Morc2a variants cause hydroxyl radical-mediated neuropathy and are rescued by restoring GHKL ATPase.

Mutations in the Microrchidia CW-Type Zinc Finger 2 (MORC2) GHKL ATPase module cause a broad range of neuropathies, such as Charcot-Marie-Tooth disease type 2Z; however, the aetiology and therapeutic strategy are not fully understood. Previously, we reported that the Morc2a p.S87L mouse model exhibited neuropathy and muscular dysfunction through DNA damage accumulation. In the present study, we analysed the gene expression of Morc2a p.S87L mice and designated the primary causing factor. We investigated the pathological pathway using Morc2a p.S87L mouse embryonic fibroblasts and human fibroblasts harbouring MORC2 p.R252W. We subsequently assessed the therapeutic effect of gene therapy administered to Morc2a p.S87L mice. This study revealed that Morc2a p.S87L causes a protein synthesis defect, resulting in the loss of function of Morc2a and high cellular apoptosis induced by high hydroxyl radical levels. We considered the Morc2a GHKL ATPase domain as a therapeutic target because it simultaneously complements hydroxyl radical scavenging and ATPase activity. We used the adeno-associated virus (AAV)-PHP.eB serotype, which has a high central nervous system transduction efficiency, to express Morc2a or Morc2a GHKL ATPase domain protein in vivo. Notably, AAV gene therapy ameliorated neuropathy and muscular dysfunction with a single treatment. Loss of functional characteristics due to protein synthesis defects in Morc2a p.S87L was also noted in human MORC2 p.S87L or p.R252W variants, indicating the correlation between mouse and human pathogenesis. In summary, CMT2Z is known as an incurable genetic disorder, but the present study demonstrated its mechanisms and treatments based on established animal models. This study demonstrates that the Morc2a p.S87L variant causes hydroxyl radical-mediated neuropathy, which can be rescued through AAV-based gene therapy.

Germinal centers are associated with postthymectomy myasthenia gravis in patients with thymoma.

BACKGROUND AND PURPOSE: Germinal centers (GCs) can be observed in the thymic tissues of patients with thymoma-associated myasthenia gravis (MG). Although an association between thymic GCs and MG has been suggested, it is unknown whether the presence of GCs could predict the development of MG after the resection of thymoma, known as postthymectomy MG. METHODS: We conducted a retrospective analysis of previously nonmyasthenic patients who underwent surgical removal of the thymoma. All available thymic tissue slides were rereviewed by a pathologist to assess for GCs. Patients were classified into GC-positive and GC-negative groups based on the presence of GCs. The incidence of postthymectomy MG was compared between the two groups, and the risk factors for postthymectomy MG were assessed. RESULTS: Of the 196 previously nonmyasthenic patients who underwent thymoma resection, 21 were GC-positive, whereas 175 were GC-negative. Postthymectomy MG developed in 11 (5.6%) patients and showed a higher incidence in the GC-positive group than in the GC-negative group (33.3% vs. 2.3%, p < 0.001). No postoperative radiotherapy and the presence of GCs were risk factors for postthymectomy MG in the univariate analysis. In multivariate analysis, invasive thymoma (hazard ratio [HR] = 9.835, 95% confidence interval [CI] = 1.358-105.372), postoperative radiotherapy (HR = 0.160, 95% CI = 0.029-0.893), and presence of GCs (HR = 15.834, 95% CI = 3.742-67.000) were significantly associated with postthymectomy MG. CONCLUSIONS: Thymic GCs may be a significant risk factor for postthymectomy MG. Even in patients with thymoma who do not show clinical symptoms of MG, postthymectomy MG should be considered, especially if thymic GCs are observed.

In vivo genome editing using 244-cis LNPs and low-dose AAV achieves therapeutic threshold in hemophilia A mice.

