INTRODUCTION 1. The necessity of this study Schizophrenia is a group of severe psychosis, characterized by psychotic symptoms such as delusions, hallucinations, catatonia, disorganized speech and behavior. The symptoms of schizophrenia are varied and they always change over time [1]. In the world, there are tens of millions of people with schizophrenia, accounting for about 1% of the world''s population. Every year, this rate increases by 0.15% of the population. Prevalence of schizophrenia in Vietnam is 0.3-0.8%, and every year it increases by 0.1-0.15% of the population[2]. For decades, many authors have focused on the etiology and pathogenesis of schizophrenia according to several trends such as genetics [9], [10]...neurotransmitters [21], [22]...environmental factors [19], [20]...Each schizophrenia theory is characterized by its advantages and limitations. Although many studies on schizophrenia have been conducted in Vietnam, most of them have just described the clinical symptoms, progression and treatment of schizophrenia. Few studies have researched on EEG, but they still restricted, especially about the feature of EEG in schizophrenia. Many studies of molecular, genetic and gene change in schizophrenia in the world [1], [2] have concerned of gene Catechol-O-methyltransferase and Zinc-finger protein 804A) [13], [14], but number of studies on nucleotide polymorphisms in schizophrenia has been limited in Vietnam. In previous decades, studies on the etiology and pathogenesis of schizophrenia, including EEG and schizophrenic genetic, have faced many difficulties and hassles, both in terms of technical procedures and equipment, which are not suitable to the current situation in Vietnam. Nowadays, because of new techniques and methods in quantitative electroencephalography [49], [50] and new generation sequencing [15], in-depth studies of EEG and molecular genetic in schizophrenia become available. Therefore, the “Research on features of electroencephalogram and some polymorphisms of COMT, ZNF804A gene in patients with schizophrenia” has been launched with two objectives as follows: 1/ To describe EEG and relationship between EEG and clinical features in patients with schizophrenia. 2/ To assess the frequency of allele and genotypic distribution of ZNF804A gene polymorphism rs1344706 and COMT gene polymorphism rs165599 in patients with schizophrenia.
1 INTRODUCTION The necessity of this study Schizophrenia is a group of severe psychosis, characterized by psychotic symptoms such as delusions, hallucinations, catatonia, disorganized speech and behavior The symptoms of schizophrenia are varied and they always change over time [1] In the world, there are tens of millions of people with schizophrenia, accounting for about 1% of the world's population Every year, this rate increases by 0.15% of the population Prevalence of schizophrenia in Vietnam is 0.3-0.8%, and every year it increases by 0.1-0.15% of the population[2] For decades, many authors have focused on the etiology and pathogenesis of schizophrenia according to several trends such as genetics [9], [10] neurotransmitters [21], [22] environmental factors [19], [20] Each schizophrenia theory is characterized by its advantages and limitations Although many studies on schizophrenia have been conducted in Vietnam, most of them have just described the clinical symptoms, progression and treatment of schizophrenia Few studies have researched on EEG, but they still restricted, especially about the feature of EEG in schizophrenia Many studies of molecular, genetic and gene change in schizophrenia in the world [1], [2] have concerned of gene Catechol-Omethyltransferase and Zinc-finger protein 804A) [13], [14], but number of studies on nucleotide polymorphisms in schizophrenia has been limited in Vietnam In previous decades, studies on the etiology and pathogenesis of schizophrenia, including EEG and schizophrenic genetic, have faced many difficulties and hassles, both in terms of technical procedures and equipment, which are not suitable to the current situation in Vietnam Nowadays, because of new techniques and methods in quantitative electroencephalography [49], [50] and new generation sequencing [15], in-depth studies of EEG and molecular genetic in schizophrenia become available Therefore, the “Research on features of electroencephalogram and some polymorphisms of COMT, ZNF804A gene in patients with schizophrenia” has been launched with