Savina Mannarino

Prevalence of the Congenital Long-QT Syndrome

Background— The prevalence of genetic arrhythmogenic diseases is unknown. For the long-QT syndrome (LQTS), figures ranging from 1:20 000 to 1:5000 were published, but none was based on actual data. Our objective was to define the prevalence of LQTS. Methods and Results— In 18 maternity hospitals, an ECG was performed in 44 596 infants 15 to 25 days old (43 080 whites). In infants with a corrected QT interval (QTc) >450 ms, the ECG was repeated within 1 to 2 weeks. Genetic analysis, by screening 7 LQTS genes, was performed in 28 of 31 (90%) and in 14 of 28 infants (50%) with, respectively, a QTc >470 ms or between 461 and 470 ms. A QTc of 451 to 460, 461 to 470, and >470 ms was observed in 177 (0.41%), 28 (0.06%), and 31 infants (0.07%). Among genotyped infants, disease-causing mutations were found in 12 of 28 (43%) with a QTc >470 ms and in 4 of 14 (29%) with a QTc of 461 to 470 ms. One genotype-negative infant (QTc 482 ms) was diagnosed as affected by LQTS on clinical grounds. Among family members of genotype-positive infants, 51% were found to carry disease-causing mutations. In total, 17 of 43 080 white infants were affected by LQTS, demonstrating a prevalence of at least 1:2534 apparently healthy live births (95% confidence interval, 1:1583 to 1:4350). Conclusions— This study provides the first data-based estimate of the prevalence of LQTS among whites. On the basis of the nongenotyped infants with QTc between 451 and 470 ms, we advance the hypothesis that this prevalence might be close to 1:2000. ECG-guided molecular screening can identify most infants affected by LQTS and unmask affected relatives, thus allowing effective preventive measures.

Long-Term Outcome and Risk Stratification in Dilated Cardiolaminopathies

OBJECTIVES The aim of this study was to analyze the long-term follow-up of dilated cardiolaminopathies. BACKGROUND Lamin A/C (LMNA) gene mutations cause a variety of phenotypes. In the cardiology setting, patients diagnosed with idiopathic dilated cardiomyopathy (DCM) plus atrioventricular block (AVB) constitute the majority of reported cases. METHODS Longitudinal retrospective observational studies were conducted with 27 consecutive families in which LMNA gene defects were identified in the probands, all sharing the DCM phenotype. RESULTS Of the 164 family members, 94 had LMNA gene mutations. Sixty of 94 (64%) were phenotypically affected whereas 34 were only genotypically affected, including 5 with pre-clinical signs. Of the 60 patients, 40 had DCM with AVB, 12 had DCM with ventricular tachycardia/fibrillation, 6 had DCM with AVB and Emery-Dreifuss muscular dystrophy type 2 (EDMD2), and 2 had AVB plus EDMD2. During a median of 57 months (interquartile range 36 to 107 months), we observed 49 events in 43 DCM patients (6 had a later event, excluded from the analysis). The events were related to heart failure (15 heart transplants, 1 death from end-stage heart failure) and ventricular arrhythmias (15 sudden cardiac deaths and 12 appropriate implantable cardioverter-defibrillator interventions). By multivariable analysis, New York Heart Association functional class III to IV and highly dynamic competitive sports for >or=10 years were independent predictors of total events. By a bivariable Cox model, splice site mutations and competitive sport predicted sudden cardiac death. CONCLUSIONS Dilated cardiomyopathies caused by LMNA gene defects are highly penetrant, adult onset, malignant diseases characterized by a high rate of heart failure and life-threatening arrhythmias, predicted by New York Heart Association functional class, competitive sport activity, and type of mutation.

Rationale and design of a trial evaluating the effects of losartan vs. nebivolol vs. the association of both on the progression of aortic root dilation in Marfan syndrome with FBN1 gene mutations.

