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Yang M, Xu L, Xu C, Cui Y, Jiang S, Dong J, Liao L. The Mutations and Clinical Variability in Maternally Inherited Diabetes and Deafness: An Analysis of 161 Patients. Front Endocrinol (Lausanne) 2021; 12:728043. [PMID: 34899594 PMCID: PMC8654930 DOI: 10.3389/fendo.2021.728043] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 11/01/2021] [Indexed: 12/21/2022] Open
Abstract
Aims To investigate the clinical features and mitochondrial mutations for maternally inherited diabetes and deafness. Methods PubMed, Embase, Medline, Web of Science, the China National Knowledge Infrastructure, and Wanfang were searched with the following search terms: "Maternally inherited diabetes and deafness" OR "MIDD" OR "Mitochondrial diabetes". The mutations and clinical features were analyzed. Correlation between the heteroplasmy levels of the m.3243A>G mutation in the peripheral blood and age at the onset of diabetes was conducted by Spearman test. The significance level was set as p < 0.05. Statistical analysis was performed using the Statistical Package for the Social Sciences version 26 for Windows. Results Totally 161 patients with 21 different mitochondrial mutations were enrolled. The most common mutation was the m.3243A>G mutation in 136 cases. Of 142 patients, 120 (84.51%) had family histories of diabetes or hearing loss. Hearing loss presented in 85.71% of the patients with mitochondrial mutations. Central nervous system diseases were found in 29.19%, myopathy in 22.98%, oculopathy in 23.60%, cardiac disease in 23.60%, and nephropathy in 13.66% of the patients. Forty-two of 101 (41.58%) patients were underweight. A significant negative correlation was found between the heteroplasmy levels of the m.3243A>G mutation in the peripheral blood and age at the onset of diabetes. Conclusions The young onset of diabetes with low or normal BMI, maternal inheritance, and presence of impairments of multiple systems should prompt a genetic testing in order to differentiate MIDD from other types of diabetes earlier.
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Affiliation(s)
- Mengge Yang
- Cheeloo College of Medicine, Shandong University, Department of Endocrinology and Metabology, Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Ji-nan, China
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
| | - Lusi Xu
- Cheeloo College of Medicine, Shandong University, Department of Endocrinology and Metabology, Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Ji-nan, China
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
| | - Chunmei Xu
- Cheeloo College of Medicine, Shandong University, Department of Endocrinology and Metabology, Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Ji-nan, China
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
| | - Yuying Cui
- College of Traditional Chinese Medicine, Shandong University of Traditional Chinese Medicine, Ji-nan, China
| | - Shan Jiang
- Division of Endocrinology, Department of Internal Medicine, Qilu Hospital of Shandong University, Ji-nan, China
| | - Jianjun Dong
- Division of Endocrinology, Department of Internal Medicine, Qilu Hospital of Shandong University, Ji-nan, China
| | - Lin Liao
- Cheeloo College of Medicine, Shandong University, Department of Endocrinology and Metabology, Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Ji-nan, China
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Ji-nan, China
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2
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Shen X, Du A. The non-syndromic clinical spectrums of mtDNA 3243A>G mutation. NEUROSCIENCES (RIYADH, SAUDI ARABIA) 2021; 26:128-133. [PMID: 33814365 PMCID: PMC8024137 DOI: 10.17712/nsj.2021.2.20200145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 01/01/2021] [Indexed: 12/21/2022]
Abstract
The m.3243A >G mutation in the tRNA Leu (UUR) gene (MT-TL1) of the mitochondrial DNA is the most widely seen pathogenic mtDNA mutation which has major phenotypic variations. The clinical phenotype involves various organs such as the brain and nerves, skeletal muscles, heart, endocrine system, gastrointestinal tract, and skin. Some phenotypes conform to well established syndromes, while most of the symptoms appear individually or concomitant to other syndromes, making identification difficult. Furthermore, some progress has been made on cardiac manifestations as well as complications during pregnancy and perinatal period. This article provides a systematic review of the non-syndromic phenotypes and latest developments in m.3243A>G mutation.
