心筋トロポニンT遺伝子変異に伴う家族性肥大型心筋症の分子遺伝学的研究

取得学位 : 博士（医学）, 学位授与番号 : 医博甲第1358号，学位授与年月日：平成11年3月31日,学位授与年：199

Takotsubo cardiomyopathy with marked ST-segment elevation and electrical alternans complicated with hyperglycemic hyperosmolar state

金沢大学医薬保健研究域医学系This is the first report of a case of Takotsubo cardiomyopathy with a hyperglycemic hyperosmolar state (HHS). This case presented with marked ST-segment elevation and electrical alternans, uncommon findings in Takotsubo cardiomyopathy. We believe that hyperosmolarity-induced myocardial dehydration and consequent increase in intracellular calcium concentration may be the mechanism of Takotsubo cardiomyopathy and electrical alternans in HH

Diagnostic usefulness of the post-exercise systolic blood pressure response for the detection of coronary artery disease in patients with diabetes mellitus

金沢大学大学院医学系研究科Patients with diabetes mellitus (DM) often have a positive result on exercise testing despite a normal coronary arteriogram, which indicates that exercise-induced ST depression is not always an accurate indicator of the presence of coronary artery disease (CAD) in such patients. The present study evaluated the usefulness of the post-exercise systolic blood pressure (SBP) response for the detection of CAD in 47 consecutive patients with DM. Significant stenotic lesions were detected by angiography in 25 patients; 18 of these had true positive (TP) exercise testing results, and 7 had false negative (FN) results. No significant stenotic lesions were detected in the remaining 22 patients and of these 10 had true negative (TN) exercise testing results, and 12 had false positive (FP) results. The SBP ratio (SBP after 3 min of recovery divided by the SBP at peak exercise) was significantly higher in patients with coronary stenoses than in those without. Analysis of the relative cumulative frequency revealed that a SBP ratio greater than 0.87 was associated with significant stenoses. The sensitivity, specificity, and accuracy of ST change combined with a SBP ratio greater than 0.87 for detecting stenoses in patients with DM were 68%, 82%, and 74%, respectively. These results suggest that calculating the SBP ratio, in combination with monitoring for ST depression, improves the accuracy of treadmill exercise testing for the detection of CAD in patients with DM

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

Multiple noncoding exons 1 of nuclear receptors NR4A family (nerve growth factor-induced clone B, Nur-related factor 1 and neuron-derived orphan receptor 1) and NR5A1 (steroidogenic factor 1) in human cardiovascular and adrenal tissues

金沢大学医薬保健研究域医学系Objective: Nuclear receptors are involved in a wide variety of functions, including aldosteronogenesis. Nuclear receptor families NR4A [nerve growth factor-induced clone B (NGFIB), Nur-related factor 1 (NURR1) and neuron-derived orphan receptor 1 (NOR1)] and NR2F [chicken ovalbumin upstream promoter-transcription factor 1 (COUP-TFI), COUP-TFII and NR2F6) activate, whereas NR5A1 [steroidogenic factor 1 (SF1)] represses CYP11B2 (aldosterone synthase) gene transcription. The present study was undertaken to elucidate the mechanism of differential regulation of nuclear receptors between cardiovascular and adrenal tissues. Methods: We collected tissues of artery (n = 9), cardiomyopathy muscle (n = 9), heart muscle (noncardiomyopathy) (n = 6), adrenal gland (n = 9) and aldosterone-producing adenoma (APA) (n = 9). 5′-rapid amplification of cDNA ends (RACE) identified transcription start sites. Multiplex reverse-transcription PCR (RT-PCR) determined use of alternative noncoding exons 1 (ANEs). Results: In adrenocortical H295R cells, angiotensin II, KCl or cAMP, all stimulated CYP11B2 transcription and NR4A was upregulated, whereas NR2F and NR5A1 were downregulated. 5′-RACE and RT-PCR revealed four ANEs of NGFIB (NR4A1), three of NURR1 (NR4A2), two of NOR1 (NR4A3) and two of SF1 (NR5A1) in cardiovascular and adrenal tissues. Quantitative multiplex RT-PCR showed NR4A and NR5A1 differentially employed multiple ANEs in a tissue-specific manner. The use of ANEs of NGFIB and NURR1 was significantly different between APA and artery. Changes in use of ANEs of NGFIB and NOR1 were observed between cardiomyopathy and noncardiomyopathy. The NR4A mRNA levels in artery were high compared with cardiac and adrenal tissues, whereas the NR5A1 mRNA level in adrenal tissues was extremely high compared with cardiovascular tissues. Conclusion: NR4A and NR5A1 genes are complex in terms of alternative promoter use. The use of ANEs may be associated with the pathophysiology of the heart and adrenal gland. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

High sensitivity of late gadolinium enhancement for predicting microscopic myocardial scarring in biopsied specimens in hypertrophic cardiomyopathy