Gene therapy and rebalancing therapy have emerged as promising approaches for treating hemophilia A, but there are limitations, such as temporary efficacy due to individual differences. Genome editing for hemophilia has shown long-term therapeutic potential in preclinical trials. However, a cautious approach is necessary because genome editing is irreversible. Therefore, we attempted to induce low-level human factor 8 (hF8) gene knockin (KI) using 244-cis lipid nanoparticles and low-dose adeno-associated virus to minimize side effects and achieve a therapeutic threshold in hemophilia A mice. We selected the serpin family C member 1, SerpinC1, locus as a target to enable a combined rebalancing strategy with hF8 KI to augment efficacy. This strategy improved blood coagulation activity and reduced hemophilic complications without adverse effects. Furthermore, hemophilic mice with genome editing exhibit enhanced survival for 40 weeks. Here, we demonstrate an effective, safe, and sustainable treatment for hemophilia A. This study provides valuable information to establish safe and long-term genome-editing-mediated treatment strategies for treating hemophilia and other protein-deficient genetic diseases.

Development and Application of a Cell-Based Assay for LRP4 Antibody Associated With Myasthenia Gravis.

BACKGROUND AND PURPOSE: Among patients with double-seronegative myasthenia gravis (dSN-MG) who do not have detectable antibodies against acetylcholine receptor or muscle-specific tyrosine kinase, autoantibodies against low-density lipoprotein receptor-related protein 4 (LRP4-Ab) have been detected recently. The purpose of this study was to develop an in-house cell-based assay (CBA) to detect LRP4-Ab and to apply it to samples from patients with MG. METHODS: The complementary DNA of LRP4 fused into a vector plasmid containing GFP was transfected into human embryonic kidney 293 (HEK293) cells. LRP4 expression in the transfected HEK293 cells was assessed using the reverse-transcription polymerase chain reaction (RT-PCR), Western blotting, and immunocytochemistry. The CBA included 252 sera collected from 202 patients with MG and 38 with other neuromuscular diseases, and 12 healthy controls. The transfected HEK293 cells were incubated using sera and antihuman immunoglobulin G antibodies conjugated with Alexa Fluor 594. The presence of LRP4-Ab was determined based on the fluorescence intensity and the localization in fluorescence microscopy. RESULTS: The expressions of the mRNA and protein of LRP4 in the transfected HEK293 cells were confirmed using RT-PCR and Western blotting, respectively. Immunocytochemistry indicated LPR4 expression on the cell membrane. Among 202 patients with MG including 53 with dSN-MG, LRP4-Ab were positive in 3 patients who were all double seronegative. LRP4-Ab were not detected in the patients with other neuromuscular diseases or the healthy controls. CONCLUSIONS: A CBA for detecting LRP4-Ab associated with MG has been developed, and was used to find LRP4-Ab in the sera of patients with MG.

Anti-titin antibodies are associated with myocarditis in patients with myasthenia gravis.

BACKGROUND: Myasthenia gravis (MG) can affect cardiac muscles with variable presentations. Myocarditis is a rare but potentially serious cardiac manifestation of MG. Although thymomas and anti-titin antibodies have been suggested as risk factors for myocarditis in patients with MG, their independent influence on myocarditis has rarely been assessed. METHODS: A retrospective chart review was conducted on 247 patients diagnosed with MG who were tested for anti-titin antibodies. Myocarditis was diagnosed on the basis of the European Society of Cardiology 2013 Task Force criteria for clinically suspected myocarditis. Patients were classified into myocarditis-positive and myocarditis-negative groups. Multivariate analysis was performed to analyze the risk factors for myocarditis. RESULTS: Of the 247 patients, 25 (10.1%) were myocarditis-positive and 222 (89.9%) were myocarditis-negative. Anti-titin antibody positivity was higher in the myocarditis-positive group than in the myocarditis-negative group (68.0% vs. 28.4%, p < 0.001). A history of MG crisis was more frequent in the myocarditis-positive group than in the myocarditis-negative group (64.0% vs. 10.4%, p < 0.001). The presence of anti-titin antibodies (odds ratio [OR] 7.906; confidence interval [CI] 2.460-25.401) and MG crisis (OR 24.807; CI 7.476-82.311) was significantly associated with myocarditis. The Cox regression model showed that the anti-titin antibody levels (hazard ratio [HR] 3.639; 95% CI 1.557-8.505) and MG crisis (HR 6.137; 95% CI 2.639-14.272) were significant risk factors for the development of myocarditis. CONCLUSION: The presence of anti-titin antibody was associated with myocarditis in patients with MG, whereas thymoma was not. Although rare, early suspicion of myocarditis could be required, especially in patients with MG having anti-titin antibodies.

