GROWTH RATE OF PARAGANGLIOMAS RELATED TO GERMLINE MUTATIONS OF THE SDHX GENES.

OBJECTIVE: The purpose was to determine the growth rate of succinate dehydrogenase subunit (SDHx) gene-related paragangliomas based on computed tomography (CT) measurements. METHODS: Twenty-seven patients with SDHx mutations who underwent subsequent CT examinations were enrolled in the study. Tumors were classified as head and neck (HNP), thoracic, or abdominal/pelvic paragangliomas (PGLs). The percentage volume increase and volume doubling time were estimated. RESULTS: We analyzed 56 PGLs (21 with SDHD, 6 with SDHB mutations) in 27 patients (16 men, 11 women; mean age 37.7 years). The estimated median of the follow-up was 23 months. Twenty-two (39.3%) PGLs were located in the abdomen, 8 (14.3%) in the thorax, and 26 (46.4%) in the head and neck region. The median volume growth rate was estimated at 10.4% per year (interquartile range [IQR]: -1.3; 36.3). The volume doubling time was estimated as 7.01 (2.24;+∞) years. By tumor site, the estimated medians of the annual volume growth rates were 13.6% (IQR:0.8 -30.4) for HNP, -6.06% (IQR: -1.79;47.32) for thoracic PGLs, and 10.5% (IQR: -2.2;44.6) for abdominal PGLs. The volume doubling time was 5.44 years (2.61; 87.0) for HNP, 11.8 years (1.79;+∞) for thoracic PGLs, and 6.94 years (1,88;+∞) for abdominal PGLs. There was no significant difference in the volume growth rate according to tumor location or initial size (P>.7 and P = .07, respectively) or gene mutation type (SDHB vs. SDHD, P>.8). CONCLUSION: PGLs related to SDHx mutations are slowly growing tumors. There were no correlations between tumor location, growth rate or initial size over a 23-month follow-up period. ABBREVIATIONS: CT = computed tomography HNP = head and neck paraganglioma IQR = interquartile range PGL = paraganglioma PPGL = pheochromocytoma and paraganglioma SDH = succinate dehydrogenase.

Coexistence of Andersen-Tawil Syndrome with Polymorphisms in hERG1 Gene (K897T) and SCN5A Gene (H558R) in One Family.

BACKGROUND: Andersen-Tawil Syndrome (ATS) is a channelopathy caused by mutations in KCNJ2 gene. It is characterized by symptoms of ventricular arrhythmias, periodic paralysis or muscle weakness, and dysmorphic features. ATS can present with the triad of symptoms, any combination or none of them. Risk factors for dangerous arrhythmias are unknown. The study assessed the impact of K897T polymorphism in hERG1 gene and H558R polymorphism in SCN5A gene coexisting with R218Q mutation in KCNJ2 in one family on clinical manifestation. METHODS: Family members underwent clinical assessment, ECG and genotyping. Holter monitoring was performed in mutation carriers and additionally in one family member with no mutation, but with K897T polymorphism. RESULTS: Proband with ATS mutation, K897T and H558R polymorphisms and proband's sister with ATS mutation and K897T polymorphism presented following symptoms: loss of consciousness, bidirectional and polymorphic ventricular tachycardia and about 5000 ventricular extrasystoles. Symptoms presented by the member with only the ATS mutation and by member with ATS mutation and H558R polymorphism were not as severe. U wave appeared in all examined family members regardless of the mutation presence. Studied individuals with ATS mutation had the T-peak-U-peak interval longer than 200 ms. In all ATS mutation carriers it was longer than in family members with no mutation. T-peak-T-end interval was the longest (>120 ms) in members with coexisting mutation and K897T polymorphism. CONCLUSION: ATS severity possibly depends on other genes' polymorphisms. In the presented family, it could depend on the presence of K897T polymorphism in hERG1.

Evaluation of Head and Neck Paragangliomas by Computed Tomography in Patients with Pheochromocytoma-Paraganglioma Syndromes.

