
| | - Karen Brøndum-Nielsen
- Applied Human Molecular Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
- Institute for Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Peristera Paschou
- Department of Molecular Biology and Genetics, Democritus University of Thrace, Alexandroupoli, Greece
| | - Asli Silahtaroglu
- Institute for Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Zeynep Tümer
- Applied Human Molecular Genetics, Kennedy Center, Copenhagen University Hospital, Rigshospitalet, Glostrup, Denmark
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Gimelli S, Capra V, Di Rocco M, Leoni M, Mirabelli-Badenier M, Schiaffino MC, Fiorio P, Cuoco C, Gimelli G, Tassano E. Interstitial 7q31.1 copy number variations disrupting IMMP2L gene are associated with a wide spectrum of neurodevelopmental disorders. Mol Cytogenet 2014; 7:54. [PMID: 25478008 PMCID: PMC4255718 DOI: 10.1186/s13039-014-0054-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 07/25/2014] [Indexed: 01/14/2023] Open
Abstract
Background Since the introduction of the array-CGH technique in the diagnostic workup of mental retardation, new recurrent copy number variations and novel microdeletion/microduplication syndromes were identified. These findings suggest that some genomic disorders have high penetrance but a wide range of phenotypic severity. Results We present the clinical and molecular description of four unrelated patients affected by neurodevelopmental disorders and overlapping 7q31.1 microdeletion/microduplication, identified by array-CGH and involving only part of the IMMP2L gene. Conclusion IMMP2L encodes an inner mitochondrial membrane protease-like protein, which is required for processing of cytochromes inside mitochondria. Numerous studies reported that this gene is implicated in behavioural disorders such as autistic spectrum disorders, attention-deficit hyperactivity disorders, and Gilles de la Tourette syndrome. We discuss the functions of the gene suggesting that IMMP2L may act as risk factor for neurological disease.
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Affiliation(s)
- Stefania Gimelli
- Service of Genetic Medicine, University Hospitals of Geneva, Geneva, Switzerland
| | - Valeria Capra
- U.O. Neurochirurgia, Istituto G.Gaslini, Genoa, Italy
| | | | | | - Marisol Mirabelli-Badenier
- DINOMGI Dipartimento-Università di Genova; U.O. Neuropsichiatria infantile, Istituto G. Gaslini, Genoa, Italy
| | | | - Patrizia Fiorio
- Laboratorio di Citogenetica, Istituto G. Gaslini, G.Gaslini 5, Genoa, 16147, Italy
| | - Cristina Cuoco
- Laboratorio di Citogenetica, Istituto G. Gaslini, G.Gaslini 5, Genoa, 16147, Italy
| | - Giorgio Gimelli
- Laboratorio di Citogenetica, Istituto G. Gaslini, G.Gaslini 5, Genoa, 16147, Italy
| | - Elisa Tassano
- Laboratorio di Citogenetica, Istituto G. Gaslini, G.Gaslini 5, Genoa, 16147, Italy
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Bertelsen B, Debes NM, Hjermind LE, Skov L, Brøndum-Nielsen K, Tümer Z. Chromosomal rearrangements in Tourette syndrome: implications for identification of candidate susceptibility genes and review of the literature. Neurogenetics 2013; 14:197-203. [DOI: 10.1007/s10048-013-0372-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Accepted: 08/14/2013] [Indexed: 12/25/2022]
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30
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Paschou P. The genetic basis of Gilles de la Tourette Syndrome. Neurosci Biobehav Rev 2013; 37:1026-39. [DOI: 10.1016/j.neubiorev.2013.01.016] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 01/02/2013] [Accepted: 01/07/2013] [Indexed: 12/18/2022]
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Guo Y, Su L, Zhang J, Lei J, Deng X, Xu H, Yang Z, Kuang S, Tang J, Luo Z, Deng H. Analysis of the BTBD9 and HTR2C variants in Chinese Han patients with Tourette syndrome. Psychiatr Genet 2012; 22:300-3. [DOI: 10.1097/ypg.0b013e32835862b1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Pathogenetic model for Tourette syndrome delineates overlap with related neurodevelopmental disorders including Autism. Transl Psychiatry 2012; 2:e158. [PMID: 22948383 PMCID: PMC3565204 DOI: 10.1038/tp.2012.75] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Tourette syndrome (TS) is a highly heritable neuropsychiatric disorder characterised by motor and vocal tics. Despite decades of research, the aetiology of TS has remained elusive. Recent successes in gene discovery backed by rapidly advancing genomic technologies have given us new insights into the genetic basis of the disorder, but the growing collection of rare and disparate findings have added confusion and complexity to the attempts to translate these findings into neurobiological mechanisms resulting in symptom genesis. In this review, we explore a previously unrecognised genetic link between TS and a competing series of trans-synaptic complexes (neurexins (NRXNs), neuroligins (NLGNs), leucine-rich repeat transmembrane proteins (LRRTMs), leucine rich repeat neuronals (LRRNs) and cerebellin precursor 2 (CBLN2)) that links it with autism spectrum disorder through neurodevelopmental pathways. The emergent neuropathogenetic model integrates all five genes so far found to be uniquely disrupted in TS into a single pathogenetic chain of events described in context with clinical and research implications.