Anti-titin antibody is associated with more frequent hospitalization to manage thymoma-associated myasthenia gravis.

Background and purpose: Anti-titin antibodies are antistriational antibodies associated with thymoma-associated myasthenia gravis (MG). We evaluated whether the patients with anti-titin antibody are more frequently hospitalized to manage thymoma-associated MG than those patients without anti-titin antibody. Methods: Patients with thymoma-associated MG who conducted the serological test for anti-titin antibody were retrospectively included. Disease severity, treatments, MG-related annual hospitalization rate, and MG-related emergency room (ER) visit rate were compared between the patients with anti-titin antibody and those patients without anti-titin antibody. Multivariate analysis was conducted to analyze the association between anti-titin antibody serostatus and multiple admissions (hospitalization or ER visit of ≥2 times). Results: Of the 64 included patients, 31 (48.4%) patients were positive for anti-titin antibody (titin+ group) and 33 (51.6%) patients were negative for anti-titin antibody (titin- group). Both the annual rate of MG-related hospitalization and ER visit were significantly higher in the titin+ group [0.2 (0.1-0.6) and 0.1 (0-0.2) per year, respectively] than those in the titin- group [0 (0-0.2) and 0 (0-0) per year, p = 0.004 and p = 0.006, respectively]. In multivariate analysis, positive anti-titin antibody was still significantly associated with multiple admissions [odds ratio (OR) 4.11, 95% CI 1.05-16.03] compared to the titin- group as a reference after adjusting for sex, follow-up duration, age at onset, systemic chemotherapy, and the Masaoka staging. Conclusion: The presence of anti-titin antibody is associated with more frequent hospital utilization. Personalized explanation and careful monitoring strategy could be required in patients with thymoma-associated MG with anti-titin antibody for the timely detection of relapses.

Frequency of fetal-maternal microchimerism: an analysis of the HLA-DRB1 gene in cord blood and maternal sample pairs.

PURPOSE: We aimed to investigate the frequency of fetal-maternal microchimerism among cord blood (CB) from a Korean population. MATERIALS AND METHODS: We previously developed a nested polymerase chain reaction-single-strand conformation polymorphism method for microchimerism detection that is highly sensitive (0.01-0.001%) and specific. We used this method to investigate the frequency of fetal-maternal HLA-DRB1 microchimerism among 153 maternal and 152 CB samples. RESULTS: Among the tested pairs, 41.1% exhibited at least one direction of microchimerism, 32.0% of the mothers possessed fetal microchimerism, and 23.4% of the newborns possessed maternal microchimerism. The overall microchimerism frequency was 28.2%. CONCLUSIONS: We hypothesize that the different microchimerism frequencies among population and methods are due to differences in detection specificities and subject characteristics. This study provides basic data on fetal-maternal microchimerism that may be useful for future studies on autoimmune disorder and virtual phenotyping in transplantation.

Genomic Profile of Chronic Lymphocytic Leukemia in Korea Identified by Targeted Sequencing.

