MET is a new confirmed gene responsible for familial distal arthrogryposis

In this Correspondence, F. Mari and colleagues report a second two-generation family with distal arthrogryposis caused by a mutation in MET tyrosine kinase.

Liver Involvement in Patients with Rare MBOAT7 Variants and Intellectual Disability: A Case Report and Literature Review

The membrane-bound O-acyltransferase domain-containing 7 (MBOAT7) protein is an acyltransferase catalyzing arachidonic acid incorporation into lysophosphatidylinositol. Patients with rare, biallelic loss-of-function variants of the MBOAT7 gene display intellectual disability with neurodevelopmental defects. The rs641738 inherited variant associated with reduced hepatic MBOAT7 expression has been linked to steatotic liver disease susceptibility. However, the impact of biallelic loss-of-function MBOAT7 variants on liver disease is not known. We report on a 2-year-old girl with MBOAT7-related intellectual disability and steatotic liver disease, confirming that MBOAT7 loss-of-function predisposes to liver disease.

Clinical features and magnesium levels: Novel insights in 15q11.2 BP1-BP2 copy number variants

BACKGROUND

Investigating copy number variations (CNVs) such as microdeletions or microduplications can significantly contribute to discover the aetiology of neurodevelopmental disorders. 15q11.2 genomic region, including NIPA1 and NIPA2 genes, contains a recurrent but rare CNV, flanked by the break points BP1 and BP2. Both BP1-BP2 microdeletion and microduplication have been associated with intellectual disability (ID), neuropsychiatric/behavioural disturbances and mild clinical features, even if with incomplete penetrance and variable expressivity. The pathogenic role of this CNV is quite unclear though. Unknown variants in other DNA regions and parent-of-origin effect (POE) are some of the mechanisms that have been proposed as an explanation of the wide phenotypic variability. As NIPA1 and NIPA2 encode for proteins that mediate magnesium (Mg²⁺ ) metabolism, it has been suggested that urinary Mg²⁺ levels could potentially represent informative and affordable biomarkers for a rapid screening of 15q11.2 duplications or deletions. Furthermore, magnesium supplementation has been proposed as possible therapeutic strategy.

METHODS

Thirty one children with ID and/or other neurodevelopmental disorders carrying either a duplication or a deletion in 15q11.2 BP1-BP2 region have been recruited. When available, blood samples from parents have been analysed to identify the CNV origin. All participants underwent family and medical data collection, physical examination and neuropsychiatric assessment. Electroencephalogram (EEG) and brain magnetic resonance imaging (MRI) scan were performed in 15 children. In addition, 11 families agreed to participate to the assessment of blood and urinary Mg²⁺ levels.

RESULTS

We observed a highly variable phenotypic spectrum of developmental issues encompassing ID in most subjects as well as a variety of behavioural disorders such as autism and attention-deficit disorder/attention-deficit hyperactivity disorder. Dysmorphic traits and malformations were detected only in a minority of the participants, and no clear association with growth anomalies was found. Abnormal brain MRI and/or EEG were reported respectively in 64% and 92% of the subjects. Inheritance assessment highlighted an excess of duplication of maternal origin, while cardiac alterations were detected only in children with 15q11.2 CNV inherited from the father. We found great variability in Mg²⁺ urinary values, without correlation with 15q11.2 copy numbers. However, the variance of urinary Mg²⁺ levels largely increases in individuals with 15q11.2 deletion/duplication.

CONCLUSIONS

This study provides further evidence that 15q11.2 BP1-BP2 CNV is associated with a broad spectrum of neurodevelopmental disorders and POE might be an explanation for clinical variability. However, some issues may question the real impact of 15q11.2 CNV on the phenotype in the carriers: DNA sequencing could be useful to exclude other pathogenic gene mutations. Our results do not support the possibility that urinary Mg²⁺ levels can be used as biomarkers to screen children with neurodevelopmental disorders for 15q11.2 duplication/deletion. However, there are evidences of correlations between 15q11.2 BP1-BP2 CNV and Mg²⁺ metabolism and future studies may pave the way to new therapeutic options.

