Family-based Whole Exome Sequencing of Autism Spectrum Disorder Reveals Novel De Novo Variants in Korean Population

Objectives

The objective of this family-based whole exome sequencing (WES) is to examine genetic variants of autism spectrum disorder (ASD) in Korean population.

Methods

The probands with ASD and their biological parents were recruited in this study. We ascertained diagnosis based on DSM-5™ criteria, using Autism Diagnostic Observation Schedule and Autism Diagnostic Interview–Revised. We selected probands with typical phenotypes of ASD both in social interaction/communication and repetitive behaviour/limited interest domains, with intellectual disability (IQ < 70), for attaining homogeneity of the phenotypes. First, we performed WES minimum 50× for 13 probands and high-coverage pooled sequencing for their parents. We performed additional WES for 38 trio families, at least 100× depth. De novo mutations were confirmed by Sanger sequencing. All the sequence reads were mapped onto the human reference genome (hg19 without Y chromosome). Bioinformatics analyses were performed by BWA-MEM, Picard, GATK, and snpEff for variant annotation. We selected de novo mutation candidates from probands, which are neither detected in two pooled samples nor both parents.

Results

Fifty-one subjects with ASD (5 females, 40∼175 months, mean IQ 42) and their families were included in this study. We discovered 109 de novo variants from 46 families. Twenty-nine variants are expected to be amino acid changing, potentially causing deleterious effects. We assume CELSR3, MYH1, ATXN1, IDUA, NFKB1, and C4A/C4B may have adverse effect on central nerve system.

Conclusions

We observed novel de novo variants which are assumed to contribute to development of ASD with typical phenotypes and low intelligence in WES study.

Disclosure of interest

This work has been supported by Healthcare Technology R&D project (No: A120029) by Ministry of Health and Welfare, Republic of Korea.

Structural equation modelling for the effect of physical exercise on excessive daytime sleepiness

OBJECTIVES

The present study aimed to examine the effect of physical exercise on excessive daytime sleepiness (EDS) which is a significant public health problem.

STUDY DESIGN

This is a population-based cohort study.

METHODS

We hypothesized that those who engage in regular exercise would have lower chances of dozing in the daytime and examined causal relationships between EDS and known risk factors for EDS using structural equation model (SEM).

RESULTS

We found that causal relationships from both depression and sleep quality to EDS were relatively weaker in those who regularly engage in physical exercise, which resulted in lower chances of having EDS.

CONCLUSION

Regular exercise may play a protective role in EDS prevention.

Human periodontal ligament stem cells suppress T-cell proliferation via down-regulation of non-classical major histocompatibility complex-like glycoprotein CD1b on dendritic cells

BACKGROUND AND OBJECTIVE

Periodontal ligament stem cells (PDLSCs) from the periodontal ligament tissue were recently identified as mesenchymal stem cells (MSCs). The capabilities of PDLSCs in periodontal tissue or bone regeneration have been reported, but their immunomodulatory role in T-cell immune responses via dendritic cells (DCs), known as the most potent antigen-presenting cell, has not been studied. The aim of this study is to understand the immunological function of homogeneous human STRO-1⁺ CD146⁺ PDLSCs in DC-mediated T-cell immune responses to modulate the periodontal disease process.

MATERIAL AND METHODS

We utilized highly purified (> 95%) human STRO-1⁺ CD146⁺ PDLSCs and human bone marrow mesenchymal stem cells (BMSCs). Each stem cell was co-cultured with human monocyte-derived DCs in the presence of lipopolysaccharide isolated from Porphyromonas gingivalis, a major pathogenic bacterium responsible for periodontal disease, in vitro to examine the immunological effect of each stem cell on DCs and DC-mediated T-cell proliferation.

RESULTS

We discovered that STRO-1⁺ CD146⁺ PDLSCs, as well as BMSCs, significantly decreased the level of non-classical major histocompatibility complex glycoprotein CD1b on DCs, resulting in defective T-cell proliferation, whereas most human leukocyte antigens and the co-stimulatory molecules CD80 and CD86 in/on DCs were not significantly affected by the presence of BMSCs or STRO-1⁺ CD146⁺ PDLSCs.

CONCLUSIONS

This study unveiled an immunomodulatory role of STRO-1⁺ CD146⁺ PDLSCs in negatively regulating DC-mediated T-cell immune responses, demonstrating their potential to be utilized in promising new stem cell therapies.

Association between interleukin-27 polymorphisms and pulmonary tuberculosis

OBJECTIVE

To investigate the effect of interleukin (IL) 27 -964A/G, 2095T/G, 4603G/A and 4730T/C gene polymorphisms on the development of pulmonary tuberculosis (PTB), radiographic characteristics and severity.