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Affiliation(s)
- Xiya Shen
- From the Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Ailian Du
- From the Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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3
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Jiang Z, Teng L, Zhang S, Ding Y. Mitochondrial ND1 T4216C and ND2 C5178A mutations are associated with maternally transmitted diabetes mellitus. Mitochondrial DNA A DNA Mapp Seq Anal 2020; 32:59-65. [PMID: 33284036 DOI: 10.1080/24701394.2020.1856101] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Mutations in mitochondrial DNA (mtDNA) are important causes for type 2 diabetes mellitus (T2DM). To investigate the association between mtDNA mutations/variants and diabetes, we reported here clinical, genetic and biochemical characterization of a Chinese pedigree with maternally transmitted T2DM. Using PCR and direct sequencing analysis of mitochondrial genomes from the matrilineal relatives, we identified two potential pathogenic mutations, m.T4216C (p.Y304H) and m.C5178A (p.L237M) in the ND1 and ND2 genes, respectively, together with a set of genetic polymorphisms belonging to the human mitochondrial haplogroup D4b. Moreover, by isolating and analyzing polymononuclear leukocytes generated from the T2DM patients and controls, we identified lower levels of mitochondrial membrane potential and ATP production in T2DM patients than in the controls, in contrast, a significantly higher level of reactive oxygen species was observed in the T2DM patients carrying both of the m.T4216C and m.C5178A mutations (p < 0.05 for all). In addition, the plasma levels of malondialdehyde and 8-hydroxydeoxyguanosine in the T2DM patients markedly increased, while the level of superoxide dismutase decreased (p < 0.05 for all). Taken together, our data indicated that the ND1 T4216C and ND2 C5178A mutations may lead to oxidative stress and impair the mitochondrial function, and this, in turn, might have been involved in the pathogenesis and progression of T2DM in this pedigree. Thus, our study provides novel insight into the pathophysiology of T2DM that is manifested by mitochondrial dysfunction.
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Affiliation(s)
- Zhaochang Jiang
- Department of Pathology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Lili Teng
- Department of Geriatric Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Shunrong Zhang
- Department of Gerontology, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Ding
- Central Laboratory, Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
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4
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Habibzadeh P, Inaloo S, Silawi M, Dastsooz H, Farazi Fard MA, Sadeghipour F, Faghihi Z, Rezaeian M, Yavarian M, Böhm J, Faghihi MA. A Novel TTC19 Mutation in a Patient With Neurological, Psychological, and Gastrointestinal Impairment. Front Neurol 2019; 10:944. [PMID: 31551910 PMCID: PMC6737916 DOI: 10.3389/fneur.2019.00944] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/15/2019] [Indexed: 12/31/2022] Open
Abstract
Mitochondrial complex III deficiency nuclear type 2 is an autosomal-recessive disorder caused by mutations in TTC19 gene. TTC19 is involved in the preservation of mitochondrial complex III, which is responsible for transfer of electrons from reduced coenzyme Q to cytochrome C and thus, contributes to the formation of electrochemical potential and subsequent ATP generation. Mutations in TTC19 have been found to be associated with a wide range of neurological and psychological manifestations. Herein, we report on a 15-year-old boy born from first-degree cousin parents, who initially presented with psychiatric symptoms. He subsequently developed progressive ataxia, spastic paraparesis with involvement of caudate bodies and lentiform nuclei with cerebellar atrophy. Eventually, the patient developed gastrointestinal involvement. Using whole-exome sequencing (WES), we identified a novel homozygous frameshift mutation in the TTC19 gene in the patient (NM_017775.3, c.581delG: p.Arg194Asnfs*16). Advanced genetic sequencing technologies developed in recent years have not only facilitated identification of novel disease genes, but also allowed revelations about novel phenotypes associated with mutations in the genes already linked with other clinical features. Our findings expanded the clinical features of TTC19 mutation to potentially include gastrointestinal involvement. Further functional studies are needed to elucidate the underlying pathophysiological mechanisms.
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Affiliation(s)
- Parham Habibzadeh
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Soroor Inaloo
- Neonatal Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohammad Silawi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Hassan Dastsooz
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Italian Institute for Genomic Medicine (IIGM), University of Turin, Turin, Italy
| | - Mohammad Ali Farazi Fard
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Forough Sadeghipour
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Zahra Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mohaddeseh Rezaeian
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Majid Yavarian
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm, CNRS, Université de Strasbourg, Illkirch, France
| | - Mohammad Ali Faghihi
- Persian BayanGene Research and Training Center, Shiraz University of Medical Sciences, Shiraz, Iran.,Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences, University of Miami Miller School of Medicine, Miami, FL, United States
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5
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Hoefsmit EP, Rozeman EA, Haanen JBAG, Blank CU. Susceptible loci associated with autoimmune disease as potential biomarkers for checkpoint inhibitor-induced immune-related adverse events. ESMO Open 2019; 4:e000472. [PMID: 31423333 PMCID: PMC6677983 DOI: 10.1136/esmoopen-2018-000472] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 03/01/2019] [Accepted: 03/19/2019] [Indexed: 12/13/2022] Open
Abstract
Unprecedented successes regarding cancer immunotherapy have been achieved, in which therapeutic agents are used to target immune cells rather than cancer cells. The most effective immunotherapy to date is the group of immune checkpoint inhibitors (CPI), targeting, for example, cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) or programmed cell death protein (PD-1). TThe combination of these therapies (anti-PD-1 with anti-CTLA-4) induces high response rates, and seem to be increased further when applied in early-stage disease. However, combined CTLA-4 plus PD-1 blockade causes frequent high-grade immune-related adverse events (irAE). To date, research on biological mechanism of irAEs is scarce and no widely accepted biomarkers predicting onset of severe irAEs have been identified. The similarity of irAEs to autoimmune disorders fuels the hypothesis that irAEs may be linked to susceptible genetic loci related to various autoimmune diseases. In this review, we extensively searched for susceptible loci associated with various autoimmune diseases, and pooled them in groups most likely to be associated with CPI-induced irAEs. These sets could be used in future research on predicting irAEs and guide physicians in a more refined and personal manner.