Non-invasive evaluation of pulmonary capillary wedge pressure using the left atrial expansion index in mitral valve stenosis, prosthesis and repair

Pulmonary capillary wedge pressure (PCWP) non-invasive evaluation is limited in patients with mitral valve (MV) stenosis, prosthesis, and surgical repair. This study aimed to assess the left atrial expansion index (LAEI) measured through transthoracic echocardiography (TTE) as a novel parameter for estimating PCWP in these challenging cardiac conditions. We performed a retrospective, cross-sectional study, including chronic cardiac patients receiving within 24 h a clinically indicated right heart catheterization (RHC) and transthoracic echocardiographic (TTE) exam. PCWP measured during RHC was used as the reference. TTE measurements were performed offline, blinded to RHC results. LAEI was calculated as LAEI = [(LAmaxVolume-LAminVolume)/LAminVolume] × 100. We included 167 patients (age = 73 ± 11.5 years; PCWP = 18 ± 7.7 mmHg) with rheumatic mitral valve (MV) stenosis (16.2%), degenerative MV stenosis (51.2%), MV prosthesis (18.0%), and MV surgical repair (13.8%). LAEI correlated logarithmically with PCWP, and the log-transformed LAEI (lnLAEI) showed a good linear association with PCWP (r = - 0.616; p < 0.001). lnLAEI was an independent PCWP determinant, providing added predictive value over conventional clinical (age, atrial fibrillation, heart rate, MV subgroups) and echocardiographic variables (LVEF, MV effective orifice area, MV mean gradient, net atrioventricular compliance, and pulmonary arterial systolic pressure). lnLAEI identified PCWP > 12 mmHg with AUC = 0.870, p < 0.001; and PCWP > 15 mmHg with AUC = 0.797, p < 0.001, with an optimal cut-off of lnLAEI < 3.69. The derived equation PCWP = 36.8-5.5xlnLAEI estimated the invasively measured PCWP ± 6.1 mmHg. In this cohort of patients with MV stenosis, prosthesis, and surgical repair, lnLAEI resulted in a helpful echocardiographic parameter for PCWP estimation.

Development and Implementation of the AIDA International Registry for Patients With VEXAS Syndrome

Objective

The aim of this paper is to present the AutoInflammatory Disease Alliance (AIDA) international Registry dedicated to Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic (VEXAS) syndrome, describing its design, construction, and modalities of dissemination.

Methods

This Registry is a clinical, physician-driven, population- and electronic-based instrument designed for the retrospective and prospective collection of real-life data. Data gathering is based on the Research Electronic Data Capture (REDCap) tool and is intended to obtain real-world evidence for daily patients' management. The Registry may potentially communicate with other on-line tools dedicated to VEXAS syndrome, thus enhancing international collaboration and data sharing for research purposes. The Registry is practical enough to be easily modified to meet future needs regarding VEXAS syndrome.

Results

To date (April 22^nd, 2022), 113 Centers from 23 Countries in 4 continents have been involved; 324 users (114 Principal Investigators, 205 Site Investigators, 2 Lead Investigators, and 3 data managers) are currently able to access the registry for data entry (or data sharing) and collection. The Registry includes 4,952 fields organized into 18 instruments designed to fully describe patient's details about demographics, clinical manifestations, symptoms, histologic details about skin and bone marrow biopsies and aspirate, laboratory features, complications, comorbidities, therapies, and healthcare access.

Conclusion

This international Registry for patients with VEXAS syndrome will allow the achievement of a comprehensive knowledge about this new disease, with the final goal to obtain real-world evidence for daily clinical practice, especially in relation to the comprehension of this disease about the natural history and the possible therapeutic approaches. This Project can be found on https://clinicaltrials.gov NCT05200715.

Prognostic Significance of Feature-Tracking Right Ventricular Global Longitudinal Strain in Non-ischemic Dilated Cardiomyopathy

Aims: Left ventricular global longitudinal strain (GLS) by cardiac magnetic resonance feature tracking (CMR-FT) analysis has shown an incremental prognostic value compared to classical parameters in non-ischemic dilated cardiomyopathy (NICM). However, less is known about the role of right ventricular (RV) GLS. Our objective was to evaluate the prognostic impact of RV-GLS by CMR-FT analysis in a population of NICM patients.

Methods: In this multicenter study, we examined NICM patients evaluated with a comprehensive CMR-FT study. Major cardiac events (MACEs) were considered as the study primary outcome measure and were defined as a composite of (a) cardiovascular death, (b) cardiac transplant or destination therapy ventricular assist device, (c) hospitalization for life-threatening ventricular arrhythmias or implantable cardiac defibrillator appropriate intervention. Heart failure (HF) related events, including hospitalizations and life-threatening arrhythmia-related events were considered as secondary end-points. Receiver operating time-dependent analysis were used to calculate the possible additional effect of RV-GLS to standard evaluation.

Results: We consecutively enrolled 273 patients. During a median follow-up of 39 months, 41 patients (15%) experienced MACEs. RV-GLS and LV late gadolinium emerged as the strongest prognostic CMR-FT variables: their association provided an estimated 3-year MACEs rate of 29%. The addition of RV-GLS significantly improved the prognostic accuracy in predicting MACEs with respect to the standard evaluation including LGE (areas under the curve from 0.71 [0.66–0.82] to 0.76 [0.66–0.86], p = 0.03). On competing risk analysis, RV-GLS showed a significant ability to reclassify overall both HF-related and life-threatening arrhythmia-related events, regardless of LV and RV ejection fraction.