DESIGN

Differences in the allele and genotype distributions of the -964A/G, 2095T/G, 4603G/A and 4730T/C polymorphisms between 224 PTB patients and 233 healthy controls, between patients with single- and multi-lobe involvement, and between patients with and without cavitation, were investigated. Serum IL-27 concentration was measured using an enzyme-linked immunosorbent assay.

RESULTS

There were no significant differences in the allele or genotype distributions between PTB patients and healthy controls. However, the -964A/A genotype was more prevalent in patients with single-lobe involvement than the -964A/G or -964G/G genotype in patients with multi-lobe involvement (50.0% vs. 31.3%, P = 0.01). There was no difference between patients with and without cavitation (P > 0.05). Serum median IL-27 concentration was significantly higher in patients with single-lobe involvement than in those with multi-lobe involvement (P = 0.03) and in those with -964A/A genotypes than in those with -964A/G or -964G/G genotypes (P = 0.02).

CONCLUSIONS

In terms of serum IL-27 levels, the -964 A/A genotype may be associated with a protective role that prevents the intrapulmonary spread of PTB rather than its development.

Role of confirmatory interferon-gamma release assays in school outbreaks of tuberculosis in South Korea

OBJECTIVE

To investigate the usefulness of confirmatory QuantiFERON(®) (QFT) testing among tuberculin skin test (TST) positive contacts to diagnose latent tuberculous infection (LTBI) in tuberculosis (TB) outbreaks among adolescents.

DESIGN

We used the Korean national claims database to identify the development of active TB disease in relation to initial TST (cut-off 10 mm induration) and subsequent QFT results.

RESULTS

A total of 7475 contacts in 89 schools were divided into four groups: TST- (n = 5714), TST+/QFT+ (n = 534), TST+/QFT- (n = 697) and TST+ only (n = 530). The mean duration of follow-up was 3.9 ± 0.9 years. For contacts with no LTBI treatment (n = 6868), TB incidence rates per 1000 person-years (py) and the adjusted hazard ratio (HR) compared with TST- individuals were as follows: TST+/QFT+, 66.2/1000 py (HR 35.59, 95%CI 14.03-90.31, P < 0.001); TST+ only, 10.1/1000 py (HR 5.16, 95%CI 2.91-9.17, P < 0.001); TST+/QFT-, 4.0/1000 py (HR 2.05, 95%CI 1.05-4.01, P = 0.035); and TST- 2.0/1000 py. The TB progression rate was significantly higher in TST+/QFT+ than in TST+/QFT- individuals (HR 16.82, 95 CI 5.84-48.46, P < 0.001).

CONCLUSION

A confirmatory QFT for TST+ contacts could reduce the number of candidates for LTBI treatment after school TB outbreaks.

Pathway analysis of genome-wide association datasets of personality traits

Although several genome-wide association (GWA) studies of human personality have been recently published, genetic variants that are highly associated with certain personality traits remain unknown, due to difficulty reproducing results. To further investigate these genetic variants, we assessed biological pathways using GWA datasets. Pathway analysis using GWA data was performed on 1089 Korean women whose personality traits were measured with the Revised NEO Personality Inventory for the 5-factor model of personality. A total of 1042 pathways containing 8297 genes were included in our study. Of these, 14 pathways were highly enriched with association signals that were validated in 1490 independent samples. These pathways include association of: Neuroticism with axon guidance [L1 cell adhesion molecule (L1CAM) interactions]; Extraversion with neuronal system and voltage-gated potassium channels; Agreeableness with L1CAM interaction, neurotransmitter receptor binding and downstream transmission in postsynaptic cells; and Conscientiousness with the interferon-gamma and platelet-derived growth factor receptor beta polypeptide pathways. Several genes that contribute to top-ranked pathways in this study were previously identified in GWA studies or by pathway analysis in schizophrenia or other neuropsychiatric disorders. Here we report the first pathway analysis of all five personality traits. Importantly, our analysis identified novel pathways that contribute to understanding the etiology of personality traits.

Utility of an immunotherapy trial in evaluating patients with presumed autoimmune epilepsy

OBJECTIVE

To evaluate a trial of immunotherapy as an aid to diagnosis in suspected autoimmune epilepsy.

METHOD

We reviewed the charts of 110 patients seen at our autoimmune neurology clinic with seizures as a chief complaint. Twenty-nine patients met the following inclusion criteria: (1) autoimmune epilepsy suspected based on the presence of ≥ 1 neural autoantibody (n = 23), personal or family history or physical stigmata of autoimmunity, and frequent or medically intractable seizures; and (2) initiated a 6- to 12-week trial of IV methylprednisolone (IVMP), IV immune globulin (IVIg), or both. Patients were defined as responders if there was a 50% or greater reduction in seizure frequency.