BACKGROUND: Hereditary head and neck paragangliomas (HNP) are very often associated with pheochromocytoma-paraganglioma syndromes, which are caused by mutations in genes encoding subunits of succinate dehydrogenase (SDHx) complex. The aim of this study was to determine the frequency and location of HNP among SDHx carriers. MATERIAL/METHODS: A total of 72 patients with SDHx mutations underwent computed tomography examinations of the head and neck. HNP were present in 44 (61.1%) out of 72 patients (31 SDHD, 11 SDHB, 2 SDHC); 113 HNP were found; the most common were carotid paragangliomas (59) and vagal paragangliomas (27). RESULTS: The HNP were statistically more frequent in carriers of SDHD mutations compared to carriers of SDHB mutations (72.1% vs. 43.5%, p=0.033). Multiple tumors more often occurred in patients with SDHD mutations 26/31 (83.9%) than in patients with SDHB mutations 6/11 (54.5%) p=0.05. There was a significant difference in the prevalence of carotid paragangliomas between patients with SDHB and SDHD mutations (7/11 [63.6%] vs. 30/31 [96.8%], respectively, p=0.004). Patients with SDHD mutations more often had carotid paragangliomas located on the left side than on the right side, as compared to SDHB mutations 25/31 (80.6%) vs. 4/11 (36.4%), p=0.006. CONCLUSIONS: SDHx mutations predispose to multifocal and bilateral HNP. Carotid and vagal paragangliomas occurred most often. Patients with SDHD mutations are characterized by higher frequency of HNP than patients with SDHB mutations, which is mainly driven by higher frequency of carotid body tumors in patients with SDHD mutations. No difference in the frequency of head and neck paragangliomas in other locations was found.

Usefulness of Somatostatin Receptor Scintigraphy (Tc-[HYNIC, Tyr3]-Octreotide) and 123I-Metaiodobenzylguanidine Scintigraphy in Patients with SDHx Gene-Related Pheochromocytomas and Paragangliomas Detected by Computed Tomography.

AIMS: The aim of this study was to assess the usefulness of somatostatin receptor scintigraphy (SRS) using (99m)Tc-[HYNIC, Tyr3]-octreotide (TOC) and 123I-metaiodobenzylguanidine (mIBG) in patients with SDHx-related syndromes in which paragangliomas were detected by computed tomography and to establish an optimal imaging diagnostic algorithm in SDHx mutation carriers. METHODS: All carriers with clinical and radiological findings suggesting paragangliomas were screened by SRS and 123I-mIBG. Lesions were classified by body regions, i.e. head and neck, chest, abdomen with pelvis and adrenal gland as well as metastasis. RESULTS: We evaluated 46 SDHx gene mutation carriers (32 index cases and 14 relatives; 28 SDHD, 16 SDHB and 2 SDHC). In this group, 102 benign tumors were found in 39 studied patients, and malignant disease was diagnosed in 7 patients. In benign tumors, the sensitivity of SRS was estimated at 77% and of 123I-mIBG at 22.0%. The SRS and mIBG sensitivity was found to be clearly region dependent (p < 0.001). The highest SRS sensitivity was found in head and neck paragangliomas (HNP; 91.4%) and the lowest was found in abdominal paragangliomas and pheochromocytomas (40 and 42.9%, respectively). The highest 123I-mIBG sensitivity was found in pheochromocytomas (sensitivity of 100%) and the lowest in HNP (sensitivity of 3.7%). In metastatic disease, SRS was superior to mIBG (sensitivity of 95.2 vs. 23.8%, respectively). CONCLUSION: SRS and 123I-mIBG single photon emission computed tomography (SPECT) sensitivity in SDHx patients is highly body region dependent. In malignant tumors, SRS is superior to 123I-mIBG SPECT.

Associations of the eNOS G894T gene polymorphism with target organ damage in children with newly diagnosed primary hypertension.

