Impact of functional studies on exome sequence variant interpretation in early-onset cardiac conduction system diseases

Aims The genetic cause of cardiac conduction system disease (CCSD) has not been fully elucidated. Whole-exome sequencing (WES) can detect various genetic variants; however, the identification of pathogenic variants remains a challenge. We aimed to identify pathogenic or likely pathogenic variants in CCSD patients by using WES and 2015 American College of Medical Genetics and Genomics (ACMG) standards and guidelines as well as evaluating the usefulness of functional studies for determining them. Methods and Results We performed WES of 23 probands diagnosed with early-onset (<65 years) CCSD and analyzed 117 genes linked to arrhythmogenic diseases or cardiomyopathies. We focused on rare variants (minor allele frequency < 0.1%) that were absent from population databases. Five probands had protein truncating variants in EMD and LMNA which were classified as “pathogenic” by 2015 ACMG standards and guidelines. To evaluate the functional changes brought about by these variants, we generated a knock-out zebrafish with CRISPR-mediated insertions or deletions of the EMD or LMNA homologs in zebrafish. The mean heart rate and conduction velocities in the CRISPR/Cas9-injected embryos and F2 generation embryos with homozygous deletions were significantly decreased. Twenty-one variants of uncertain significance were identified in 11 probands. Cellular electrophysiological study and in vivo zebrafish cardiac assay showed that 2 variants in KCNH2 and SCN5A, 4 variants in SCN10A, and 1 variant in MYH6 damaged each gene, which resulted in the change of the clinical significance of them from “Uncertain significance” to “Likely pathogenic” in 6 probands. Conclusions Of 23 CCSD probands, we successfully identified pathogenic or likely pathogenic variants in 11 probands (48%). Functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants in patients with CCSD. SCN10A may be one of the major genes responsible for CCSD. Translational Perspective Whole-exome sequencing (WES) may be helpful in determining the causes of cardiac conduction system disease (CCSD), however, the identification of pathogenic variants remains a challenge. We performed WES of 23 probands diagnosed with early-onset CCSD, and identified 12 pathogenic or likely pathogenic variants in 11 of these probands (48%) according to the 2015 ACMG standards and guidelines. In this context, functional analyses of a cellular electrophysiological study and in vivo zebrafish cardiac assay might be useful for determining the pathogenicity of rare variants, and SCN10A may be one of the major development factors in CCSD

Assessment of Coronary atherosclerosis in patients with familial hypercholesterolemia by coronary computed tomography angiography

The aims of this study were (1) to determine whether the accumulation of coronary plaque burden assessed with coronary computed tomography angiography (CCTA) can predict future events and (2) to estimate the onset and progression of coronary atherosclerosis in patients with familial hypercholesterolemia (FH). Consecutive 101 Japanese patients with heterozygous FH (men= 52, mean age 56 ± 16years, mean low-density lipoprotein cholesterol 264 ± 58mg/dl) who underwent 64-detector row CCTA without known coronary artery disease were retrospectively evaluated by assigning a score (0 to 5) to each of 17 coronary artery segments according to the Society of Cardiovascular Computed Tomography guidelines. Those scores were summed and subsequently natural log transformed. The periods to major adverse cardiac events (MACE) were estimated using multivariable Cox proportional hazards models. During the follow-up period (median 941days), 21 MACE had occurred. Receiver operating characteristic curve analyses identified a plaque burden score of 3.35 (raw score 28.5) as the optimal cutoff for predicting a worse prognosis. Multivariate Coxregression analysis identified the presence of a plaque score ≥3.35 as a significant independent predictor of MACE (hazard ratio= 3.65; 95% confidence interval 1.32 to 25.84, p<0.05). The regression equations were Y= 0.68. X- 15.6 (r= 0.54, p <0.05) in male and Y= 0.74. X- 24.8 (r= 0.69, p <0.05) in female patients with heterozygous FH. In conclusion, coronary plaque burden identified in a noninvasive, quantitative manner was significantly associated with future coronary events in Japanese patients with heterozygous FH and that coronary atherosclerosis may start to develop, on average, at age 23 and 34years in male and female patients with heterozygous FH, respectively

Impact of Distal Protection with Filter-Type Device on Long-term Outcome after Percutaneous Coronary Intervention for Acute Myocardial Infarction: Clinical Results with Filtrap®.