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Affiliation(s)
- Esmée P Hoefsmit
- Division of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Elisa A Rozeman
- Division of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam, The Netherlands.,Medical Oncology Department, Netherlands Cancer Institute-Antoni van Leeuwenhoek Ziekenhuis, Amsterdam, The Netherlands
| | - John B A G Haanen
- Division of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam, The Netherlands.,Medical Oncology Department, Netherlands Cancer Institute-Antoni van Leeuwenhoek Ziekenhuis, Amsterdam, The Netherlands
| | - Christian U Blank
- Division of Molecular Oncology and Immunology, Netherlands Cancer Institute, Amsterdam, The Netherlands.,Medical Oncology Department, Netherlands Cancer Institute-Antoni van Leeuwenhoek Ziekenhuis, Amsterdam, The Netherlands
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6
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Zhu J, Yang P, Liu X, Yan L, Rampersad S, Li F, Li H, Sheng C, Cheng X, Zhang M, Qu S. The clinical characteristics of patients with mitochondrial tRNA Leu(UUR)m.3243A > G mutation: Compared with type 1 diabetes and early onset type 2 diabetes. J Diabetes Complications 2017; 31:1354-1359. [PMID: 28599824 DOI: 10.1016/j.jdiacomp.2017.04.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 03/09/2017] [Accepted: 04/03/2017] [Indexed: 12/22/2022]
Abstract
OBJECTIVE This study presents nine patients with mitochondrial tRNA Leu (UUR) m.3243A>G mutation and compares the clinical characteristics and diabetes complications with type 1 diabetes (T1DM) or early onset type 2 diabetes (T2DM). METHODS The study covers 9 patients with MIDD, 33 patients with T1DM and 86 patients (age of onset ≤35years) with early onset T2DM, matched for sex, age at onset of diabetes, duration of diabetes. All patients with MIDD were confirmed as carrying the m.3243A>G mitochondrial DNA mutation. Serum HbA1c, beta-cell function, retinal and renal complications of diabetes, bone metabolic markers, lumbar spine and femoral neck BMD bone mineral density were compared to characterize the clinical features of all patients. RESULTS Nine patients were from five unrelated families, and the mean (SD) onset age of those patients was 31.2±7.2year. Two patients required insulin at presentation, and six patients progressed to insulin requirement after a mean of 7.2years. β-Cell function in the MIDD group was intermediate between T1DM and early-onset T2DM. In MIDD, four patients were diagnosed as diabetic retinopathy (4/9) and five patients (5/9) had macroalbuminuria. The number of patients with diabetic retinopathy and macroalbuminuria in the MIDD group was comparable to T1DM or early-onset T2DM. The rate of osteoporosis (BMD T-score<-2.5 SD) in the patient with MIDD was higher than the T1DM or early-onset T2DM group. CONCLUSION Our study indicates that of the nine subjects with MIDD, three patients (1-II-1, 1-II-3, 1-II-4) who came from the same family had a history of acute pancreatitis. Compared with T1DM or early-onset T2DM matched for sex, age, duration of diabetes, MIDD patients had the highest rate of osteoporosis.
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MESH Headings
- Adult
- Age of Onset
- Biomarkers/blood
- Biomarkers/urine
- Bone Density
- China/epidemiology
- Deafness/complications
- Deafness/genetics
- Deafness/metabolism
- Deafness/physiopathology
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/physiopathology
- Diabetes Mellitus, Type 1/urine
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/complications
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/physiopathology
- Diabetes Mellitus, Type 2/urine
- Diabetic Nephropathies/epidemiology
- Diabetic Retinopathy/epidemiology
- Female
- Glycated Hemoglobin/analysis
- Humans
- Male
- Mitochondrial Diseases/complications
- Mitochondrial Diseases/genetics
- Mitochondrial Diseases/metabolism
- Mitochondrial Diseases/physiopathology
- Osteoporosis/complications
- Osteoporosis/epidemiology
- Pancreatitis/complications
- Pancreatitis/epidemiology
- Point Mutation
- Prevalence
- RNA, Transfer, Leu
- Young Adult
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Affiliation(s)
- Jie Zhu
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Peng Yang
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Xiang Liu
- Department of Urology, Putuo District People's Hospital, Shanghai 200060, China
| | - Li Yan
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Sharvan Rampersad
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Feng Li
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Hong Li
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Chunjun Sheng
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Xiaoyun Cheng
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
| | - Manna Zhang
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China.