BACKGROUND: The endothelial nitric oxide synthase (eNOS) G894T gene polymorphism is associated with the risk of primary hypertension (PH) and vascular complications in adults with PH. METHODS: We explored the associations of the G894T polymorphism with 24-h ambulatory blood pressure, left ventricular mass (LVM), carotid intima media thickness (cIMT), urinary albumin excretion, oxidative stress and inflammatory parameters in 126 children with newly diagnosed PH and in 83 healthy children. RESULTS: Among the 126 children with PH 92 (73%) had ambulatory hypertension and 34 (27%) had severe ambulatory hypertension. Left ventricular hypertrophy (LVH) was detected in 39 (31%) patients, cIMT of >2 standard deviation scores in 21 (16.6%) patients, albuminuria of >30 mg/24 h in 18 (14.3%) patients and metabolic syndrome (MS) in 22 (17.5%) patients. The frequency of the T allele was 52.4% in the PH group and 54.2% in the control group (not significant), and in both groups the frequency of the T allele was consistent with the Hardy-Weinberg equilibrium. Compared with G allele carriers, hypertensive T allele carriers had increased cIMT (p < 0.05) and more severe albuminuria (not significant, p = 0.1); there was no difference between the groups in hypertension severity and LVM. T and G allele distribution did not differ between patients with and without metabolic syndrome. No significant correlations between the assessed parameters and the eNOS G894T gene polymorphism were found in the controls, although T allele carriers tended to have an increased cIMT (p = 0.09). CONCLUSION: The eNOS T allele is not more prevalent among hypertensive children than among healthy ones, but it is associated with early vascular damage in children with PH, independent of metabolic abnormalities. No associations between the eNOS G894T polymorphism and metabolic abnormalities were found.

Outcomes of adrenal-sparing surgery or total adrenalectomy in phaeochromocytoma associated with multiple endocrine neoplasia type 2: an international retrospective population-based study.

BACKGROUND: The prevention of medullary thyroid cancer in patients with multiple endocrine neoplasia type 2 syndrome has demonstrated the ability of molecular diagnosis and prophylactic surgery to improve patient outcomes. However, the other major neoplasia associated with multiple endocrine neoplasia type 2, phaeochromocytoma, is not as well characterised in terms of occurrence and treatment outcomes. In this study, we aimed to systematically characterise the outcomes of management of phaeochromocytoma associated with multiple endocrine neoplasia type 2. METHODS: This multinational observational retrospective population-based study compiled data on patients with multiple endocrine neoplasia type 2 from 30 academic medical centres across Europe, the Americas, and Asia. Patients were included if they were carriers of germline pathogenic mutations of the RET gene, or were first-degree relatives with histologically proven medullary thyroid cancer and phaeochromocytoma. We gathered clinical information about patients'RET genotype, type of treatment for phaeochromocytoma (ie, unilateral or bilateral operations as adrenalectomy or adrenal-sparing surgery, and as open or endoscopic operations), and postoperative outcomes (adrenal function, malignancy, and death). The type of surgery was decided by each investigator and the timing of surgery was patient driven. The primary aim of our analysis was to compare disease-free survival after either adrenal-sparing surgery or adrenalectomy. FINDINGS: 1210 patients with multiple endocrine neoplasia type 2 were included in our database, 563 of whom had phaeochromocytoma. Treatment was adrenalectomy in 438 (79%) of 552 operated patients, and adrenal-sparing surgery in 114 (21%). Phaeochromocytoma recurrence occurred in four (3%) of 153 of the operated glands after adrenal-sparing surgery after 6-13 years, compared with 11 (2%) of 717 glands operated by adrenalectomy (p=0.57). Postoperative adrenal insufficiency or steroid dependency developed in 292 (86%) of 339 patients with bilateral phaeochromocytoma who underwent surgery. However, 47 (57%) of 82 patients with bilateral phaeochromocytoma who underwent adrenal-sparing surgery did not become steroid dependent. INTERPRETATION: The treatment of multiple endocrine neoplasia type 2-related phaeochromocytoma continues to rely on adrenalectomies with their associated Addisonian-like complications and consequent lifelong dependency on steroids. Adrenal-sparing surgery, a highly successful treatment option in experienced centres, should be the surgical approach of choice to reduce these complications.

Pheochromocytoma presenting as takotsubo-like cardiomyopathy following delivery.

OBJECTIVE: Diagnosis of pheochromocytoma during pregnancy can be difficult, and the tumor carries an unfavorable prognosis if not diagnosed and treated in a timely manner. METHODS: To present a case of Takotsubo-like cardiomyopathy characterized by transient left ventricular apical ballooning due to pheochromocytoma following delivery. RESULTS: A few hours after Caesarean section, a 32-year-old Caucasian female presented with pulmonary edema followed by cardiac arrest with echocardiographic and ventriculographic evidence of reversible acute myocardial failure characteristic of Takotsubo-like cardiomyopathy. A previously unrecognized adrenal pheochromocytoma was found during her clinical work-up. Left ventricle (LV) function normalized after surgical removal of the tumor, which was carried out after implementing an alpha-adrenoreceptor blockade. Hemorrhagic necrosis of the pheochromocytoma was seen on histopathologic analysis; this may have triggered the sequence of events leading to the development of Takotsubo-like cardiomyopathy and hemodynamic collapse. CONCLUSION: To the best of our knowledge, this is the first reported case of Takotsubo-like cardiomyopathy related to pheochromocytoma following delivery. This emphasizes the increased cardiovascular risk if pheochromocytoma is not diagnosed and treated in a timely manner, especially during pregnancy.