RESULTS

Eighteen patients (62%) responded, of whom 10 (34%) became seizure-free; 52% improved with the first agent. Of those receiving a second agent after not responding to the first, 43% improved. A favorable response correlated with shorter interval between symptom onset and treatment initiation (median 9.5 vs 22 months; p = 0.048). Responders included 14/16 (87.5%) patients with antibodies to plasma membrane antigens, 2/6 (33%) patients seropositive for glutamic acid decarboxylase 65 antibodies, and 2/6 (33%) patients without detectable antibodies. Of 13 responders followed for more than 6 months after initiating long-term oral immunosuppression, response was sustained in 11 (85%).

CONCLUSIONS

These retrospective findings justify consideration of a trial of immunotherapy in patients with suspected autoimmune epilepsy.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that in patients with suspected autoimmune epilepsy, IVMP, IVIg, or both improve seizure control.

MRI findings in autoimmune voltage-gated potassium channel complex encephalitis with seizures: one potential etiology for mesial temporal sclerosis

BACKGROUND AND PURPOSE

Autoimmune voltage-gated potassium channel complex encephalitis is a common form of autoimmune encephalitis. Patients with seizures due to this form of encephalitis commonly have medically intractable epilepsy and may require immunotherapy to control seizures. It is important that radiologists recognize imaging characteristics of this type of autoimmune encephalitis and suggest it in the differential diagnosis because this seizure etiology is likely under-recognized. Our purpose was to characterize MR imaging findings in this patient population.

MATERIALS AND METHODS

MR imaging in 42 retrospectively identified patients (22 males; median age, 56 years; age range, 8-79 years) with seizures and voltage-gated potassium channel complex autoantibody seropositivity was evaluated for mesial and extratemporal swelling and/or atrophy, T2 hyperintensity, restricted diffusion, and enhancement. Statistical analysis was performed.

RESULTS

Thirty-three of 42 patients (78.6%) demonstrated enlargement and T2 hyperintensity of mesial temporal lobe structures at some time point. Mesial temporal sclerosis was commonly identified (16/33, 48.5%) at follow-up imaging. Six of 9 patients (66.7%, P = .11) initially demonstrating hippocampal enhancement and 8/13 (61.5%, P = .013) showing hippocampal restricted diffusion progressed to mesial temporal sclerosis. Conversely, in 6 of 33 patients, abnormal imaging findings resolved.

CONCLUSIONS

Autoimmune voltage-gated potassium channel complex encephalitis is frequently manifested as enlargement, T2 hyperintensity, enhancement, and restricted diffusion of the mesial temporal lobe structures in the acute phase. Recognition of these typical imaging findings may help prompt serologic diagnosis, preventing unnecessary invasive procedures and facilitating early institution of immunotherapy. Serial MR imaging may demonstrate resolution or progression of radiologic changes, including development of changes involving the contralateral side and frequent development of mesial temporal sclerosis.

The association between periodontitis and obstructive sleep apnea: a preliminary study

BACKGROUND AND OBJECTIVE

Periodontitis is becoming a highly prevalent disease worldwide. Obstructive sleep apnea (OSA) is a common disorder that is characterized by repeated disruptions in breathing during sleep, and mouth breathing is a common characteristic among patients with OSA. We aimed to assess the hypothesis that OSA is associated with the onset and progression of periodontal disease.

MATERIAL AND METHODS

This is a cross-sectional study of a total of 687 participants (460 men and 227 women), 47-77 years of age, who were examined between August 2009 and September 2010 as part of the Korean Genome and Epidemiology Study. The participants underwent standard polysomnography, clinical periodontal examination and health-screening examinations. Periodontitis was defined as clinical attachment level (CAL) ≥ 6 mm and probing pocket depth ≥ 4 mm. OSA was determined using the apnea-hypopnea index (AHI), and an AHI score of ≥ 5 was the cut-off used to indicate the presence of OSA.

RESULTS

The results showed that 17.5% of the participants had periodontitis, 46.6% had OSA and 60.0% who were diagnosed with periodontitis had OSA. In our study, old age, male gender, current smoking status, mouth breathing during sleep and high AHI were identified as risk factors for periodontitis. OSA was positively associated with periodontitis [odds ratio (OR) = 1.84, 95% confidence interval (CI) = 1.18-2.87], probing pocket depth (OR = 2.22, 95% CI = 1.30-3.77) and CAL (OR = 1.86, 95% CI = 1.07-3.21) in a dose-response manner. Additionally, OSA was positively associated with periodontitis (OR = 2.51, 95% CI = 1.37-4.62) in subjects ≥ 55 years of age, but not in subjects < 55 years of age.