| | - Shen Qu
- Department of Endocrinology & Metabolism, Shanghai Tenth People's Hospital, Tongji University School of Medicine, 301 Middle Yanchang Road, Shanghai 200072, China
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7
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Patient care standards for primary mitochondrial disease: a consensus statement from the Mitochondrial Medicine Society. Genet Med 2017; 19:S1098-3600(21)04766-3. [PMID: 28749475 DOI: 10.1038/gim.2017.107] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 05/25/2017] [Indexed: 02/07/2023] Open
Abstract
The purpose of this statement is to provide consensus-based recommendations for optimal management and care for patients with primary mitochondrial disease. This statement is intended for physicians who are engaged in the diagnosis and management of these patients. Working group members were appointed by the Mitochondrial Medicine Society. The panel included members with several different areas of expertise. The panel members utilized surveys and the Delphi method to reach consensus. We anticipate that this statement will need to be updated as the field continues to evolve. Consensus-based recommendations are provided for the routine care and management of patients with primary genetic mitochondrial disease.
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8
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Suzuki J, Iwata M, Moriyoshi H, Nishida S, Yasuda T, Ito Y. Familial Pernicious Chronic Intestinal Pseudo-obstruction with a Mitochondrial DNA A3243G Mutation. Intern Med 2017; 56:1089-1093. [PMID: 28458318 PMCID: PMC5478573 DOI: 10.2169/internalmedicine.56.7753] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We report the case of a mother and two children who shared a mitochondrial DNA A3243G mutation. The mother had diabetes mellitus, neurogenic bladder, bradykinesia, dystonia, and slowly progressive cerebellar ataxia. Her two daughters were diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes at adolescence. They all presented with gastrointestinal symptoms at an advanced clinical stage. They were diagnosed with chronic intestinal pseudo-obstruction, and they were resistant to therapy. The mother and her youngest daughter died from aspiration pneumonia because of vomiting. The determination of chronic intestinal pseudo-obstruction is an important prognostic factor in patients with the mitochondrial DNA A3243G variant.
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Affiliation(s)
| | - Mai Iwata
- Department of Neurology, TOYOTA Memorial Hospital, Japan
| | | | - Suguru Nishida
- Department of Neurology, TOYOTA Memorial Hospital, Japan
| | - Takeshi Yasuda
- Department of Neurology, TOYOTA Memorial Hospital, Japan
| | - Yasuhiro Ito
- Department of Neurology, TOYOTA Memorial Hospital, Japan
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9
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Finsterer J, Zarrouk-Mahjoub S. Mitochondrial multiorgan disorder syndrome score generated from definite mitochondrial disorders. Neuropsychiatr Dis Treat 2017; 13:2569-2579. [PMID: 29062232 PMCID: PMC5638572 DOI: 10.2147/ndt.s149067] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES Mitochondrial disorders (MIDs) frequently present as mitochondrial multiorgan disorder syndrome (MIMODS) at onset or evolve into MIMODS during the course. This study aimed to find which organs and/or tissues are most frequently affected by MIMODS, which are the most frequent abnormalities within an affected organ, whether there are typical MIMODS patterns, and to generate an MIMODS score to assess the diagnostic probability for an MID. METHODS This is a retrospective evaluation of clinical, biochemical, and genetic investigations of adult patients with definite MIDs. A total of 36 definite MID patients, 19 men and 17 women, aged 29-82 years were included in this study. The diagnosis was based on genetic testing (n=21), on biochemical investigations (n=17), or on both (n=2). RESULTS The number of organs most frequently affected was 4 ranging from 1 to 9. MIMODS was diagnosed in 97% of patients. The organs most frequently affected were the muscle (97%), central nervous system (CNS; 72%), endocrine glands (69%), heart (58%), intestines (55%), and peripheral nerves (50%). The most frequent CNS abnormalities were leukoencephalopathy, prolonged visually evoked potentials, and atrophy. The most frequent endocrine abnormalities included thyroid dysfunction, short stature, and diabetes. The most frequent cardiac abnormalities included arrhythmias, systolic dysfunction, and hypertrophic cardiomyopathy. The most frequent MIMODS patterns were encephalomyopathy, encephalo-myo-endocrinopathy, and encepalo-myo-endocrino-cardiopathy. The mean ± 2SD MIMODS score was 35.97±27.6 (range =11-71). An MIMODS score >10 was regarded as indicative of an MID. CONCLUSION Adult MIDs manifest as MIMODS in the vast majority of the cases. The organs most frequently affected in MIMODS are muscles, CNS, endocrine glands, and heart. An MIMODS score >10 suggests an MID.