Chronic lymphocytic leukemia (CLL) is extremely rare in Asian countries and there has been one report on genetic changes for 5 genes (TP53, SF3B1, NOTCH1, MYD88, and BIRC3) by Sanger sequencing in Chinese CLL. Yet studies of CLL in Asian countries using Next generation sequencing have not been reported. We aimed to characterize the genomic profiles of Korean CLL and to find out ethnic differences in somatic mutations with prognostic implications. We performed targeted sequencing for 87 gene panel using next-generation sequencing along with G-banding and fluorescent in situ hybridization (FISH) for chromosome 12, 13q14.3 deletion, 17p13 deletion, and 11q22 deletion. Overall, 36 out of 48 patients (75%) harbored at least one mutation and mean number of mutation per patient was 1.6 (range 0-6). Aberrant karyotypes were observed in 30.4% by G-banding and 66.7% by FISH. Most recurrent mutation (>10% frequency) was ATM (20.8%) followed by TP53 (14.6%), SF3B1 (10.4%), KLHL6 (8.3%), and BCOR (6.25%). Mutations of MYD88 was associated with moderate adverse prognosis by multiple comparisons (P = 0.055). Mutation frequencies of MYD88, SAMHD1, EGR2, DDX3X, ZMYM3, and MED12 showed similar incidence with Caucasians, while mutation frequencies of ATM, TP53, KLHL6, BCOR and CDKN2A tend to be higher in Koreans than in Caucasians. Especially, ATM mutation showed 1.5 fold higher incidence than Caucasians, while mutation frequencies of SF3B1, NOTCH1, CHD2 and POT1 tend to be lower in Koreans than in Caucasians. However, mutation frequencies between Caucasians and Koreans were not significantly different statistically, probably due to low number of patients. Collectively, mutational profile and adverse prognostic genes in Korean CLL were different from those of Caucasians, suggesting an ethnic difference, while profile of cytogenetic aberrations was similar to those of Caucasians.

Association of human leukocyte antigen with postherpetic neuralgia in Koreans.

Postherpetic neuralgia (PHN), the most frequent complication of varicella-zoster virus reactivation, is characterized by pain that persists for more than 3 months, often for years after healing of zoster rash. A few studies revealing the association of human leukocyte antigen (HLA) with PHN have been reported, but only in the Japanese. The aim of this study was to investigate the primary HLA locus associated with PHN susceptibility in Koreans. We compared HLA-A, -B, -C, and DRB1 genotypes of 66 PHN patients with those of 54 herpes zoster (HZ) patients without developing PHN and 235 healthy controls. Frequencies of HLA-B*13, B*44, B*15 (B75), DRB1*10:01, and DRB1*12:02 were increased, and those of HLA-C*01, C*12, and DRB1*01:01 were decreased in PHN patients compared to those in controls (each, p < 0.05). Among these alleles, only the frequency of HLA-B*44 was significantly increased in PHN patients compared to that in HZ patients and the change was due to HLA-B*44:03 (PHN vs controls, p = 0.043; PHN vs HZ, p = 0.012). The results suggest that HLA-B*44:03 or other closely linked gene of the major histocompatibility complex is associated with susceptibility to the development of PHN after HZ, but not with the onset of HZ.

Relationship between personality disorder dimensions and verbal memory functioning in a community population.

Based on the Baltimore Epidemiologic Catchment Area (ECA) follow-up survey, we examined relationships between dimensions of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) personality disorders and both subjective and objective memory functioning in a community population. Our study subjects consisted of 736 individuals from the ECA follow-up study of the original Baltimore ECA cohort, conducted between 1993 and 1996 and available for assessment in the Hopkins Epidemiology Study of Personality Disorders from 1997 to 1999. Subjects were assessed for DSM-IV personality disorders using a semi-structured instrument, the International Personality Disorder Examination, and were asked about a subjective appraisal of memory. Verbal memory function, including immediate recall, delayed recall, and recognition, were also evaluated. Multiple linear regression analyses were used to determine associations between personality dimensions of DSM-IV Axis II traits and subjective and objective memory functioning. Scores on schizoid and schizotypal personality dimensions were associated with subjective and objective memory dysfunction, both with and without adjustment for Axis I disorders. Borderline, antisocial, avoidant, and dependent personality disorder scores were associated with subjective memory impairment only, both with and without adjustment for Axis I disorders. This study suggests that subjective feelings of memory impairment and/or objective memory dysfunction are associated with specific personality disorder dimensions.

Detection of HLA-DRB1 microchimerism using nested polymerase chain reaction and single-strand conformation polymorphism analysis.