CONCLUSION

There is a significant association between OSA and periodontal disease. Further research is needed to clarify the causal relationship between the two conditions.

Association between arachidonate 5-lipoxygenase-activating protein (ALOX5AP) and lung function in a Korean population

Arachidonate 5-lipoxygenase-activating protein (ALOX5AP) plays a role in the 5-lipoxygenase (LO) pathway, which includes the LTC(4), LTD(4), LTE(4) and LTB(4). These leukotrienes are known causative factors of asthma, allergy, atopy and cardiovascular diseases. ALOX5AP lacks enzyme activity and acts by helping 5-LO function. In this study, healthy and general subjects who live in rural and urban areas of Korea were tested for the association of ALOX5AP polymorphisms with lung function. Lung function was also estimated by calculating the predicted values for forced expiratory volume in one second (FEV(1) _%PRED) and the proportion of the forced vital capacity exhaled in the first second (FEV(1) /FVC_PRED). The linear regression was adjusted for residence area, gender, age, height and smoking status. The analysis revealed associations between FEV(1) and the single-nucleotide polymorphism (SNP) rs9506352 and the haplotype TCAC (permuted P-value < 0.05). The linkage disequilibrium block that included the significant SNPs overlapped with SNPs that were revealed previously to associate with myocardial infarction and asthma and to affect lung function. This study is the first to demonstrate the association between lung function and ALOX5AP polymorphisms in a healthy and general population.

Gender-specific association of androgenetic alopecia with metabolic syndrome in a middle-aged Korean population

BACKGROUND

Although several previous studies have investigated the association between metabolic syndrome (MetS) and androgenetic alopecia (AGA), the study results have been inconsistent.

OBJECTIVES

The aim of this study was to investigate the relationship between the presence of MetS and AGA according to gender in a middle-aged Korean population.

METHODS

A population-based cross-sectional study was conducted on a sample from the Korean Genome Epidemiology Study. In total, 3408 subjects (1707 men and 1701 women) were enrolled between January 2008 and February 2010. The Norwood classification for men and Ludwig classification for women were used for assessment of the degree of hair loss. Information on components of MetS together with other possible risk factors was collected.

RESULTS

In men, the risk of having Norwood type IV or greater was not increased for subjects with MetS compared with those without MetS. In women, the risk of having Ludwig type I or greater was significantly increased for subjects with MetS compared with those without MetS after controlling for age and smoking status (OR 1.68, 95% CI 1.14-2.48; P=0.01). Similar results were also observed for the number of fulfilled components of MetS [odds ratio (OR) 1.38, 95% confidence interval (CI) 1.00-1.91; P<0.05]. When each component of MetS was considered individually, associations between AGA and all five components of MetS (waist circumference, triglycerides, high-density lipoprotein-C, blood glucose, and blood pressure) were not statistically significant. When multiple regression was used to adjust for age, family history and smoking, there was no significant association between the prevalence of MetS and moderate to severe AGA in the male group. On the contrary, a statistically significant positive association was noted between the prevalence of MetS and AGA in the female group.

CONCLUSIONS

Our analysis of AGA and the prevalence of MetS in a large population-based cohort demonstrated quite different findings compared with previous reports. The different results according to gender suggest that there may be different mechanisms that are yet to be defined between male and female AGA.

Carotid atherosclerosis in patients with untreated chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation.

OBJECTIVE

To evaluate carotid artery intima-media thickness (IMT), high sensitivity C-reactive protein (hsCRP) and their correlation in newly diagnosed untreated patients with COPD.

DESIGN

Post-bronchodilator spirometry, carotid artery IMT and blood tests were measured in patients with COPD (COPD group). Age, sex, body mass index, smoking status and smoking amount were compared with matched healthy subjects (non-COPD group). Participants taking medications and/or with a history of hypertension, diabetes mellitus, dyslipidaemia, COPD or cardiovascular disease were excluded.

RESULTS

A total of 126 patients (COPD group 42, non-COPD group 84) were enrolled. The IMT and hsCRP of the COPD group were significantly higher than in the non-COPD group (P < 0.05). The decrease in the forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratio and FEV(1) was significantly correlated with an increase in the hsCRP and IMT (P < 0.05); there was no correlation between the IMT and hsCRP (P = 0.152).