Impact of genetic and clinical factors on dose requirements and quality of anticoagulation therapy in Polish patients receiving acenocoumarol: dosing calculation algorithm.

BACKGROUND: Despite the recent emergence of new oral anticoagulants, vitamin K antagonists remain the primary therapy in patients with atrial fibrillation and the only therapy licensed for use in patients with artificial heart valves. OBJECTIVE: The aim of this study was (a) to assess the impact of clinical and genetic factors on acenocoumarol (AC) dose requirements and the percentage of time in therapeutic range (%TTR) and (b) to develop pharmacogenetic-guided AC dose calculation algorithm. MATERIALS AND METHODS: We included 235 outpatients of the Institute of Cardiology (Warsaw), mean age 69.3, 46.9% women, receiving AC for artificial heart valves and/or atrial fibrillation. A multiple linear-regression analysis was performed using log-transformed effective AC dose as the dependent variable, and combining CYP2C9 and VKORC1 genotyping with other clinical factors as independent predictors. RESULTS: We identified factors that influenced the AC dose: CYP2C9 polymorphisms (P=0.004), VKORC1 polymorphisms (P<0.0001), age (P<0.0001), creatinine clearance lower than 40 ml/min (P=0.035), body mass (P=0.02), and dietary vitamin K intake (P=0.026). Clinical and genetic factors explained 49.0% of AC dose variability. We developed a dosing calculation algorithm that is, to the best of our knowledge, the first one to assess the effect of such clinical factors as creatinine clearance and dietary vitamin K intake on the AC dose. The clinical usefulness of the algorithm was assessed on separate validation group (n=50) with 70% accuracy. Dietary vitamin K intake higher than 200 mcg/day improved international normalized ratio control (%TTR 73.3±17 vs. 67.7±18, respectively, P=0.04). CONCLUSION: Inclusion of a variety of genetic and clinical factors in the dosing calculation algorithm allows for precise AC dose estimation in most patients and thus improves the efficacy and safety of the therapy.

Pathogenic variants in plakophilin-2 gene (PKP2) are associated with better survival in arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is mainly caused by mutations in genes encoding desmosomal proteins. Variants in plakophilin-2 gene (PKP2) are the most common cause of the disease, associated with conventional ARVC phenotype. The study aims to evaluate the prevalence of PKP2 variants and examine genotype-phenotype correlation in Polish ARVC cohort. All 56 ARVC patients fulfilling the current criteria were screened for genetic variants in PKP2 using denaturing high-performance liquid chromatography or next-generation sequencing. The clinical evaluation involved medical history, electrocardiogram, echocardiography, and follow-up. Ten variants (5 frameshift, 2 nonsense, 2 splicing, and 1 missense) in PKP2 were found in 28 (50%) cases. All truncating variants are classified as pathogenic/likely pathogenic, while the missense variant is classified as variant of uncertain significance. Patients carrying a PKP2 mutation were younger at diagnosis (p = 0.003), more often had negative T waves in V1-V3 (p = 0.01), had higher left ventricular ejection fraction (p = 0.04), and were less likely to present symptoms of heart failure (p = 0.01) and left ventricular damage progression (p = 0.04). Combined endpoint of death or heart transplant was more frequent in subgroup without PKP2 mutation (p = 0.03). Pathogenic variants in PKP2 are responsible for 50% of ARVC cases in the Polish population and are associated with a better prognosis. ARVC patients with PKP2 mutation are less likely to present left ventricular involvement and heart failure symptoms. Combined endpoint of death or heart transplant was less frequent in this group.

Polymorphisms of the beta-1 and beta-2 adrenergic receptors in Polish patients with idiopathic dilated cardiomyopathy.