Conclusions: In NICM patients, RV-GLS showed a significant prognostic role in reclassifying the risk of MACEs, incremental with respect to standard evaluation with standard prognostic parameters.

New Candidates for Autism/Intellectual Disability Identified by Whole-Exome Sequencing

Intellectual disability (ID) is characterized by impairments in the cognitive processes and in the tasks of daily life. It encompasses a clinically and genetically heterogeneous group of neurodevelopmental disorders often associated with autism spectrum disorder (ASD). Social and communication abilities are strongly compromised in ASD. The prevalence of ID/ASD is 1–3%, and approximately 30% of the patients remain without a molecular diagnosis. Considering the extreme genetic locus heterogeneity, next-generation sequencing approaches have provided powerful tools for candidate gene identification. Molecular diagnosis is crucial to improve outcome, prevent complications, and hopefully start a therapeutic approach. Here, we performed parent–offspring trio whole-exome sequencing (WES) in a cohort of 60 mostly syndromic ID/ASD patients and we detected 8 pathogenic variants in genes already known to be associated with ID/ASD (SYNGAP1, SMAD6, PACS1, SHANK3, KMT2A, KCNQ2, ACTB, and POGZ). We found four de novo disruptive variants of four novel candidate ASD/ID genes: MBP, PCDHA1, PCDH15, PDPR. We additionally selected via bioinformatic tools many variants in unknown genes that alone or in combination can contribute to the phenotype. In conclusion, our data confirm the efficacy of WES in detecting pathogenic variants of known and novel ID/ASD genes.

Left Atrial Expansion Index for Noninvasive Estimation of Pulmonary Capillary Wedge Pressure: A Cardiac Catheterization Validation Study

BACKGROUND

Pulmonary capillary wedge pressure (PCWP) plays a pivotal role in cardiac disease diagnosis and management. Right heart catheterization (RHC) invasively provides accurate PCWP measurement, but it is impractical for widespread use in all patients. The left atrial expansion index (LAEI), measured on transthoracic echocardiography, describes the relative left atrial volume increase during the left atrial reservoir phase. The aim of this study was to validate LAEI as a noninvasive parameter for PCWP estimation.

METHODS

A total of 649 chronic cardiac patients (mean age, 66 ± 14 years; mean PCWP, 14 ± 7.6 mm Hg; mean left ventricular ejection fraction, 50 ± 15%) who underwent both clinically indicated RHC and transthoracic echocardiography within 24 hours were retrospectively enrolled. Patients were randomly divided into derivation (n = 509) and validation (n = 140) cohorts. PCWP was measured during RHC and defined as elevated when >12 mm Hg. Transthoracic echocardiographic parameters and LAEI were measured offline, blinded to RHC results.

RESULTS

In the derivation cohort, LAEI correlated logarithmically with PCWP, and the log-transformed LAEI (lnLAEI) correlated linearly with PCWP (r = -0.73, P < .001). lnLAEI showed an independent and additive predictive role for PCWP estimation over clinical and diastolic dysfunction (DD) parameters. The diagnostic accuracy of lnLAEI for elevated PCWP identification (area under the curve = 0.875, P < .001; optimal lnLAEI cutoff < 4.02) was higher than either the single DD parameters or their combination. In the validation cohort, lnLAEI cutoff < 4.02 showed higher accuracy than the 2016 DD algorithm (88% vs 74%) for elevated PCWP identification. Finally, the equation PCWP = 38.3 - 6.2 × lnLAEI, obtained from the derivation cohort, predicted invasively measured PCWP in the validation cohort.

CONCLUSIONS

In a cohort of patients with various chronic cardiac diseases, lnLAEI performed better than DD parameters and the 2016 DD algorithm for PCWP estimation. lnLAEI might be a useful echocardiographic parameter for noninvasive PCWP estimation.

Added value of left atrial expansion index for non-invasive estimation of pulmonary capillary wedge pressure

Introduction

Right heart catheterization (RHC) is the reference technique for pulmonary capillary wedge pressure (PCWP) measurement but remains invasive. Transthoracic echocardiography (TTE) diastolic parameters (DPs) are used as non-invasive surrogates but have suboptimal accuracy. Left atrial expansion index (LAEI), describing LA reservoir function, could be used for indirectly estimate PCWP.

Purpose

To evaluate the correlation between LAEI and PCWP and to compare LAEI accuracy against DPs in estimating PCWP.

Methods

We retrospectively included the patients admitted to our department from 05/2015 to 02/2018 who underwent both a clinically indicated RHC and TTE within 24 hours. PCWP was obtained during RHC. DPs were measured offline and LAEI was calculated from LA maximum volume (MaxVol) and LA minimum volume (MinVol) as LAEI = [(LAMaxVol − LAMinVol) / LAMinVol)] × 100.