CONCLUSION

In newly diagnosed untreated patients with COPD, the carotid artery IMT and hsCRP were significantly higher than in healthy subjects. These findings suggest that systemic inflammation may play a potential role in preclinical atherosclerosis in COPD.

Association of coronary artery calcification with obstructive sleep apnea and obesity in middle-aged men

BACKGROUND AND AIMS

Obstructive sleep apnea (OSA) and obesity are closely associated, and both have been reported to increase the risk of coronary heart disease. Although obesity is known to be associated with coronary artery calcification (CAC), there is limited information on whether OSA is associated with CAC independent of obesity.

METHODS AND RESULTS

A cross-sectional study examined the association between OSA and CAC among 258 healthy men, ages 40-49 years old, randomly selected from a population-based cohort. All individuals underwent overnight polysomnography and electron-beam computed tomography to measure their apnea-hypopnea index (AHI) and degree of CAC. A logistic regression model including potential cardiovascular risk factors excluding body mass index (BMI) showed that the presence of CAC was significantly greater in the fourth quartile versus the first quartile of AHI severity (odds ratio [OR] 2.21, 95% confidence interval [CI] 1.01-4.86). A multivariate linear regression model excluding BMI also showed that AHI was significantly associated with CAC (P = 0.004). However, this association was no longer significant after adjusting for BMI.

CONCLUSIONS

In our cross-sectional study, even though both OSA and obesity were positively associated with the presence and extent of CAC, only obesity remained a significant independent contributor after an adjustment for potential cardiovascular risk factors, irrespective of OSA.

Immune regulatory effects of simvastatin on regulatory T cell-mediated tumour immune tolerance

Statins are potent inhibitors of hydroxyl-3-methylglutaryl co-enzyme A (HMG-CoA) reductase, and have emerged as potential anti-cancer agents based on preclinical evidence. In particular, compelling evidence suggests that statins have a wide range of immunomodulatory properties. However, little is known about the role of statins in tumour immune tolerance. Tumour immune tolerance involves the production of immunosuppressive molecules, such as interleukin (IL)-10, transforming growth factor (TGF)-beta and indoleamine-2,3-dioxygenase (IDO) by tumours, which induce a regulatory T cell (T(reg)) response. In this study, we investigated the effect of simvastatin on the production of IL-10, TGF-beta and IDO production and the proliferation of T(regs) using several cancer cell lines, and Lewis lung cancer (3LL) cells-inoculated mouse tumour model. Simvastatin treatment resulted in a decrease in the number of cancer cells (3LL, A549 and NCI-H292). The production of the immune regulatory markers IL-10, TGF-beta in 3LL and NCI-H292 cells increased after treatment with simvastatin. The expression of IDO and forkhead box P3 (FoxP3) transcription factor was also increased in the presence of simvastatin. In a murine 3LL model, there were no significant differences in tumour growth rate between untreated and simvastatin-treated mice groups. Therefore, while simvastatin had an anti-proliferative effect, it also exhibited immune tolerance-promoting properties during tumour development. Thus, due to these opposing actions, simvastatin had no net effect on tumour growth.

Non-synonymous single-nucleotide polymorphisms associated with blood pressure and hypertension

In this study, we determined the association of 1180 non-synonymous single-nucleotide polymorphisms (SNPs) with systolic blood pressure (SBP) and hypertensive status. A total of 8842 subjects were taken from two community-based cohorts--Ansung (n=4183) and Ansan (n=4659), South Korea--which had been established for genome-wide association studies (GWAS). Five SNPs (rs16835244, rs2286672, rs6265, rs17237198 and rs7312017) were significantly associated (P-values: 0.003-0.0001, not corrected for genome-wide significance) with SBP in both cohorts. Of these SNPs, rs16835244 and rs2286672 correlated with risk for hypertension. The rs16835244 SNP replaces Ala288 in arginine decarboxylase (ADC) with serine, and rs2286672 replaces Arg172 in phospholipase D2 (PLD2) with cysteine. A comparison of peptide sequences between vertebrate homologues revealed that the SNPs identified occur at conserved amino-acid residues. In silico analysis of the protein structure showed that the substitution of a polar residue, serine, for a non-polar alanine at amino-acid residue 288 affects a conformational change in ADC, and that Arg172 in PLD2 resides in the PX domain, which is important for membrane trafficking. These results provide insights into the function of these non-synonymous SNPs in the development of hypertension. The study investigating non-synonymous SNPs from GWAS not only by statistical association analysis but also by biological relevance through the protein structure might be a good approach for identifying genetic risk factors for hypertension, in addition to discovering causative variations.