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10
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Abstract
Mitochondrial disorders (MIDs) due to respiratory-chain defects or nonrespiratory chain defects are usually multisystem conditions [mitochondrial multiorgan disorder syndrome (MIMODS)] affecting the central nervous system (CNS), peripheral nervous system, eyes, ears, endocrine organs, heart, kidneys, bone marrow, lungs, arteries, and also the intestinal tract. Frequent gastrointestinal (GI) manifestations of MIDs include poor appetite, gastroesophageal sphincter dysfunction, constipation, dysphagia, vomiting, gastroparesis, GI pseudo-obstruction, diarrhea, or pancreatitis and hepatopathy. Rare GI manifestations of MIDs include dry mouth, paradontosis, tracheoesophageal fistula, stenosis of the duodeno-jejunal junction, atresia or imperforate anus, liver cysts, pancreas lipomatosis, pancreatic cysts, congenital stenosis or obstruction of the GI tract, recurrent bowel perforations with intra-abdominal abscesses, postprandial abdominal pain, diverticulosis, or pneumatosis coli. Diagnosing GI involvement in MIDs is not at variance from diagnosing GI disorders due to other causes. Treatment of mitochondrial GI disease includes noninvasive or invasive measures. Therapy is usually symptomatic. Only for myo-neuro-gastro-intestinal encephalopathy is a causal therapy with autologous stem-cell transplantation available. It is concluded that GI manifestations of MIDs are more widespread than so far anticipated and that they must be recognized as early as possible to initiate appropriate diagnostic work-up and avoid any mitochondrion-toxic treatment.
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Affiliation(s)
| | - Marlies Frank
- First Medical Department, Krankenanstalt Rudolfstiftung, Vienna, Austria
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11
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Ng YS, Feeney C, Schaefer AM, Holmes CE, Hynd P, Alston CL, Grady JP, Roberts M, Maguire M, Bright A, Taylor RW, Yiannakou Y, McFarland R, Turnbull DM, Gorman GS. Pseudo-obstruction, stroke, and mitochondrial dysfunction: A lethal combination. Ann Neurol 2016; 80:686-692. [PMID: 27453452 PMCID: PMC5215534 DOI: 10.1002/ana.24736] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 06/28/2016] [Accepted: 07/14/2016] [Indexed: 12/28/2022]
Abstract
OBJECTIVES The m.3243A>G MTTL1 mutation is the most common cause of mitochondrial disease; yet there is limited awareness of intestinal pseudo-obstruction (IPO) in this disorder. We aimed to determine the prevalence, severity, and clinical outcome of patients with m.3243A>G-related mitochondrial disease manifesting with IPO. METHODS In this large, observational cohort study, we assessed the clinical, molecular, and radiological characteristics of patients with genetically determined m.3243A>G-related mitochondrial disease, who presented with severe symptoms suggestive of bowel obstruction in the absence of an occluding lesion. RESULTS Between January 2009 and June 2015, 226 patients harbouring the m.3243A>G mutation were recruited to the Medical Research Council Centre Mitochondrial Disease Patient Cohort, Newcastle. Thirty patients (13%) presented acutely with IPO. Thirteen of these patients had a preceding history of stroke-like episodes, whereas 1 presented 27 years previously with their first stroke-like episode. Eight patients developed IPO concomitantly during an acute stroke-like episode. Regression analysis suggested stroke was the strongest predictor for development of IPO, in addition to cardiomyopathy, low body mass index and high urinary mutation load. Poor clinical outcome was observed in 6 patients who underwent surgical procedures. INTERPRETATION Our findings suggest, in this common mitochondrial disease, that IPO is an under-recognized, often misdiagnosed clinical entity. Poor clinical outcome associated with stroke and acute surgical intervention highlights the importance of the neurologist having a high index of suspicion, particularly in the acute setting, to instigate timely coordination of appropriate care and management with other specialists. Ann Neurol 2016;80:686-692.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Catherine Feeney
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew M Schaefer
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Carol Ellen Holmes
- Department of Radiology, The Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Newcastle upon Tyne, United Kingdom
| | - Paula Hynd
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Charlotte L Alston
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - John P Grady
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Mark Roberts
- The Greater Manchester Neuroscience Centre, Salford Royal NHS Foundation Trust, Salford, United Kingdom
| | - Mellisa Maguire
- Department of Neurology, The Leeds Teaching Hospitals NHS Trust, West Yorkshire, United Kingdom
| | - Alexandra Bright
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Robert W Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Yan Yiannakou
- Department of Gastroenterology, County Durham and Darlington NHS Foundation Trust, Durham, United Kingdom
| | - Robert McFarland
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Gráinne S Gorman
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
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Brosens E, Burns AJ, Brooks AS, Matera I, Borrego S, Ceccherini I, Tam PK, García-Barceló MM, Thapar N, Benninga MA, Hofstra RMW, Alves MM. Genetics of enteric neuropathies. Dev Biol 2016; 417:198-208. [PMID: 27426273 DOI: 10.1016/j.ydbio.2016.07.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/13/2016] [Accepted: 07/13/2016] [Indexed: 12/23/2022]
Abstract
Abnormal development or disturbed functioning of the enteric nervous system (ENS), the intrinsic innervation of the gastrointestinal tract, is associated with the development of neuropathic gastrointestinal motility disorders. Here, we review the underlying molecular basis of these disorders and hypothesize that many of them have a common defective biological mechanism. Genetic burden and environmental components affecting this common mechanism are ultimately responsible for disease severity and symptom heterogeneity. We believe that they act together as the fulcrum in a seesaw balanced with harmful and protective factors, and are responsible for a continuum of symptoms ranging from neuronal hyperplasia to absence of neurons.