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Analysis of the MRPL3, DNAJC13 and OFCC1 variants in Chinese Han patients with TS-CTD. Neurosci Lett 2012; 517:18-20. [PMID: 22507240 DOI: 10.1016/j.neulet.2012.03.097] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 03/21/2012] [Accepted: 03/31/2012] [Indexed: 11/21/2022]
Abstract
Tourette syndrome/chronic tic phenotype (TS-CTD) is a neurological disorder manifested particularly by motor and vocal tics and associated with a variety of behavioral abnormalities. Recently, the mitochondrial ribosomal protein L3 gene (MRPL3) S75N, the DnaJ (Hsp40) homolog subfamily C member 13 gene (DNAJC13) A2057S, the orofacial cleft 1 candidate 1 gene (OFCC1) R129G and c.-5A>G variants are reported to be associated with Tourette syndrome/chronic tic phenotype (TS-CTD) in patients of European ancestry. To evaluate whether these variants are associated with TS-CTD in Chinese Han patients, we screened 132 Chinese Han patients from Mainland China. None of the 132 samples from patients with TS-CTD showed the MRPL3 S75N, DNAJC13 A2057S, OFCC1 R129G and c.-5A>G variants, and these variants probably are a rare cause of TS-CTD in a Chinese Han ethnic group. Genetic heterogeneity of TS should be considered and tests designed to detect these variants in Chinese Han ethnic group probably will not have a diagnostic utility in clinical practice.
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Abstract
A comprehensive literature search was performed to collate evidence of mitochondrial dysfunction in autism spectrum disorders (ASDs) with two primary objectives. First, features of mitochondrial dysfunction in the general population of children with ASD were identified. Second, characteristics of mitochondrial dysfunction in children with ASD and concomitant mitochondrial disease (MD) were compared with published literature of two general populations: ASD children without MD, and non-ASD children with MD. The prevalence of MD in the general population of ASD was 5.0% (95% confidence interval 3.2, 6.9%), much higher than found in the general population (≈ 0.01%). The prevalence of abnormal biomarker values of mitochondrial dysfunction was high in ASD, much higher than the prevalence of MD. Variances and mean values of many mitochondrial biomarkers (lactate, pyruvate, carnitine and ubiquinone) were significantly different between ASD and controls. Some markers correlated with ASD severity. Neuroimaging, in vitro and post-mortem brain studies were consistent with an elevated prevalence of mitochondrial dysfunction in ASD. Taken together, these findings suggest children with ASD have a spectrum of mitochondrial dysfunction of differing severity. Eighteen publications representing a total of 112 children with ASD and MD (ASD/MD) were identified. The prevalence of developmental regression (52%), seizures (41%), motor delay (51%), gastrointestinal abnormalities (74%), female gender (39%), and elevated lactate (78%) and pyruvate (45%) was significantly higher in ASD/MD compared with the general ASD population. The prevalence of many of these abnormalities was similar to the general population of children with MD, suggesting that ASD/MD represents a distinct subgroup of children with MD. Most ASD/MD cases (79%) were not associated with genetic abnormalities, raising the possibility of secondary mitochondrial dysfunction. Treatment studies for ASD/MD were limited, although improvements were noted in some studies with carnitine, co-enzyme Q10 and B-vitamins. Many studies suffered from limitations, including small sample sizes, referral or publication biases, and variability in protocols for selecting children for MD workup, collecting mitochondrial biomarkers and defining MD. Overall, this evidence supports the notion that mitochondrial dysfunction is associated with ASD. Additional studies are needed to further define the role of mitochondrial dysfunction in ASD.
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Matsuzaki H, Iwata K, Manabe T, Mori N. Triggers for autism: genetic and environmental factors. J Cent Nerv Syst Dis 2012; 4:27-36. [PMID: 23650465 PMCID: PMC3619552 DOI: 10.4137/jcnsd.s9058] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
This report reviews the research on the factors that cause autism. In several studies, these factors have been verified by reproducing them in autistic animal models. Clinical research has demonstrated that genetic and environmental factors play a major role in the development of autism. However, most cases are idiopathic, and no single factor can explain the trends in the pathology and prevalence of autism. At the time of this writing, autism is viewed more as a multi-factorial disorder. However, the existence of an unknown factor that may be common in all autistic cases cannot be ruled out. It is hoped that future biological studies of autism will help construct a new theory that can interpret the pathology of autism in a coherent manner. To achieve this, large-scale epidemiological research is essential.