BACKGROUND: Dilated cardiomyopathy (DCM) is a disorder characterised by dilation and impaired contractility of the left or both ventricles. This multifactorial disease has a strong genetic component with familial occurrence. A number of genes have been associated with idiopathic DCM (IDCM) including beta-1 (b1-AR) and beta-2 (b2-AR) adrenergic receptors. b1-AR and b2-AR are G-coupled proteins which play an important role in the regulation of heart rate and cardiac contractility. The beta-adrenergic receptor pathway is altered in heart failure. Recent studies have discovered functionally relevant and common polymorphisms in both b1-AR and b2-AR. AIM: We investigated the frequency of the b1-AR (Ser49Gly, Arg389Gly) and b2-AR (Arg16Gly, Gln27Glu, Thr164Ile) polymorphisms in patients with IDCM in comparison to controls in the Polish population. METHODS: We used a case-control study design comparing a series of consecutive, unrelated 97 IDCM patients with 105 healthy blood donors. Polymorphisms were determined by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP). RESULTS: There was no significant difference in relation to genotype distribution and allele frequencies of any analysed b1-AR and b2-AR polymorphisms between IDCM patients and controls. The analysis of polymorphism associations did not reveal a higher frequency of coexisting b2-AR Gly16Gln27, Gly16Glu27 and Arg16Gln27 genotypes alone or in combination with the b1-AR Arg389 allele in IDCM. CONCLUSION: Our data showed that the studied beta-adrenergic receptor polymorphisms did not seem to play a significant role in IDCM in the Polish population.

Alterations in calcium regulatory protein expression in patients with preserved left ventricle systolic function and mitral valve stenosis.

BACKGROUND: In heart failure, alterations in the expression of proteins relevant to calcium homeostasis are involved in depressed contractility and diminished relaxation. However the regulation of genes expression is only partially known. The aim was to assess expression of calcium regulatory proteins in left ventricle (LV) myocardium characterised by a preserved global function in mitral valve stenosis (MVS) model but increased neurohumoral/cytokine (N/C) activation. METHODS AND RESULTS: Plasma N/C activation was evaluated in MVS-patients (n = 27), where expression of calcium regulatory proteins (L-type channel, sarcoplasmic reticulum Ca2+-ATPase type2 - SERCA2, Na+/Ca2+ exchanger -NCX, calsequestrin, phospholamban) in LV myocardium was assessed (Western Blot) in comparison with non-failing hearts (NFH). Out of all proteins assessed in MVS, only SERCA2 and NCX expression revealed highly variable changes between subjects, with significant reduction of SERCA2 (15%) level compared to NFH. Moreover, SERCA2 was negatively correlated with BNP (univariate/regression analysis r = -0.63, P = 0.005/r2 = 0.74, P <0.001, respectively), whereas NCX was positively correlated only with noradrenaline (univariate/stepwise analysis r = 0.59 P = 0.002/r2 = 0.59; P = 0.003). CONCLUSIONS: In MVS-patients LV becomes remodelled, although its global function is preserved. It seems that apart from alterations in LV load and wall stress, also such neurohumoral factors as BNP/noradrenaline may influence the Ca2+ handling proteins expression.

Genetic variants in hypertensive patients with coronary artery disease and coexisting atheromatous renal artery stenosis.

BACKGROUND: Atheromatous renal artery stenosis (ARAS) often coexists with coronary artery disease (CAD). This study evaluated the prevalence of three polymorphisms: angiotensin-converting enzyme (ACE) insertion/deletion (Ins/Del), endothelial nitric oxide synthase (eNOS) Glu298Asp, and methylenetetrahydrofolate reductase (MTHFR) C677T, in hypertensive patients referred for coronary and renal angiography. MATERIAL/METHODS: The study included 223 hypertensive patients divided into three groups: 72 patients without significant CAD or evidence of ARAS, 111 patients with significant CAD but no ARAS, and 40 patients with coexisting significant CAD and evidence of ARAS. The control group consisted of 195 age- and sex-matched healthy subjects. RESULTS: Patients with coexisting significant CAD and evidence of ARAS were older (p=0.03), less frequently obese (p=0.02), and more likely to have peripheral carotid or femoral artery disease (PAD) (p=0.02) compared with patients with significant CAD but no ARAS. They differed in terms of ACE Del/Del genotype distribution (40% vs. 17.1%, respectively, p=0.007). In a multivariate analysis the independent predictors of ARAS were PAD (OR: 3.7, 95%CI: 1.1-12.3, p=0.005) and ACE Del/Del polymorphism (OR: 3.3, 95%CI: 1.3-8.2, p=0.01). There was a higher prevalence of eNOS Asp/Asp genotype in all patients with significant CAD than in controls (9.3% vs. 3.6%, respectively, p=0.02), but no difference in MTHFR polymorphism between the studied groups was found. CONCLUSIONS: In the hypertensive population referred for coronary and renal angiography, the ACE insertion/deletion variant but not eNOS Glu298Asp or MTHFR C677T polymorphism, seems to coexist with atheromatous renal artery stenosis.