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Affiliation(s)
- Erwin Brosens
- Department of Clinical Genetics, Erasmus University Medical Centre - Sophia Children's Hospital, Rotterdam, The Netherlands.
| | - Alan J Burns
- Department of Clinical Genetics, Erasmus University Medical Centre - Sophia Children's Hospital, Rotterdam, The Netherlands; Stem Cells and Regenerative Medicine, Birth Defects Research Centre, UCL Institute of Child Health, London, UK
| | - Alice S Brooks
- Department of Clinical Genetics, Erasmus University Medical Centre - Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Ivana Matera
- UOC Medical Genetics, Istituto Giannina Gaslini, Genova, Italy
| | - Salud Borrego
- Department of Genetics, Reproduction and Fetal Medicine, Institute of Biomedicine of Seville (IBIS), Seville, Spain; Centre for Biomedical Network Research on Rare Diseases (CIBERER), Seville, Spain
| | | | - Paul K Tam
- Division of Paediatric Surgery, Department of Surgery, Li Ka Shing Faculty of Medicine of the University of Hong Kong, Hong Kong, China
| | - Maria-Mercè García-Barceló
- State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China; Centre for Reproduction, Development, and Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Nikhil Thapar
- Stem Cells and Regenerative Medicine, Birth Defects Research Centre, UCL Institute of Child Health, London, UK
| | - Marc A Benninga
- Pediatric Gastroenterology, Emma Children's Hospital/Academic Medical Center, Amsterdam, The Netherlands
| | - Robert M W Hofstra
- Department of Clinical Genetics, Erasmus University Medical Centre - Sophia Children's Hospital, Rotterdam, The Netherlands; Stem Cells and Regenerative Medicine, Birth Defects Research Centre, UCL Institute of Child Health, London, UK
| | - Maria M Alves
- Department of Clinical Genetics, Erasmus University Medical Centre - Sophia Children's Hospital, Rotterdam, The Netherlands
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13
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Ng YS, Turnbull DM. Mitochondrial disease: genetics and management. J Neurol 2016; 263:179-91. [PMID: 26315846 PMCID: PMC4723631 DOI: 10.1007/s00415-015-7884-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 08/18/2015] [Accepted: 08/18/2015] [Indexed: 12/14/2022]
Abstract
Mitochondrial disease is one of the most common groups of genetic diseases with a minimum prevalence of greater than 1 in 5000 in adults. Whilst multi-system involvement is often evident, neurological manifestation is the principal presentation in most cases. The multiple clinical phenotypes and the involvement of both the mitochondrial and nuclear genome make mitochondrial disease particularly challenging for the clinician. In this review article we cover mitochondrial genetics and common neurological presentations associated with adult mitochondrial disease. In addition, specific and supportive treatments are discussed.
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Affiliation(s)
- Yi Shiau Ng
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
| | - Doug M Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.
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14
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Multiple gene mutations in patients with type 2 autoimmune pancreatitis and its clinical features. Cent Eur J Immunol 2014; 39:77-82. [PMID: 26155104 PMCID: PMC4439988 DOI: 10.5114/ceji.2014.42129] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 01/15/2014] [Indexed: 12/23/2022] Open
Abstract
Background It is now clear that there are two histological types (type 1 and type 2) of autoimmune pancreatitis (AI P). The histological substance of type 1 AI P is known as lymphoplasmacytic sclerosing pancreatitis (LPSP) or traditional AIP, and type 2 AIP is characterized by distinct histology called idiopathic duct centric pancreatitis (IDCP). Serum IgG4 increase is considered as a marker for type 1 AI P. Far less is known about type 2 and it lacks predicting markers, so it easily leads to missed diagnosis and misdiagnosis. The aim of this study The aim of this study was to describe multi-gene mutations in patients with type 2 AI P and its clinical features. Material and methods Three unrelated patients with type 2 AI P, 10 cases with type 1 AIP, 15 cases with other chronic pancreatitis and 120 healthy individuals were studied. The mutations and polymorphisms of 6 genes involved in chronic pancreatitis or pancreatic cancer — PRSS1, SPINK1, CFTR, MEN1, PKHD1, and mitochondrial DNA – were sequenced. Information of clinical data was collected by personal interview using a structured questionnaire. Results Novel mutations were found in the genes encoding for MEN1 (p.546 Ala > The) and PKHD1 (c. 233586 A > G and c. 316713 C > T) from patients with type 2 AIP. What is more, the serum TCR (T cell receptor) level is relatively higher in patients with type 2 AIP than in patients with type 1 AIP and other chronic pancreatitis or normal controls. Weight loss was the major manifestation and no patients had extrapancreatic involvement in type 2 AIP. Conclusions Type 2 AIP may occur with multi-gene mutations. For screening purposes, it is more reasonable to evaluate TCR levels in serum.