金沢大学医薬保健研究域医学系Background: Myocardial scarring can be assessed by cardiac magnetic resonance imaging with late gadolinium enhancement and by endomyocardial biopsy. However, accuracy of late gadolinium enhancement for predicting microscopic myocardial scarring in biopsied specimens remains unknown in hypertrophic cardiomyopathy. We investigated whether late gadolinium enhancement in the whole heart reflects microscopic myocardial scarring in the small biopsied specimens in hypertrophic cardiomyopathy. Methods and Results: Twenty-one consecutive patients with hypertrophic cardiomyopathy who were examined both by cardiac magnetic resonance imaging and by endomyocardial biopsy were retrospectively studied. The right interventricular septum was the target site for endomyocardial biopsy in all patients. Late gadolinium enhancement in the ventricular septum had an excellent sensitivity (100%) with a low specificity (40%) for predicting microscopic myocardial scarring in biopsied specimens. The sensitivity of late gadolinium enhancement in the whole heart remained 100% with a specificity of 27% for predicting microscopic myocardial scarring in biopsied specimens. Quantitative assessments of fibrosis revealed that the extent of late gadolinium enhancement in the whole heart was the only independent variable related to the microscopic collagen fraction in biopsied specimens (β = 0.59, 95% confident interval: 0.15-1.0, p = 0.012). Conclusions: Although there was a compromise in the specificity, the sensitivity of late gadolinium enhancement was excellent for prediction of microscopic myocardial scarring in hypertrophic cardiomyopathy. Moreover, the severity of late gadolinium enhancement was independently associated with the quantitative collagen fraction in biopsied specimens in hypertrophic cardiomyopathy. These findings indicate that late gadolinium enhancement can reflect both the presence and the extent of microscopic myocardial scarring in the small biopsied specimens in hypertrophic cardiomyopathy. © 2014 Konno et al

肥大型及び拡張型心筋症の病態解明: 分子遺伝学的、臨床機能解析的、両アプローチから

548の心筋症家系(肥大型心筋症400家系、拡張型心筋症148家系)に関して、発端者ならびにその家族の臨床所見および遺伝子変異を解析した。肥大型心筋症の遺伝子変異保因者臨床像について特に左室収縮機能に着目した所、ミオシン群75例(心筋ベータミオシン重鎖遺伝子およびミオシン結合蛋白C遺伝子)とトロポニン群75例(心筋トロポニンT遺伝子および心筋トロポニンI遺伝子)では、収縮不全(左室駆出率50%未満)の合併に違いが認められた。40歳以上の症例における収縮不全発症率について、トロポニン群ではミオシン群と比較して有意に発症率が高いことが示された。研究課題/領域番号:19590807, 研究期間(年度):2007–200

肥大型心筋症および類縁疾患の発症・進展・予後に関する分子遺伝疫学的研究

金沢大学医薬保健研究域保健学系本研究では、82名の肥大型心筋症（HCM）症例（男性57.3%、平均年齢55.4歳）を対象として次世代シークエンサーによる遺伝子解析を施行し、44例（54%）で原因遺伝子変異を同定した。全例において心臓MRI所見を解析した結果、ガドリニウム遅延造影（LGE）は60例（73%）に認められ、%LGEの上昇は原因遺伝子変異の存在を予測する独立した因子であった（オッズ比=2.12、p8.1%において、感度=93.2%、特異度=89.5%、陽性的中率=91.1%、陰性的中率=91.9%であった。Cardiac magnetic resonance (CMR) with late gadolinium enhancement (LGE) revealed a variation in the extent of myocardial scarring, a pathological hallmark of hypertrophic cardiomyopathy (HCM). We aimed to investigate whether variations in the extent of LGE in HCM patients can be explained by the presence or absence of disease-causing mutations. We analyzed data from 82 unrelated HCM patients who underwent both LGE-CMR and next-generation sequencing. We identified disease-causing sarcomere gene mutations in 44 cases (54%). The extent of LGE on CMR was an independent factor for predicting mutation-positive HCM (odds ratio 2.12 [95% confidence interval 1.5-3.8], P8.1%) were 93.2%, 89.5%, 91.1%, and 91.9%, respectively.研究課題/領域番号:17K09082, 研究期間(年度):2017-04-01 - 2020-03-31出典：「肥大型心筋症および類縁疾患の発症・進展・予後に関する分子遺伝疫学的研究」研究成果報告書　課題番号17K09082（KAKEN：科学研究費助成事業データベース（国立情報学研究所）） （https://kaken.nii.ac.jp/report/KAKENHI-PROJECT-17K09082/17K09082seika/）を加工して作

肥大型及び拡張型心筋症の病態解明: 分子遺伝学的、臨床機能解析的、両アプローチから

548の心筋症家系(肥大型心筋症400家系、拡張型心筋症148家系)に関して、発端者ならびにその家族の臨床所見および遺伝子変異を解析した。肥大型心筋症の遺伝子変異保因者臨床像について特に左室収縮機能に着目した所、ミオシン群75例(心筋ベータミオシン重鎖遺伝子およびミオシン結合蛋白C遺伝子)とトロポニン群75例(心筋トロポニンT遺伝子および心筋トロポニンI遺伝子)では、収縮不全(左室駆出率50%未満)の合併に違いが認められた。40歳以上の症例における収縮不全発症率について、トロポニン群ではミオシン群と比較して有意に発症率が高いことが示された。研究課題/領域番号:19590807, 研究期間(年度):2007-200