Identification novel LQT syndrome-associated variants in Polish population and genotype-phenotype correlations in eight families.

Congenital long QT syndrome (LQTS) is a primary cardiac channelopathy. Genetic testing has not only diagnostic but also prognostic and therapeutic implications. At present, 15 genes have been associated with the disease, with most mutations located in 3 major LQTS-susceptibility genes. During a routine genetic screening for KCNQ1, KCNH2 and SCN5A genes in index cases with LQTS, seven novel variants in KCNH2 and SCN5A genes were found. Genotype-phenotype correlations were analysed in these patients and their families. An open reading frame and splice site analysis of the exons was conducted using next-generation sequencing. In novel variants, phenotypes of carriers and their affected relatives were analysed. In 39 unrelated patients, 40 pathogenic/putative pathogenic mutations were found. Thirty-three of them, predominantly missense, were reported previously: 11 were in the KCNQ, 17 in the KCNH2 and 5 in the SCN5A gene. Seven novel missense variants were found in eight families. Among them, four variants were in typical for LQTS location. Two variants in the KCNH2 gene (p.D803Y and p.D46F) and one in the SCN5A gene (G1391R) were in amino acid (AA) position which up to present has not been reported in LQTS. Phenotype analysis showed the life-threatening course of the disease in index cases with a history of sudden cardiac death in six families. Mutation carriers presented with ECG abnormalities and some of them received beta-blocker therapy. We report three novel variants (KCNQ1 p.46, KCNH2 p.D803Y, SCN5A p.G1391R) which have never been reported for this AA location in LQTS; the phenotype-genotype correlation suggests their pathogenicity.

Alteration of myocardial sarcoplasmic reticulum Ca2+-ATPase and Na+-Ca2+ exchanger expression in human left ventricular volume overload.

BACKGROUND: Reduced myocardial contractility is often attributed to altered Ca(2+) transients and expression of Ca(2+)-ATPase of the SR (SERCA) and Na+/Ca(2+)exchanger (NCX) genes. AIMS: To assess myocardial expression of SERCA and NCX protein levels in left ventricular (LV) remodelling due to chronic severe mitral regurgitation (MR). METHODS: Myocardial expression of SERCA/NCX in biopsy specimens obtained during mitral surgery was assessed in 36 MR patients with LV remodelling and plasma neurohumoral/cytokine activation and in four non-failing hearts (NFH). RESULTS: Myocardial protein levels of SERCA were significantly (20%) lower in the MR group than in NFH group (p=0.016). No significant changes in NCX were observed. However, a lack of homogeneity with regard to SERCA/NCX proteins was observed. Moreover, SERCA was negatively correlated with BNP (r=-0.49, p=0.02), TNFalpha (r=-0.68, p=0.0005) and IL-6 (r=-0.52, p=0.02), whereas NCX was only negatively correlated with TNFalpha (r=-0.62, p=0.002). CONCLUSIONS: MR patients showed wide variations in SERCA/NCX protein expression. Myocardial protein levels of SERCA were significantly lower in the MR population. Moreover, a correlation between BNP, cytokines (IL-6, TNFalpha) and the expression of SERCA/NCX proteins was observed.

Andersen-Tawil syndrome: Clinical presentation and predictors of symptomatic arrhythmias - Possible role of polymorphisms K897T in KCNH2 and H558R in SCN5A gene.