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Schaefer AM, Walker M, Turnbull DM, Taylor RW. Endocrine disorders in mitochondrial disease. Mol Cell Endocrinol 2013; 379:2-11. [PMID: 23769710 PMCID: PMC3820028 DOI: 10.1016/j.mce.2013.06.004] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 04/30/2013] [Accepted: 06/06/2013] [Indexed: 02/09/2023]
Abstract
Endocrine dysfunction in mitochondrial disease is commonplace, but predominantly restricted to disease of the endocrine pancreas resulting in diabetes mellitus. Other endocrine manifestations occur, but are relatively rare by comparison. In mitochondrial disease, neuromuscular symptoms often dominate the clinical phenotype, but it is of paramount importance to appreciate the multi-system nature of the disease, of which endocrine dysfunction may be a part. The numerous phenotypes attributable to pathogenic mutations in both the mitochondrial (mtDNA) and nuclear DNA creates a complex and heterogeneous catalogue of disease which can be difficult to navigate for novices and experts alike. In this article we provide an overview of the endocrine disorders associated with mitochondrial disease, the way in which the underlying mitochondrial disorder influences the clinical presentation, and how these factors influence subsequent management.
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Affiliation(s)
- Andrew M. Schaefer
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
- Corresponding authors. Address: Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Tel.: +44 1912223685.
| | - Mark Walker
- Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Douglass M. Turnbull
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
| | - Robert W. Taylor
- Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
- Corresponding authors. Address: Wellcome Trust Centre for Mitochondrial Research, Institute for Ageing and Health, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, UK. Tel.: +44 1912223685.
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Ishiyama A, Komaki H, Saito T, Saito Y, Nakagawa E, Sugai K, Itagaki Y, Matsuzaki K, Nakura M, Nishino I, Goto YI, Sasaki M. Unusual exocrine complication of pancreatitis in mitochondrial disease. Brain Dev 2013. [PMID: 23182449 DOI: 10.1016/j.braindev.2012.10.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
No association between mitochondrial disease and pancreatitis has yet been established, although diabetes mellitus and diseases caused by exocrine insufficiency, such as Pearson syndrome, are the commonest pancreatic complications of mitochondrial diseases. Here, we report 2 cases of mitochondrial disease complicated by pancreatitis as an unusual pancreatic exocrine manifestation. One patient was a 10-year-old girl with mild retardation of psychomotor development who had experienced recurrent pancreatitis since the age of 4years. Chronic progressive external ophthalmoplegia (CPEO) due to m.8344A>G mutation was diagnosed when the patient was 10years old. The other patient was a 28-year-old woman who was diagnosed with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) due to m.3243A>G mutation at 10years of age. She had experienced regular recurrent vomiting since the age of 16 and suffered an episode of critical pancreatitis at 23years. In both cases, no possible etiological, morphological, or genetic factors for pancreatitis were identified, including anomalous pancreaticobiliary duct. A combination therapy of the standard treatment for chronic pancreatitis and supportive therapy for mitochondrial energy production may be beneficial to prevent the recurrence of acute pancreatitis complicating mitochondrial diseases. The pathophysiological mechanism of pancreatitis in mitochondrial disease has not been adequately established; however, our observations suggest that pancreatitis should be included in the list of pancreatic complications of mitochondrial disease.