Background The major clinical problem of Marfan syndrome (MFS) is the aortic root aneurysm, with risk of dissection when the root diameter approximates 5 cm. In MFS, a key molecule, transforming growth factor-β (TGF-β), normally bound to the extracellular matrix, is free and activated. In an experimental setting, TGF-β blockade prevents the aortic root structural damage and dilatation. The angiotensin receptor 1 blockers (sartanics) exert an anti-TGF-β effect; trials are now ongoing for evaluating the effect of losartan compared with atenolol in MFS. β-Adrenergic blockers are the drugs most commonly used in MFS. The third-generation β-adrenergic blocker nebivolol retains the β-adrenergic blocker effects on heart rate and further exerts antistiffness effects, typically increased in MFS. Methods The open-label phase III study will include 291 patients with MFS and proven FBN1 gene mutations, with aortic root dilation (z-score ≥2.5). The patients will be randomized to nebivolol, losartan and the combination of the two drugs. The primary end point is the comparative evaluation of the effects of losartan, nebivolol and the association of both on the progression of aortic root growth rate. Secondary end points include the pharmacokinetics of the two drugs, comparative evaluation of serum levels of total and active TGF-β, quantitative assessment of the expression of the mutated gene (FBN1, both 5′ and 3′), pharmacogenetic bases of drug responsiveness. The quality of life evaluation in the three groups will be assessed. Statistical evaluation includes an interim analysis at month 24 and conclusive analyses at month 48. Conclusion The present study will add information about pharmacological therapy in MFS, supporting the new application of angiotensin receptor 1 blockers and finding β-adrenergic blockers that may give more specific effects. Moreover, the study will further deepen understanding of the pathogenetic mechanisms that are active in Marfan syndrome through the pharmacogenomic and transcriptomic mechanisms that may explain MFS phenotype variability.

The natural course and the impact of therapies of cardiac involvement in the mucopolysaccharidoses

OBJECTIVE To analyze cardiac involvement and its progression in mucopolysaccharidoses, and to assess the short term impact of new therapeutic strategies. PATIENTS AND METHODS We studied echocardiographically 57 patients with various types of mucopolysaccharidoses, specifically types I, II, III, IV and VI, with a median age at the diagnosis of cardiac involvement of 5 years, following them for a median of 4.6 years, with a range from 0.9 to 21.2 years. We used a scoring system, along with the so-called delta score, to quantify the severity of involvement at baseline and at last examination, and to chart their progression over time. RESULTS Cases with cardiac involvement increased from 59.6% to 87.3% at the last examination. The scores increased with age, and were significantly different according to the specific type of mucopolysaccharidosis. Involvement of the mitral valve was most common, often associated with an aortic valvar anomaly and/or left ventricular hypertrophy. Patients with the first and second types had more severe involvement than those with the third or fourth types. Patients undergoing transplantation of haematopoietic stem cells seem to stabilize after an initial worsening while, in contrast, we were unable to demonstrate an effect of enzyme replacement therapy on the progression of the cardiac disease, possibly because those receiving such treatment had a higher median age, more severe cardiac disease and shorter follow-up. CONCLUSIONS Cardiac involvement was present early in more than a half of the patients identified as having mucopolysaccharidosis, and generally progressed, being more frequent and severe in the first and second types of the disease. Longer follow-up is needed to demonstrate any significant improvement induced by new therapies.

Barth syndrome associated with compound hemizygosity and heterozygosity of the TAZ and LDB3 genes.