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Affiliation(s)
- Hideo Matsuzaki
- Research Center for Child Mental Development, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Abstract
Background Wig-1 is a transcription factor regulated by p53 that can interact with hnRNP A2/B1, RNA Helicase A, and dsRNAs, which plays an important role in RNA and protein stabilization. in vitro studies have shown that wig-1 binds p53 mRNA and stabilizes it by protecting it from deadenylation. Furthermore, p53 has been implicated as a causal factor in neurodegenerative diseases based in part on its selective regulatory function on gene expression, including genes which, in turn, also possess regulatory functions on gene expression. In this study we focused on the wig-1 transcription factor as a downstream p53 regulated gene and characterized the effects of wig-1 down regulation on gene expression in mouse liver and brain. Methods and Results Antisense oligonucleotides (ASOs) were identified that specifically target mouse wig-1 mRNA and produce a dose-dependent reduction in wig-1 mRNA levels in cell culture. These wig-1 ASOs produced marked reductions in wig-1 levels in liver following intraperitoneal administration and in brain tissue following ASO administration through a single striatal bolus injection in FVB and BACHD mice. Wig-1 suppression was well tolerated and resulted in the reduction of mutant Htt protein levels in BACHD mouse brain but had no effect on normal Htt protein levels nor p53 mRNA or protein levels. Expression microarray analysis was employed to determine the effects of wig-1 suppression on genome-wide expression in mouse liver and brain. Reduction of wig-1 caused both down regulation and up regulation of several genes, and a number of wig-1 regulated genes were identified that potentially links wig-1 various signaling pathways and diseases. Conclusion Antisense oligonucleotides can effectively reduce wig-1 levels in mouse liver and brain, which results in specific changes in gene expression for pathways relevant to both the nervous system and cancer.
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Genetics and Epigenetics of Autism Spectrum Disorders. RESEARCH AND PERSPECTIVES IN NEUROSCIENCES 2012. [DOI: 10.1007/978-3-642-27913-3_10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Patel C, Cooper-Charles L, McMullan DJ, Walker JM, Davison V, Morton J. Translocation breakpoint at 7q31 associated with tics: further evidence for IMMP2L as a candidate gene for Tourette syndrome. Eur J Hum Genet 2011; 19:634-9. [PMID: 21386874 DOI: 10.1038/ejhg.2010.238] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Gilles de la Tourette syndrome is a complex neuropsychiatric disorder with a strong genetic basis. We identified a male patient with Tourette syndrome-like tics and an apparently balanced de novo translocation [46,XY,t(2;7)(p24.2;q31)]. Further analysis using array comparative genomic hybridisation (CGH) revealed a cryptic deletion at 7q31.1-7q31.2. Breakpoints disrupting this region have been reported in one isolated and one familial case of Tourette syndrome. In our case, IMMP2L, a gene coding for a human homologue of the yeast inner mitochondrial membrane peptidase subunit 2, was disrupted by the breakpoint on 7q31.1, with deletion of exons 1-3 of the gene. The IMMP2L gene has previously been proposed as a candidate gene for Tourette syndrome, and our case provides further evidence of its possible role in the pathogenesis. The deleted region (7q31.1-7q31.2) of 7.2 Mb of genomic DNA also encompasses numerous genes, including FOXP2, associated with verbal dyspraxia, and the CFTR gene.
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Affiliation(s)
- Chirag Patel
- Department of Clinical Genetics, Birmingham Women's Hospital NHS Foundation Trust, Birmingham, UK.
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State MW. The genetics of Tourette disorder. Curr Opin Genet Dev 2011; 21:302-9. [PMID: 21277193 DOI: 10.1016/j.gde.2011.01.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 01/03/2011] [Accepted: 01/04/2011] [Indexed: 12/21/2022]
Abstract
Tourette disorder (TD) is a childhood onset neuropsychiatric syndrome defined by persistent motor and vocal tics. Despite a long-standing consensus for a strong genetic contribution, the pace of discovery compared to other disorders of similar prevalence has been slow, due in part to a paucity of studies and both clinical heterogeneity and a complex genetic architecture. However, the potential for rapid progress is high. Recent rare variant findings have pointed to the importance of copy number variation, the overlap of risks among distinct diagnostic entities, the contribution of novel molecular mechanisms, and the value of family based studies. Finally, analysis of a cohort of sufficient size to identify common polymorphisms of plausible effect is underway, promising key information regarding the contribution of common alleles to TD.
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Affiliation(s)
- Matthew W State
- Department of Child Psychiatry, Yale University School of Medicine, New Haven, CT 06520, United States.