For the detection of microchimerism, molecular methods detecting donor-specific HLA-DRB1 alleles in the recipient are most commonly used. Nested polymerase chain reaction sequence specific primer (nested PCR-SSP) methods widely used to increase the sensitivity of detection have been reported to give frequent false-positive reactions. We have developed a new method combining nested PCR with single-strand conformation polymorphism analysis (nested PCR-SSCP) and tested the 1 to 0.00001% level of microchimerism for 27 different HLA-DRB1 alleles. For most (26/27) of the HLA-DRB1 alleles tested, this method could detect 0.01 to 0.001% of microchimerism and its sensitivity was equal to or better than that of nested PCR-SSP tested in parallel. Its specificity was verified by visualizing particular DRB1-specific SSCP bands under test. Nested PCR-SSP indicated frequent false-positive reactions, mainly caused by nonspecific amplification of DRB3/B4/B5 alleles present in the major (recipient) DNAs. We have compared a real-time quantitative PCR for non-human leukocyte antigen (HLA) target (insertion/deletion marker) using a commercial kit (AlleleSEQR Chimerism assay), and its microchimerism detection sensitivity (around 0.1%) was 1 step (10 times) lower than that of nested PCR-SSP or -SSCP methods for HLA-DRB1 alleles. We validated that the newly designed nested PCR-SSCP affords good sensitivity and specificity and may be useful for studying microchimerism in clinical settings.

[Discrepancies between human leukocyte antigen registry typing and confirmatory typing results of unrelated hematopoietic stem cell donors].

BACKGROUND: In unrelated hematopoietic stem cell transplantation, the accuracy of HLA registry typing (RT) of donors is important for timely search and coordination of HLA-matched donors. We analyzed discrepancies between HLA RT and confirmatory typing (CT) results of stem cell donors in Korean and foreign registries. METHODS: We analyzed the HLA typing results of 834 donors for whom CT was performed at Seoul National University Hospital between April 1997 and March 2010. For CT, DNA typing was used in majority of the cases and HLA-A and HLA-B serological typing was used in some early cases. The discrepancies between the typing results were analyzed at the serological/generic level. RESULTS: The overall discrepancy rate (RT error rate) was 3.2%, and the rate was similar in the Korean and foreign registries. The discrepancy rates in the Korean and foreign registries were more than 10% in the 1997-2001 searches, but decreased to less than 3% in the 2002-2010 searches. Analysis of 19 cases of RT errors in the Korean registry revealed 3 cases of sample switchover errors and 16 cases of typing errors in one of the HLA-A, HLA-B, or HLA-DR loci. The RT error rate in Japan Marrow Donor Program was lower than those in other foreign registries. CONCLUSIONS: The error rate of HLA RT results of unrelated stem cell donors in the Korean registry was similar to those in the foreign registries, and has decreased in the recent searches following the change in the typing method from serological to DNA typing.

[Allelic and haplotypic diversity of HLA-A, -B, -C, and -DRB1 genes in Koreans defined by high-resolution DNA typing].

BACKGROUND: In this study, we used high-resolution DNA typing to investigate the distribution of HLA alleles and haplotypes in Koreans. METHODS: HLA-A, -B, -C, and -DRB1 alleles were genotyped at the allelic (4-digit) level in 474 healthy Koreans. HLA genotyping was performed in two steps. Initially, serologic typing or generic-level DNA typing was performed using the PCR-sequence-specific oligonucleotide method, and then allelic DNA typing (exons 2 and 3 for class I, and exon 2 for DRB1) was carried out using the PCR-single-strand conformation polymorphism method or sequence-based typing. HLA allele and haplotype frequencies and linkage disequilibrium values were calculated by the maximum likelihood method using a computer program developed for the 11th International Histocompatibility Workshop. RESULTS: A total of 21 HLA-A, 40 HLA-B, 22 HLA-C, and 29 HLA-DRB1 alleles were found in Koreans. The most frequent alleles in each locus with frequencies of ≥ 10% were, in decreasing order of frequency, as follows: A*24:02, A*02:01, A*33:03; B*51:01; C*01:02, C*03:03; and DRB1*09:01. The numbers of two- and three-locus haplotypes with frequencies of >0.5% were as follows: 44 A-C, 42 B-C, 51 A-B, 52 B-DRB1, 42 A-C-B, and 34 A-B-DRB1. Thirteen A-B-DRB1 haplotypes with frequencies of ≥ 1.0% comprised 26.0% of the total haplotypes. The six most common haplotypes were as follows: A*33:03-B*44:03-DRB1*13:02 (3.7%), A*33:03-B*44:03-DRB1*07:01 (3.0%), A*33:03-B*58:01-DRB1*13:02 (3.0%), A*24:02-B*07:02-DRB1*01:01 (2.8%), A*30:01-B*13:02-DRB1*07:01 (2.3%), and A*11:01-B*15:01-DRB1*04:06 (2.2%). CONCLUSIONS: The information obtained in this study can be used as basic data for Koreans in the fields of organ transplantation, disease association, and anthropologic studies.