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Affiliation(s)
- Akihiko Ishiyama
- Department of Child Neurology, National Center Hospital, National Center of Neurology and Psychiatry, Tokyo, Japan
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Lehtonen HJ, Sipponen T, Tojkander S, Karikoski R, Järvinen H, Laing NG, Lappalainen P, Aaltonen LA, Tuupanen S. Segregation of a missense variant in enteric smooth muscle actin γ-2 with autosomal dominant familial visceral myopathy. Gastroenterology 2012; 143:1482-1491.e3. [PMID: 22960657 DOI: 10.1053/j.gastro.2012.08.045] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Revised: 08/13/2012] [Accepted: 08/28/2012] [Indexed: 12/20/2022]
Abstract
BACKGROUND & AIMS Familial visceral myopathy (FVM) is a rare inherited form of myopathic pseudo-obstruction; little is known about the genetic factors that cause this disorder. FVM is characterized by impaired functions of enteric smooth muscle cells, resulting in abnormal intestinal motility, severe abdominal pain, malnutrition, and even death. We searched for genetic factors that might cause this disorder. METHODS We performed whole-exome sequence analysis of blood samples from 2 individuals in a family that had 7 members diagnosed with FVM. Sanger sequencing was used to analyze additional family members and 280 individuals without this disorder (controls). Intestinal tissue samples from 4 patients and 2 controls were analyzed by immunohistochemistry. Functional studies, including immunofluorescence, cell contractility, and actomyosin structure analyses, were performed using CRL-1976 and U2OS sarcoma cell lines. RESULTS Whole-exome sequence analysis of DNA from 2 siblings identified 83 gene variants that were shared between the siblings and considered as possible disease-causing changes. A heterozygous variant, R148S in enteric smooth muscle actin γ-2 (ACTG2), segregated with disease phenotype. Intestinal smooth muscle (muscularis propria) from individuals with FVM had reduced levels of cytoplasmic ACTG2 and abnormal accumulation of the protein into intracellular inclusions compared with controls. Sarcoma cells that expressed exogenous ACTG2(R148S) incorporated reduced amounts of this protein into actin filaments compared with cells expressing ACTG2(wt) (P < .001). ACTG2(R148S) also interfered with actin cytoskeleton organization and the contractile activities of the cells, indicating a dominant-negative effect. These findings, along with the site of the variation in the protein, indicate that ACTG2 R148S interferes with actin filament assembly. CONCLUSIONS We identified the R148S variant in ACTG2 as a cause of FVM in one family. The altered ACTG2 protein appears to aggregate, rather than form actin filaments, in intestinal smooth muscle tissue. This defect could impair contraction of the visceral smooth muscle cells and reduce bowel motility.
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Affiliation(s)
- Heli J Lehtonen
- Department of Medical Genetics, Genome-Scale Biology Research Program, Biomedicum Helsinki, University of Helsinki, Helsinki, Finland
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de Laat P, Koene S, van den Heuvel LPWJ, Rodenburg RJT, Janssen MCH, Smeitink JAM. Clinical features and heteroplasmy in blood, urine and saliva in 34 Dutch families carrying the m.3243A > G mutation. J Inherit Metab Dis 2012; 35:1059-69. [PMID: 22403016 PMCID: PMC3470685 DOI: 10.1007/s10545-012-9465-2] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 02/06/2012] [Accepted: 02/08/2012] [Indexed: 12/21/2022]
Abstract
The m.3243A>G mutation has become known as the MELAS mutation. However, many other clinical phenotypes associated with this mutation have been described,most frequently being Maternally Inherited Diabetes and Deafness (MIDD). The m.3243A>G mutation, can be detected in virtually all tissues, however heteroplasmy differs between samples. Recent reports indicate, a preference to perform mutation analysis in Urinary Epithelial Cells(UEC). To test this, and to study a correlation between the mutational load in different tissues with two mitochondrial scoring systems (NMDAS and NPMDS) we investigated 34 families carrying the m.3243A>G mutation. Heteroplasmy was determined in three non-invasively collected samples,namely leucocytes, UEC and buccal mucosa. We included 127 patients, of which 82 carried the m.3243A>G mutation.None of the children (n011) had specific complaints. In adults(n071), a median NMDAS score of 15 (IQR 10-24) was found. The most prevalent symptoms were hearing loss(68 %), gastro-intestinal problems (59 %), exercise intolerance(54 %) and glucose intolerance (52 %). Ten patients had neurologic involvement. Buccal mucosa had the best correlation with the NMDAS in all adults (r00.437, p<0.001),whereas UEC had the strongest correlation with the NMDAS in severely affected patients (r00.593, p00.002). Heteroplasmy declined significantly with increasing age in all three samples (leucocytes r0-0.705 (p<0.001), UEC r0-0.374 (p00.001), buccal mucosa r0-0.460 (p<0.001). In our cohort of 82 patients, the m.3243A>Gmutation causes a wide variety of signs and symptoms, MIDD being far more prevalent than MELAS. Looking at the characteristics of the three noninvasively available tissues for testing heteroplasmy we confirm that UEC are the preferred sample to test [corrected].
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Affiliation(s)
- Paul de Laat
- Department of Pediatrics, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, Huispost 804, Geert Grooteplein 10, 6500, HB, PO BOX 9101, Nijmegen, The Netherlands.
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