Results

We enrolled 405 patients (left ventricular ejection fraction (LVEF)&lt;50% n=172; PCWP&gt;12mmHg n=209). LAEI showed a logarithmic correlation with PCWP. The log-transformed LAEI (lnLAEI) had an excellent linear correlation (r=−0.82; p&lt;0.001) with PCWP, higher than DPs (LAMaxVoli: r=0.42; E/A: r=0.57; E/e': r=0.51; TRMaxVel r=0.17; all p&lt;0.001). lnLAEI had the highest accuracy in identifying PCWP&gt;12 mmHg (lnLAEI AUC 0.921, p&lt;0.001) when compared to DPs and their association (Figure). lnLAEI showed an independent and added predictive value in estimating PCWP in a model including atrial fibrillation (Afib), heart rate (HR), LVEF, mitral regurgitation (MR), LAMaxVoli, E/A, E/e' and TRMaxVel (Table).

Conclusions

LAEI is a simple parameter strongly associated with PCWP which might be used for PCWP estimation.

Funding Acknowledgement

Type of funding source: None

P173 When the heart doesn"t want to grow up

Background

Blood cysts of heart valves are uncommon and, usually, incidental findings in pediatric population. Rarely seen in adults, blood cysts are normally asymptomatic, even though several cases of embolization, valvular disfunction and left ventricle outflow tract (LVOT) obstruction have been described. Clinical Presentation. We report the case of a 23 year-old woman, with history of a small nodular mass of the mitral valve, found on a previous cardiac magnetic resonance (CMR) at the age of thirteen, who was admitted to our emergency department complaining atypical chest pain. She denied shortness of breath, syncope, tachycardia and fever. She was hemodynamically stable and a fast regression of symptoms was observed. The physical examination was unremarkable. Both the electrocardiogram (ECG) and blood tests were normal. A chest radiography showed normal heart size, without other abnormalities. After having ruled out an acute coronary syndrome, the patient was discharged with the indication to undergo further cardiological assessments. Diagnostic techniques and their most important findings. Therefore, a trans-thoracic echocardiogram was performed revealing normal biventricular function, no aortic root dilation, no pericardial effusion, no valvular regurgitation or stenosis. A round (7x11 mm) mass with hyperechogenic borders and hypoechogenic content was detected on the ventricular side of the anterior mitral valve leaflet consistent with a valvular blood cyst (figure 1: a,b,c). Only trivial mitral valve regurgitation without LVOT obstruction was present. The 3D echo reconstruction allowed to confirm the suspicion of blood cyst and detect a cleft of the posterior mitral valve leaflet, located in the P2 scallop (figure 1: d,e). A repeated CMR showed no contrast enhancement of the mass. Due to the clinical stability and the absence of complications, the patient was suggested to continue an echocardiographic follow-up. Discussion. Cardiac blood cysts are a rare condition with uncertain origin, usually found in infants in the first six months of life. A natural regression after that age has been described, making this condition very unusual in adults. Despite its benign features, when persistent beyond the childhood, the blood cyst can grow and reach even huge dimensions, potentially impairing the valvular function and/or causing LVOT obstruction. Another potential complication of blood cysts may be the arterial embolization. In all these situations surgical resection must be considered. In our patient, the contribution of trans-thoracic echocardiogram and in particular the 3D reconstruction, were pivotal to address the correct diagnosis.

Abstract P173 Figure 1

Development and Validation of a Distal Embolization Risk Score During Primary Angioplasty in ST-Elevation Myocardial Infarction

This study aims to develop and validate a new angiographic risk score to predict the risk of distal embolization (DE) during primary percutaneous coronary intervention (p-PCI) for ST-elevation myocardial infarction. Study included data from 1,200 patients who underwent p-PCI. The cohort was randomly split into a derivation cohort (n = 814) and a validation cohort (n = 386). Logistic regression was used to examine the relation between risk factors and the occurrence of DE. To each covariate in the model was assigned an integer score based on the regression coefficients. Variables included in the risk score, according to multivariable analysis, were occlusion pattern of infarct-related artery, Thrombolysis In Myocardial Infarction Thrombus Score 2 to 4, reference vessel diameter ≥3.5 mm, and lesion length >20 mm. To each variable was assigned a 0- to +2-point score according to the strength of the statistical association. Rates of DE in low-, intermediate-, and high-risk groups were 5.6%, 15.8%, and 40% in the derivation cohort (p for trend <0.0001; C-statistic 0.70) and 7.5%, 12.1%, and 37.9% in the validation cohort (p for trend <0.0001; C-statistic 0.62), respectively. In conclusion, the individual risk of DE in patients who underwent p-PCI can be predicted using a simple 4-variables model based on angiographic features.