BACKGROUND: Andersen-Tawil syndrome (ATS) is rare channelopathy caused by KCNJ2 mutation and probably KCNJ5. It is characterized by arrhythmias, neurological symptoms, and dysmorphic features. The present study retrospectively examined the characteristics of 11 unrelated families with ATS. METHODS: This study consisted of 11 probands positive for KCNJ2 variants and 33 family members (mean age 30.0±17.3 years, female n=31). Additional genetic screening of 3 LQTS genes (KCNQ1, KCNH2, SCN5A) was performed in 9 families. Predictors of arrhythmias [premature ventricular beats>2000/24h, biventricular and polymorphic ventricular tachycardia (VT)], syncope, and/or cardiac arrest (CA) were evaluated. RESULTS: In KCNJ2 mutation carriers vs non-carriers (n=25 vs n=19) significant differences were observed in U-wave manifestations in V2-V4, Tpeak-Tend duration, QTUc duration (p<0.0001), dysmorphic features, and neurological symptoms. Compared to asymptomatic carriers (n=9), in those with arrhythmias and/or syncope and/or CA (n=16) micrognathia (p=0.004), periodic paralysis (p=0.019), palpitation (p=0.005), U-wave n V2-V4 (p=0.049) were more frequent; QTU (p=0.045) and Tpeak-Tend (p=0.014) were also longer (n=9). In the subgroup of carriers with syncope and/or cardiac arrest (n=10, 90% women), K897T-KCNH2 polymorphism (p=0.02), periodic paralysis (p=0.004), muscle weakness (p=0.04), palpitations (p=0.04), arrhythmias (biventricular VT, p=0.003; polymorphic VT, p=0.009) were observed more frequently. Tpeak-Tend duration was longer (p=0.007) and the percentage of patients with premature ventricular contraction >2000/24h was higher (p=0.005). CONCLUSION: A higher risk of arrhythmia, syncope, and/or CA is associated with the presence of micrognathia, periodic paralysis, and prolonged Tpeak-Tend time. Our findings suggest that K897T may contribute to the occurrence of syncope.

Titin Truncating Variants in Dilated Cardiomyopathy - Prevalence and Genotype-Phenotype Correlations.

TTN gene truncating variants are common in dilated cardiomyopathy (DCM), although data on their clinical significance is still limited. We sought to examine the frequency of truncating variants in TTN in patients with DCM, including familial DCM (FDCM), and to look for genotype-phenotype correlations. Clinical cardiovascular data, family histories and blood samples were collected from 72 DCM probands, mean age of 34 years, 45.8% FDCM. DNA samples were examined by next generation sequencing (NGS) with a focus on the TTN gene. Truncating mutations were followed up by segregation study among family members. We identified 16 TTN truncating variants (TTN trunc) in 17 probands (23.6% of all cases, 30.3% of FDCM, 17.9% of sporadic DCM). During mean 63 months from diagnosis, there was no difference in adverse cardiac events between probands with and without TTN truncating mutations. Among relatives 29 mutation carriers were identified, nine were definitely affected (31%), eight probably affected (27.6%) one possibly affected (3.4%) and eleven were not affected (37.9%). When relatives with all affected statuses were combined, disease penetrance was still incomplete (62.1%) even after exclusion of unaffected relatives under 40 (82%) and was higher in males versus females. In all mutation carriers, during follow-up, 17.4% had major adverse cardiac events, and prognosis was significantly worse in men than in women. In conclusion, TTN truncating variants were observed in nearly one fourth of young DCM patient population, in vast majority without conduction system disease. Incomplete penetrance suggests possible influence of other genetic and/or environmental factors on the course of cardiotitinopathy. Counseling should take into account sex and incomplete penetrance.

Mediastinal paragangliomas related to SDHx gene mutations.