two objectives as follows: 1/ To describe EEG and relationship between EEG and clinical features in patients with schizophrenia 2/ To assess the frequency of allele and genotypic distribution of ZNF804A gene polymorphism rs1344706 and COMT gene polymorphism rs165599 in patients with schizophrenia Practical significance and new contributions - This has been the first systematic study on clinical features which initially assessed on the EEG and ZNF804A gene rs1344706 polymorphism, COMT gene polymorphism rs165599 in patients with schizophrenia in Vietnam - The analysis of EEG was successfully applied by EEGLab sofware running on Matlab in schizophrenic patients - EEG changes in patients with schizophrenia were varied: Amplitude of alpha wave, delta wave and theta wave had statistically significant differences between two groups and recording channels The energy property of alpha wave in schizophrenia group was significantly lower than in control group The energy property of delta wave and theta wave in schizophrenia group were significantly higher than in control group EEG frequency did not change in schizophrenic patients, comparing to control group There was a correlation between hallucinations and EEG in patients with schizophrenia, including: increase of amplitude, energy properties of alpha, delta, and theta waves - The frequency of allele rs1344706 polymorphism in schizophrenic patients was 53.30% (A) and 46.70% (C), and the distribution of three genotypes AA, CC and AC in patients with schizophrenia was 28.19%, 21.59% and 50.22% Whereas, frequency of allele A and G of rs165599 polymorphism in schizophrenia patients was 51.32% and 48.68%; and the distribution of genotypes AA, GG and AG were 22.75%, 25.11% and 47.14%, respectively There was no difference in allele frequency and genotypic distribution of rs1344706 and rs165599 polymorphism between schizophrenia and control group There was also no difference in allele frequency and genotypic distribution between two groups in both females and males - This research opened a new direction for early diagnosis as well as tools to support the diagnosis and evaluation of treatment results in patients with schizophrenia Structure of thesis Thesis was written in 152 pages, tables and figures The content includes: Introduction (2 pages); Chapter 1: Over view (38 pages); Chapter 2: Objects and methods (18 pages); Chapter 3: Result (46 pages); Chapter 4: Discussion (26 pages) and conclusion (2 pages); Recommendation (1 page); List of research projects that publish results of the thesis page; References (18 page) (Vietnamese documents and foreign languages documents) CHAPTER OVERVIEW 1.1 Concept of schizophrenia Schizophrenia is characterized by many disturbances such as thinking disorder, emotional and behavioral disorder These symptoms include: positive symptoms such as delusions, hallucinations, and catatonia; negative symptoms such as: flat affect, asociality, avolition, anhedonia, and alogia [5] 1.2 Electroencephalogram in schizophrenia Previous studies have shown the changes of alpha wave, delta wave and theta wave in schizophrenia in terms of amplitude, power, frequency, and reactivity Especially, there are the appearance of waves with frequency 25-35 Hz and low amplitude, as called "choppy" EEG changes in schizophrenia occur in 64% of patients Nowadays, researches have been focusing on analyzing the EEG in schizophrenia in terms of energy and output property 1.3 Changes in ZNF804A and COMT gene, in schizophrenia 1.3.1 ZNF804A gene and schizophrenia ZNF804 is a gene encoding the ZNF804A protein in humans, located on chromosome q32.1, consisting of exons, encoding proteins with 1210 amino acids In humans, ZNF804A is widely expressed in the brain, particularly in the developing hippocampus and cortex, as well as the cerebellum in adults A study of GWAS identified ZNF804A as a sensitive gene of schizophrenia From the genealogical studies of schizophrenia , it is said that genetic coefficient is nearly 80% The rs1344706 polymorphism in intron of the ZNF804A gene has been identified as the single polymorph ism which is most closely associated with schizophrenia Recent evidences also have shown that the ZNF804A gene may be one of the most potential genes which relate in schizophrenia [1] 1.3.2 The rs1344706 Polymorphism and schizophrenia The relationship between rs1344706 polymorphism and schizophrenia is widely recognized and reached a consensus [85] The association between ZNF804A and schizophrenia, especially rs1344706 polymorphism, has been confirmed by many researches on European samples However, these results have not been consistent among Asians [86] 1.3.3 COMT gene and schizophrenia COMT gene has a schizophrenia-related region on chromosome 22; contains important fragments 22q11.2; related to catecholamine metabolism: group of neurotransmitters involved in mental disorders and psychiatric treatment Relationship of the COMT gene rs4680 polymorphism related to females in schizophrenia was found in a study (p = 0.02) [108], [109] Another studies of COMT gene also showed the relationship between schizophrenia and environmental risk factors such as marijuana stimulant use to schizophrenia [110], [111], [112] 1.3.4 The rs165599 polymorphism and schizophrenia The rs165599 polymorphism, which has received much attention in schizophrenia researches, suggests it has a role to play This polymorphism, which plays a role in increasing dopamine, has explained some of the features of schizophrenia, including delusions, hallucinations, disorganized speech and behavior This role is also shown in the association of alleles with schizophrenia at the age of onset and the decrease in working productivity [116] 1.4 Research on Electroencephalogram and genes in schizophrenia in Vietnam Schizophrenia is one of the leading causes of disability, often onset at a young age, with severe consequences for patients, families and society In the world, researches on changing EEG and genetic features in schizophrenia have been interested in many respects However, schizophrenia has been highly concerned about epidemiology and clinical features in Vietnam There have also been some studies evaluating EEG in schizophrenia, but these studies have just assessed through subjective evaluation Extensive and in-depth assessments of specific functional areas related to high-level functional disorders as well as studies of genetic and polymorphic traits, including ZNF804A and COMT gene in Vietnamese, have been still unclear Researches on EEG and genes in schizophrenia in the world still have showed many different results Therefore, research on these issues in Vietnamese population is new and necessary CHAPTER OBJECT AND METHOD 2.1 Study objects The schizophrenia group includes 230 patients with schizophrenia diagnosed according to criteria of World Health Organization in 1992 (ICD-10F) These patients was treated at the Department of Psychiatry, Military Hospital 103, Vietnamese Military Medical University The control group includes 94 healthy people who suitable for age, gender and some other conditions with above patients 2.2 Methods 2.2.1 Study design A Cross-sectional follow-up study includes analysis of clinical symptoms of patients corresponding to COMT, ZNF804A gene and EEG changes in the schizophrenia group 2.2.2 Clinical research method Clinical research method is to directly interview with patients and their family members to collect information about the patient's history 2.2.3 Electroencephalogram analysing method EEGLab v13.4.4b analysis software running on MatLab 2017 software Procedure of EEG analysis was conducted at Diagnostic Imaging Department-103 Military Hospital-Vietnam Military Medical University 2.2.4 Research method of genetic polymorphism The ZNF804A gene polymorphism rs1433706 was determined by the direct sequencing method and the COMT gene polymorphism rs165599 was determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method Process of conducting these techniques to determine the polymorphisms: Military Pharmaceutical Research Centre-Vietnam Military Medical University Chapter RESULTS 3.1 General features of study subjects Table 3.1 Distributon by age group of two groups < 20 Schizophrenic group n (%) 25 (10.87) Control group n (%) 10 (10.64) 20-29 93 (40.43) 45 (47.87) 30-39 61 (26.52) 22 (23.40) 40-50 35 (15.22) 13 (13.83) > 50 16 (6.96) 04 (4.26) Mean age 31.24± 0.97 31.02±10.40 Age group p > 0.05 > 0.05 The result in Table 3.1 showed that there was the similarity about the number and prevalence by age group of two groups (p>0.05) There was a significant difference on distribution by age group between each age range band in two groups (p 0.05 The result in the Table 3.2 showed that there was a similarity between two groups (p>0.05) The result also illustrated that prevalence was higher in subjects of male than those of female (p