Aim: Although distal embolization during percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) deteriorates cardiac function, whether distal protection (DP) can improve prognosis is still controversial. We investigated whether a filter-type DP device, Filtrap®, could improve long-term outcomes after PCI for AMI. Method: We studied 164 patients (130 men, mean age: 65.7 years) who underwent PCI. Patients were divided into two groups based on the use of Filtrap®. The occurrence of congestive heart failure (CHF) and major adverse cardiac events (MACE) defined as cardiac death, recurrent AMI, and target vessel revascularization were compared. Result: Between DP (n=53, 41 men, mean age: 65.5 years) and non-DP (n=111, 89 men, mean age: 65.8 years) groups, although there was significantly greater plaque area in the DP group than in the non-DP group, there were no significant differences in coronary reperfusion flow after PCI. Interestingly, patients with CHF in the non-DP group exhibited a higher CK level than those in the DP group. During a 2-year follow-up period, cumulative CHF was significantly lower in the DP group than in the non-DP group (log-rank p=0.018), and there was no significant difference in the MACE rate (log-rank p=0.238). The use of DP device could not predict MACE, but could predict CHF by multivariate analysis (odds ratio=0.099, 95% CI: 0.02–0.42, p=0.005). Conclusion: These results demonstrate that favorable clinical outcomes could be achieved by the filter-type DP device in AMI, particularly in patients with CHF.出版者照会後に全文公

Two genetic variants of CD38 in subjects with autism spectrum disorder and controls

金沢大学医薬保健研究域医学系The neurobiological basis of autism spectrum disorder (ASD) remains poorly understood. Given the role of CD38 in social recognition through oxytocin (OT) release, we hypothesized that CD38 may play a role in the etiology of ASD. Here, we first examined the immunohistochemical expression of CD38 in the hypothalamus of post-mortem brains of non-ASD subjects and found that CD38 was colocalized with OT in secretory neurons. In studies of the association between CD38 and autism, we analyzed 10 single nucleotide polymorphisms (SNPs) and mutations of CD38 by re-sequencing DNAs mainly from a case-control study in Japan, and Caucasian cases mainly recruited to the Autism Genetic Resource Exchange (AGRE). The SNPs of CD38, rs6449197 (p 70; designated as high-functioning autism (HFA)) in the U.S. 104 AGRE family trios, but not with Japanese 188 HFA subjects. A mutation that caused tryptophan to replace arginine at amino acid residue 140 (R140W; (rs1800561, 4693C>T)) was found in 0.6-4.6% of the Japanese population and was associated with ASD in the smaller case-control study. The SNP was clustered in pedigrees in which the fathers and brothers of T-allele-carrier probands had ASD or ASD traits. In this cohort OT plasma levels were lower in subjects with the T allele than in those without. One proband with the T allele who was taking nasal OT spray showed relief of symptoms. The two variant CD38 poloymorphysms tested may be of interest with regard of the pathophysiology of ASD. © 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society

Improved Survival With Favorable Neurological Outcome in Elderly Individuals With Out-of-Hospital Cardiac Arrest in Japan: A Nationwide Observational Cohort Study

Background:There is sparse data regarding the survival and neurological outcome of elderly patients with out-of-hospital cardiac arrest (OHCA).Methods and Results:OHCA patients (334,730) aged ≥75 years were analyzed using a nationwide, prospective, population-based Japanese OHCA database from 2008 to 2012. The overall 1-month survival with favorable neurological outcome (Cerebral Performance Category Scale, category 1 or 2; CPC 1-2) rate was 0.88%. During the study period, the annual 1-month CPC 1-2 rate in whole OHCA significantly improved (0.73% to 0.96%, P for trend <0.001). In particular, outcomes of OHCA patients aged 75 to 84 years and those aged 85 to 94 years significantly improved (0.98% to 1.28%, P for trend=0.01; 0.46% to 0.70%, P for trend <0.001, respectively). However, in OHCA patients aged ≥95 years, the outcomes did not improve. Multivariate logistic regression analysis indicated that younger age, shockable first documented rhythm, witnessed arrest, earlier emergency medical service (EMS) response time, and cardiac etiology were significantly associated with the 1-month CPC 1-2. Under these conditions, elderly OHCA patients who had cardiac etiology, shockable rhythm and had a witnessed arrest had acceptable 1-month CPC1-2 rate; 7.98% in cases where OHCA was witnessed by family, 15.2% by non-family, and 25.6% by EMS.Conclusions:The annual 1-month CPC 1-2 rate after OHCA among elderly patients significantly improved, and the resuscitation of elderly patients in a selected population is not futile