INTRODUCTION: Paragangliomas (PGLs) related to hereditary syndromes are rare mediastinal tumors. Paragangliomas are caused by mutations in genes encoding subunits of succinate dehydrogenase enzyme (SDH). AIM: To evaluate clinical, anatomical and functional characteristics of mediastinal paragangliomas related to SDHx gene mutations. MATERIAL AND METHODS: Retrospective analysis of 75 patients with confirmed SDHx gene mutations (24 patients with SDHB, 5 SDHC, 46 with SDHD mutations) was performed. Patients underwent evaluation using computed tomography (CT), somatostatin receptor scintigraphy (SRS) (99mTc-[HYNIC,Tyr3]-octreotide), 123I mIBG scintigraphy and urinary excretion of total methoxycatecholamines. RESULTS: Out of 75 patients, 16 (21%) patients (1 SDHB, 15 SDHD mutations) had 17 PGLs localized in the mediastinum. Fourteen PGLs were localized in the middle mediastinum (intrapericardial) and 3 PGLs in the posterior mediastinum. The median diameter of paragangliomas measured on the axial slice was 24.3 mm (interquartile range (IQR): 14.7-36.6), and the median volume was 2.78 ml (IQR: 0.87-16.16). Twelve out of 16 patients (75%) underwent SRS, and 11 of them (92.3%) had pathological uptake of the radiotracer. Eleven (68.75%) out of 16 patients underwent 123 I mIBG, with only 3 positive results. Symptoms of catecholamine excretion were observed in 3 patients with PGLs localized in the posterior mediastinum. All PGLs were benign except in 1 patient with the SDHB mutation and PGL detected in the posterior mediastinum, who had a metastatic disease. CONCLUSIONS: Most mediastinal paragangliomas were related to SDHD gene mutations. They were asymptomatic, localized in the medial mediastinum, intrapericardially.

QTc prolongation in patients with hearing loss: Electrocardiographic and genetic study.

BACKGROUND: The aim of the study was to determine, whether electrocardiogram (ECG) screening could reduce the risk of sudden cardiac death in patients with hearing loss through the early diagnosis of Jervell and Lange-Nielsen syndrome and the introduction of the therapy. METHODS: One thousand and eighty patients with hearing loss (aged 21.8 ± 19.9 years) underwent ECG. Additionally, all subjects were asked to complete a 3-question survey. Those who met, at least, one of the high-risk criteria underwent further cardiac assessment and genetic testing. RESULTS: QTc assessment was possible in 1,027 patients. Mean QTc measured 422.8 ± 23.7 ms in 313 women, 414.9 ± 27.7 ms in 273 men and 421.1 ± 21.5 ms in 441 children (individuals younger than 14 years). Abnormal QTc was found in 13 (4.1%) women, 20 (7.3%) men, and 72 (16.3%) children. In the studied group, no recessive mutation of KNCQ1 or KCNE1 was found. In 6 patients, other mutations were found: in KCNQ1 (n = 1), in KCNH2 (n = 3) and in SCN5A (n = 1), which were pathogenic for long-QT-syndromes (LQTS), and 2 mutations of unknown clinical significance in SCN5A. Overall, out of these 6 patients LQTS was diagnosed in 3 asymptomatic patients, but with abnormal QTc and in 2 patients with normal QTc, but who were previously treated for epilepsy. CONCLUSIONS: Jervell and Lange-Nielsen syndrome is a very rare condition even in a population with hearing loss. In this population, the prevalence of prolonged QT interval is increased over the general population. Further investigations are necessary.

[Calreticulin, Ca2+-binding chaperon of the endoplasmic reticulum]. / Kalretikulina, bialko opiekuncze regulujace stezenie Ca2+ w siateczce sródplazmatycznej.

The endoplasmic reticulum (ER) plays a vital role in many cellular processes, including Ca2+ storage and release. Calreticulin is a Ca2+-binding chaperon residing in ER. The protein is a key component of the quality control pathways in ER. In the ER lumen, calreticulin performs two major functions, works as a chaperon and regulates Ca2+ homeostasis. In cardiac muscle, calreticulin plays an important role in cardiac development and pathology.

A novel life-threatening mutation in long QT2 syndrome.

BACKGROUND AND AIM: The aim of the report was to present a novel mutation in KCNH2 in a family with life-threatening long QT syndrome. METHODS: A genetic study using the method of next generation sequencing was performed in a 47-year-old woman after several episodes of syncope and torsade de pointes after sudden stress, with familial history of sudden death in first-degree female relatives. The study was performed also in her three asymptomatic children. Prolongation of QTc and typical ECG pattern of long QT2 were seen in the index case and in her youngest son. RESULTS: Novel mutations (p.F617V) in exon 7 of KCNH2 were found in the index case and in her youngest son. CONCLUSIONS: A novel heterozygous missense mutation in exon 7 of KCNH2 gene, causing a protein change p.F617V, was found in a family with life-threatening arrhythmias in women and clinical outcome typical for long QT2 syndrome.