Description of the two dimensional layer-specific strain echocardiography phenotype of arrhythmogenic left ventricular cardiomyopathy.

BACKGROUND: Arrhythmogenic left ventricular cardiomyopathy (ALVC) is characterized by fibrofatty myocardial replacement evidenced on cardiac magnetic resonance (CMR) by late gadolinium enhancement (LGE) mainly involving subepicardium. The study aimed to describe the layer-specific strain (LSS) echocardiography phenotype of ALVC and to compare it to LGE features. METHODS: All consecutive ALVC pathogenic genetic variant carriers and non-carrier relatives were reparted in four pre-specified groups (overt ALVC (Group 1), isolated LGE (Group 2), pathogenic genetic variant carrier without ALVC phenotype (Group 3), no genetic variant carrier (Group 4)) and explored accordingly by CMR and LSS echocardiography. RESULTS: Eighty-five individuals were included. Endocardial global longitudinal strain (GLS) (GLSendo)-Epicardial GLS (GLSepi) gradient was predominantly altered in Group 1 illustrating transmural strain alteration in overt ALVC (3.8 ± 1.1 in Group 1, 4.3 ± 2.2 in Group 2, 5.2 ± 1.2 in Group 3, 5.4 ± 1.6 in Group 4, p=0.0017), whereas GLSepi was predominantly impaired in Group 2 (GLSendo, GLSepi = 15.0 ± 4.1%, 11.2 ± 3.3% respectively in Group 1, 20.5 ± 2.8%, 16.2 ± 5.5% in Group 2, 23.4 ± 3.3%, 18.2 ± 2.7% in Group 3, 24.6 ± 2.8%, 19.2 ± 1.9% in Group 4, all p<0.0001). GLSepi was able to detect subepicardial LGE in genetic variant carriers without overt ALVC with an area under curve (AUC) of 0.84 (0.73;0.95). However, segmental epicardial and endocardial strain behaved similarly and showed comparable diagnostic values for segmental LGE detection (AUC 0.72 (CI 0.69-0.76) and 0.73 (CI 0.70-0.76) respectively, p =0.4). CONCLUSION: LSS alteration in ALVC progresses from epicardium to endocardium along with disease severity. Irrespective of LSS analysis, that did not provide incremental diagnostic value for the detection and localization of LGE, strain echocardiography was shown to be a potential surrogate marker of LGE, including in apparently healthy individuals with isolated LV fibrosis.

Prevalence and phenotypes associated with ALPK3 null variants in a large French multicentric cohort: Confirming its involvement in hypertrophic cardiomyopathy.

Biallelic disease-causing variants in the ALPK3 gene were first identified in children presenting with a severe cardiomyopathy. More recently, it was shown that carriers of heterozygous ALPK3 null variants are at risk of developing hypertrophic cardiomyopathy (HCM) with an adult onset. Since the number of reported ALPK3 patients is small, the mutational spectrum and clinical data are not fully described. In this multi-centric study, we described the molecular and clinical spectrum of a large cohort of ALPK3 patients. Genetic testing using targeted next generation sequencing was performed in 16 183 cardiomyopathy index cases. Thirty-six patients carried at least one null ALPK3 variant. The five paediatric patients carried two ALPK3 variants, all presented an HCM phenotype with severe outcomes (one transplantation, one heart failure and one cardiac arrest). The 31 adult patients carried heterozygous variants and the main phenotype was HCM (n = 26/31); including 15% (n = 4) presented with an apical or a concentric form of hypertrophy. Reporting a large cohort of ALPK3 patients, this collaborative work confirmed a strong association with HCM and suggesting his screening in the context of idiopathic HCM.

Burden of rare variants in arrhythmogenic cardiomyopathy with right dominant form-associated genes provides new insights for molecular diagnosis and clinical management.

Arrhythmogenic cardiomyopathy with right dominant form (ACR) is a rare heritable cardiac cardiomyopathy disorder associated with sudden cardiac death. Pathogenic variants (PVs) in desmosomal genes have been causally related to ACR in 40% of cases. Other genes encoding nondesmosomal proteins have been described in ACR, but their contribution in this pathology is still debated. A panel of 71 genes associated with inherited cardiopathies was screened in an ACR population of 172 probands and 856 individuals from the general population. PVs and uncertain significance variants (VUS) have been identified in 36% and 18.6% of patients, respectively. Among the cardiopathy-associated genes, burden tests show a significant enrichment in PV and VUS only for desmosomal genes PKP2 (plakophilin-2), DSP (desmoplakin), DSC2 (desmocollin-2), and DSG2 (desmoglein-2). Importantly, VUS may account for 15% of ACR cases and should then be considered for molecular diagnosis. Among the other genes, no evidence of enrichment was detected, suggesting an extreme caution in the interpretation of these genetic variations without associated functional or segregation data. Genotype-phenotype correlation points to (1) a more severe and earlier onset of the disease in PV and VUS carriers, underlying the importance to carry out presymptomatic diagnosis in relatives and (2) to a more prevalent left ventricular dysfunction in DSP variant carriers.

Rapid diagnostic tests relying on antigen detection from stool as an efficient point of care testing strategy for giardiasis and cryptosporidiosis? Evaluation of a new immunochromatographic duplex assay.

Microscopy is the gold standard for the diagnosis of gastrointestinal parasites but is time-consuming and dependent on operator skills. Rapid diagnostic tests represent alternative methods but most evaluations have been conducted on a limited number of samples preventing their implementation in the clinical setting. We evaluated a new CE-IVD marked immunochromatographic assay (Crypto/Giardia K-SeT®, Coris Bioconcept) for the detection of G. intestinalis and Cryptosporidium spp. in 2 phases (retrospective and prospective) on a set of 482 stool samples including rare Cryptosporidium species. Besides G. intestinalis, this test could represent a rapid and reliable alternative to the modified Ziehl-Neelsen staining for the diagnosis of cryptosporidiosis (sensitivity/specificity were 89.2%/99.3% and 86.7%/100% for G. intestinalis and Cryptosporidium resp.), reducing diagnostic delays. Such strategy would also be time-saving by avoiding wet mount microscopy and concentrations steps, being particularly appropriate for laboratories having little expertise in microscopy or not able to implement molecular diagnostic methods.