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Key role for gene dosage and synaptic homeostasis in autism spectrum disorders. Trends Genet 2010; 26:363-72. [PMID: 20609491 DOI: 10.1016/j.tig.2010.05.007] [Citation(s) in RCA: 228] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2009] [Revised: 05/26/2010] [Accepted: 05/26/2010] [Indexed: 12/19/2022]
Abstract
Autism spectrum disorders (ASD) are characterized by impairments in reciprocal social communication, and repetitive, stereotyped verbal and non-verbal behaviors. Genetic studies have provided a relatively large number of genes that constitute a comprehensive framework to better understand this complex and heterogeneous syndrome. Based on the most robust findings, three observations can be made. First, genetic contributions to ASD are highly heterogeneous and most probably involve a combination of alleles with low and high penetrance. Second, the majority of the mutations apparently affect a single allele, suggesting a key role for gene dosage in susceptibility to ASD. Finally, the broad expression and function of the causative genes suggest that alteration of synaptic homeostasis could be a common biological process associated with ASD. Understanding the mechanisms that regulate synaptic homeostasis should shed new light on the causes of ASD and could provide a means to modulate the severity of the symptoms.
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O’Rourke JA, Scharf JM, Yu D, Pauls DL. The genetics of Tourette syndrome: a review. J Psychosom Res 2009; 67:533-45. [PMID: 19913658 PMCID: PMC2778609 DOI: 10.1016/j.jpsychores.2009.06.006] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 06/23/2009] [Accepted: 06/26/2009] [Indexed: 02/07/2023]
Abstract
OBJECTIVES This article summarizes and evaluates recent advances in the genetics of Gilles de la Tourette syndrome (GTS). METHODS This is a review of recent literature focusing on (1) the genetic etiology of GTS; (2) common genetic components of GTS, attention deficit hyperactivity disorder (ADHD), and obsessive compulsive disorder (OCD); (3) recent linkage studies of GTS; (4) chromosomal translocations in GTS; and (5) candidate gene studies. RESULTS Family, twin, and segregation studies provide strong evidence for the genetic nature of GTS. GTS is a heterogeneous disorder with complex inheritance patterns and phenotypic manifestations. Family studies of GTS and OCD indicate that an early-onset form of OCD is likely to share common genetic factors with GTS. While there apparently is an etiological relationship between GTS and ADHD, it appears that the common form of ADHD does not share genetic factors with GTS. The largest genome wide linkage study to date observed evidence for linkage on chromosome 2p23.2 (P=3.8x10(-5)). No causative candidate genes have been identified, and recent studies suggest that the newly identified candidate gene SLITRK1 is not a significant risk gene for the majority of individuals with GTS. CONCLUSION The genetics of GTS are complex and not well understood. The Genome Wide Association Study (GWAS) design can hopefully overcome the limitations of linkage and candidate gene studies. However, large-scale collaborations are needed to provide enough power to utilize the GWAS design for discovery of causative mutations. Knowledge of susceptibility mutations and biological pathways involved should eventually lead to new treatment paradigms for GTS.
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Lu B, Poirier C, Gaspar T, Gratzke C, Harrison W, Busija D, Matzuk MM, Andersson KE, Overbeek PA, Bishop CE. A mutation in the inner mitochondrial membrane peptidase 2-like gene (Immp2l) affects mitochondrial function and impairs fertility in mice. Biol Reprod 2007; 78:601-10. [PMID: 18094351 DOI: 10.1095/biolreprod.107.065987] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The mitochondrion is involved in energy generation, apoptosis regulation, and calcium homeostasis. Mutations in genes involved in mitochondrial processes often result in a severe phenotype or embryonic lethality, making the study of mitochondrial involvement in aging, neurodegeneration, or reproduction challenging. Using a transgenic insertional mutagenesis strategy, we generated a mouse mutant, Immp2lTg(Tyr)979Ove, with a mutation in the inner mitochondrial membrane peptidase 2-like (Immp2l) gene. The mutation affected the signal peptide sequence processing of mitochondrial proteins cytochrome c1 and glycerol phosphate dehydrogenase 2. The inefficient processing of mitochondrial membrane proteins perturbed mitochondrial function so that mitochondria from mutant mice manifested hyperpolarization, higher than normal superoxide ion generation, and higher levels of ATP. Homozygous Immp2lTg(Tyr)979Ove females were infertile due to defects in folliculogenesis and ovulation, whereas mutant males were severely subfertile due to erectile dysfunction. The data suggest that the high superoxide ion levels lead to a decrease in the bioavailability of nitric oxide and an increase in reactive oxygen species stress, which underlies these reproductive defects. The results provide a novel link between mitochondrial dysfunction and infertility and suggest that superoxide ion targeting agents may prove useful for treating infertility in a subpopulation of infertile patients.
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Affiliation(s)
- Baisong Lu
- Institute for Regenerative Medicine, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina 27157, USA
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