Association among aggressiveness, neurocognitive function, and the Val66Met polymorphism of brain-derived neurotrophic factor gene in male schizophrenic patients.

BACKGROUND: The aim of this study was to investigate the association among aggressive behavior, neuropsychological function, and the Val66Met functional polymorphism of brain-derived neurotrophic factor (BDNF) gene in male schizophrenic patients. METHODS: We examined 51 male patients with schizophrenia who had committed homicide (ie, H-SCZ), 50 male patients with schizophrenia who had not committed homicide (ie, NH-SCZ), and 50 healthy male controls. Patients were evaluated using the Positive and Negative Syndrome Scale, Life History of Aggression, and the Overt Aggression Scale. In addition, patients were given neurocognitive function tests, including Korean-Wechsler Adult Intelligence Scale short form, the Korean version of the Rey Memory Test, the Stroop Test, and the Wisconsin Card Sorting Test. The Val66Met polymorphism of the BDNF gene was also genotyped in all schizophrenic patients. RESULTS: We observed no significant difference between patients in the H-SCZ and NH-SCZ groups, with regard to Positive and Negative Syndrome Scale scores. Total Life History of Aggression (P < .01) and Overt Aggression Scale scores for the most severe episode (P < .01) or for the previous month (P < .05) were higher in the H-SCZ group than in the NH-SCZ group. There were no significant differences in the genotype distribution or allelic frequency of the Val66Met polymorphism between the schizophrenic groups. In addition, we observed no significant differences between H-SCZ and NH-SCZ groups with regard to performance on neuropsychological tests. The Met allele of the Val66Met polymorphism was associated with poor intelligence quotient, memory quotient), learning, and delayed recall in the H-SCZ group. However, genotype did not seem to influence neurocognitive function in schizophrenic patients who had committed homicide. CONCLUSIONS: The neurocognitive tests used in our study were unable to distinguish between violent and nonviolent schizophrenic patients. Furthermore, the Val66Met polymorphism was not associated with aggressiveness in patients with schizophrenia.

[Comparison of the rate of detection of immunoglobulin heavy chain gene rearrangement by fluoresecence in situ hybridization probes in multiple myeloma.].

BACKGROUND: Immunoglobulin heavy chain (IgH) gene rearrangement, which is frequently observed in multiple myeloma, can now be detected easily by using a fluorescence in situ hybridization (FISH) method. The aim of this study was to determine the detection rate and compare the utility of the three most commonly used probes: IGH/CCND1 dual color, dual fusion probe; IGH/BCL2 dual color, dual fusion probe; and IGH dual color break apart rearrangement probe; all from Vysis Products (Downers Grove, IL, USA). METHODS: From October 1994 to July 2003, 99 patients were diagnosed as multiple myeloma at Seoul National University Hospital, Asan Medical Center and Gachon University Gil hospital. We applied the three different probes of IgH FISH on bone marrow specimens from the 99 Korean patients with multiple myeloma to detect IgH gene rearrangement. RESULTS: Forty-one (41.4%) of the 99 patients had IgH gene rearrangement. Of those 41 patients, 23 (56.1%) showed positive to all three probes, but the remaining 18 (43.9%) showed a discrepancy between the three probes: 13 (72.2%) of the 18 patients were only positive to the IGH dual color break apart rearrangement probe and the detection rate was 39.6% on the average. CONCLUSIONS: These results demonstrate that IGH dual color break apart rearrangement probe is superior to the other two probes in qualitative and quantitative ways. Thus, we recommend IGH dual color break apart rearrangement probe for the diagnosis and monitoring of multiple myeloma.