Barth syndrome is an X‐linked recessive disorder caused by the tafazzin (TAZ) gene mutations and includes dilated cardiomyopathy (DCM) with left ventricular non‐compaction, neutropenia, skeletal myopathy, abnormal mitochondria and 3‐methylglutaconic aciduria. Dilated cardiomyopathy with left ventricular non‐compaction transmitted as an autosomal dominant condition has also been associated with LIM domain‐binding 3 (LDB3) gene defects. We describe a family in which the 12‐year‐old proband had left ventricular non‐compaction and DCM. His mother had five miscarriages, two other sons who died in infancy, and a healthy son and daughter. The proband showed left ventricular non‐compaction–DCM, skeletal myopathy, recurrent oral aphthous ulcers and cyclic neutropenia. The DCM progressively improved with age; medical therapy was discontinued at 5 years of age. At present, left ventricular function is normal and arrhythmias are absent. Magnetic resonance imaging documented left ventricular non‐compaction. However, oral aphthous ulcers and cyclic neutropenia have recurred. In the proband we identified two novel mutations, one of maternal origin in the TAZ gene (p.[Glu202ValfsX15]) and one of paternal origin in the LDB3 gene (p.[Thr350Ile]). The mother, brother and father are healthy; although the latter two show prominent left ventricle trabeculation without dysfunction. Expression studies of TAZ and LDB3 genes were conducted in family members and controls. In the proband, brother and father, LDB3 expression was similar to control cases. TAZ and LDB3 expression progressively declined with age in control both blood and myocardial samples. However, an endomyocardial biopsy performed in the proband at 6 months of age, showed significantly lower TAZ and LDB3 expression than in age‐matched myocardial controls. We believe that the clinical, genetic and expression data support the hypothesis that tafazzins are essential during fetal and early post‐natal life.

Constitutive Store-Operated Ca2+ Entry Leads to Enhanced Nitric Oxide Production and Proliferation in Infantile Hemangioma-Derived Endothelial Colony-Forming Cells

Clonal endothelial progenitor cells (EPCs) have been implicated in the aberrant vascular growth that features infantile hemangioma (IH), the most common benign vascular tumor in childhood that may cause ulceration, bleeding, and/or permanent disfigurement. Endothelial colony-forming cells (ECFCs), truly endothelial EPCs endowed with clonal ability and capable of forming patent vessels in vivo, remodel their Ca(2+) toolkit in tumor-derived patients to acquire an adaptive advantage. Particularly, they upregulate the proangiogenic store-operated Ca(2+) entry (SOCE) pathway due to the overexpression of its underlying components, that is, stromal interaction molecule 1 (Stim1), Orai1, and transient receptor potential canonical 1 (TRPC1). The present work was undertaken to assess whether and how the Ca(2+) signalosome is altered in IH-ECFCs by employing Ca(2+) and nitric oxide (NO) imaging, real-time polymerase chain reaction, western blotting, and functional assays. IH-ECFCs display a lower intracellular Ca(2+) release in response to either pharmacological (i.e., cyclopiazonic acid) or physiological (i.e., ATP and vascular endothelial growth factor) stimulation. Conversely, Stim1, Orai1, and TRPC1 transcripts and proteins are normally expressed in these cells and mediate a constitutive SOCE, which is sensitive to BTP-2, La(3+), and Pyr6 and recharges the intracellular Ca(2+) pool. The resting SOCE in IH-ECFCs is also associated to an increase in their proliferation rate and the basal production of NO compared to normal cells. Likewise, the pharmacological blockade of SOCE and NO synthesis block IH-ECFC growth. Collectively, these data indicate that the constitutive SOCE activation enhances IH-ECFC proliferation by augmenting basal NO production and sheds novel light on the molecular mechanisms of IH.

Congenital vascular rings: A clinical challenge for the pediatrician

Vascular rings are congenital anomalies that lead to variable degrees of respiratory problems or feeding difficulties by forming a complete or partial ring compressing the trachea, the bronchi, and the esophagus. The clinical diagnosis of vascular rings is often challenging for the pediatrician because the clinical manifestations are heterogeneous and nonspecific. Symptoms can vary from wheezing, stridor, dyspnea, and/or dysphagia to life‐threatening conditions; however, they may not be present. The aim of this study is to review the recent literature on this subject and describe new developments in diagnostics and imaging. Pediatr Pulmonol. 2015; 50:511–524.

Noonan syndrome associated with both a new Jnk-activating familial SOS1 and a de novo RAF1 mutations.

Noonan syndrome is a genetic condition characterized by congenital heart defects, short stature, and characteristic facial features. Familial or de novo mutations in PTPN11, RAF1, SOS1, KRAS, and NRAS are responsible for 60–75% of the cases, thus, additional genes are expected to be involved in the pathogenesis. In addition, the genotype–phenotype correlation has been hindered by the highly variable expressivity of the disease. For all these reasons, expanding the genotyped and clinically evaluated case numbers will benefit the clinical community. A mutation analysis has been performed on RAF1, SOS1, and GRB2, in 24 patients previously found to be negative for PTPN11 and KRAS mutations. We identified four mutations in SOS1 and one in RAF1, while no GRB2 variants have been found. Interestingly, the RAF1 mutation was present in a patient also carrying a newly identified p.R497Q familial SOS1 mutation, segregating with a typical Noonan Syndrome SOS1 cutaneous phenotype. Functional analysis demonstrated that the R497Q SOS1 mutation leads to Jnk activation, but has no effect on the Ras effector Erk1. We propose that this variant might contribute to the onset of the peculiar ectodermal traits displayed by the propositus amidst the more classical Noonan syndrome presentation. To our knowledge, this is the first reported case of a patient harboring mutations in two genes, with an involvement of both Ras and Rac1 pathways, indicating that SOS1 may have a role of modifier gene that might contribute the variable expressivity of the disease, evidencing a genotype–phenotype correlation in the family.

Correlation between cord blood, perinatal BNP values and echocardiographic parameters in healthy Italian newborns.

We evaluated the correlation between brain natriuretic peptide (BNP) in umbilical cord blood after normal pregnancy, in blood samples of twenty-nine Italian healthy newborns and paired echocardiographic parameters. Plasma BNP was evaluated in UCB (T0) and in blood on day 3 (T1), 30 (T2) of life. Echocardiographic parameters were recorded at T1 and T2. Median of BNP concentrations in cord blood was 8.6 pg/ml. Median BNP concentrations on T1 was 59.2 pg/ml, on T2 was 8.7 pg/ml. Significantly higher BNP concentrations were reported on T1 than T0 and T2 (p<0.0001), while no significant difference resulted between T0 and T2. Plasma BNP at T2 was significantly correlated with mVTI (p=0.006), E wave (p=0.004), LA (p=0.047), LVPW (p=0.004), M (p=0.025). No correlation was found with SF% and E/A. Our results confirm that in healthy and term neonates the cord blood BNP concentrations are low. On T1 BNP values are high with wide ranges because of physiological adjustment to postnatal circulation. When echocardiographic parameters are in normal ranges, BNP concentrations return to low levels on day 30. In healthy newborns left ventricular filling, LA size and M seem to influence BNP levels rather than left ventricular systolic and diastolic function.

Music benefits on postoperative distress and pain in pediatric day care surgery.

Postoperative effect of music listening has not been established in pediatric age. Response on postoperative distress and pain in pediatric day care surgery has been evaluated. Forty-two children were enrolled. Patients were randomly assigned to the music-group (music intervention during awakening period) or the non-music group (standard postoperative care). Slow and fast classical music and pauses were recorded and played via ambient speakers. Heart rate, blood pressure, oxygen saturation, glucose and cortisol levels, faces pain scale and Face, Legs, Activity, Cry, Consolability (FLACC) Pain Scale were considered as indicators of response to stress and pain experience. Music during awakening induced lower increase of systolic and diastolic blood pressure levels. The non-music group showed progressive increasing values of glycemia; in music-group the curve of glycemia presented a plateau pattern (P<0.001). Positive impact on reactions to pain was noted using the FLACC scale. Music improves cardiovascular parameters, stress-induced hyperglycemia. Amelioration on pain perception is more evident in older children. Positive effects seems to be achieved by the alternation of fast, slow rhythms and pauses even in pediatric age.