Biallelic variants in TOR1AIP1, encoding the integral nuclear membrane protein LAP1 (lamina-associated polypeptide 1) with two functional isoforms LAP1B and LAP1C, have initially been linked to muscular dystrophies with variable cardiac and neurological impairment. Furthermore, a recurrent homozygous nonsense alteration, resulting in loss of both LAP1 isoforms, was identified in seven likely related individuals affected by multisystem anomalies with progeroid-like appearance and lethality within the 1st decade of life. Here, we have identified compound heterozygosity in TOR1AIP1 affecting both LAP1 isoforms in two unrelated individuals affected by congenital bilateral hearing loss, ventricular septal defect, bilateral cataracts, mild to moderate developmental delay, microcephaly, mandibular hypoplasia, short stature, progressive muscular atrophy, joint contractures and severe chronic heart failure, with much longer survival. Cellular characterization of primary fibroblasts of one affected individual revealed absence of both LAP1B and LAP1C, constitutively low lamin A/C levels, aberrant nuclear morphology including nuclear cytoplasmic channels, and premature senescence, comparable to findings in other progeroid forms of nuclear envelopathies. We additionally observed an abnormal activation of the extracellular signal-regulated kinase 1/2 (ERK 1/2). Ectopic expression of wild-type TOR1AIP1 mitigated these cellular phenotypes, providing further evidence for the causal role of identified genetic variants. Altogether, we thus further expand the TOR1AIP1associated phenotype by identifying individuals with biallelic loss-of-function variants who survived beyond the 1st decade of life and reveal novel molecular consequences underlying the TOR1AIP1-associated disorders.

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Background: Several cardiovascular biomarkers have regulatory functions in perinatal physiology. Aim: This study aimed to analyze the feto-maternal distribution pattern of biomarkers in samples of amniotic fluid, umbilical arterial blood, umbilical venous blood, and maternal blood samples, and to establish reference values. Each linked sample set consisted of the combined samples obtained in an individual pregnancy. Study design: We performed a prospective, observational, cross-sectional, single-center study. Subjects: The sample cohort included 189 neonates who were born to 170 mothers. A total of 162/189 neonates were full term and 129/189 were delivered by elective cesarean section. Outcome measures: Midregional pro-adrenomedullin (MRproADM [nmol/L]), midregional pro-atrial natriuretic peptide (MRproANP [pmol/L]), brain natriuretic peptide (BNP [pg/mL]), N-terminal pro-brain natriuretic peptide (NTproBNP [pg/mL]), copeptin [pmol/L], and high-sensitive troponin I (hsTnI [pg/mL]) levels were measured. Results: In singleton, full-term, primary cesarean deliveries ( n = 91), biomarker levels (median, [IQR]) at delivery were as follows. MRproADM levels in umbilical arterial blood/umbilical venous blood/amniotic fluid/maternal blood were 0.88 (0.20)/0.95 (0.18)/2.80 (1.18)/1.10 (0.54), respectively. MRproANP levels were 214.23 (91.38)/216.03 (86.15)/0.00 (3.82)/50.67 (26.81), respectively. BNP levels were 14.60 (25.18)/22.08 (18.91)/7.15 (6.01)/6.20 (18.23), respectively. NTproBNP levels were 765.48 (555.24)/816.45 (675.71)/72.03 (55.58)/44.40 (43.94), respectively. Copeptin levels were 46.17 (290.42)/5.54 (9.08)/9.97 (7.44)/4.61 (4.59), respectively. Levels of hsTnI were 6.20 (4.25)/5.60 (5.01)/0.45 (1.73)/2.50 (2.40), respectively. Conclusion: We determined reference values for biomarkers in term neonates delivered by primary cesarean section in amniotic fluid, umbilical arterial and venous blood, and maternal blood. Biomarkers in the fetal circulation appear to be of primary fetal origin, except for MRproADM.

The major spliceosome mediates pre-mRNA splicing by recognizing the highly conserved sequences at the 5’ and 3’ splice sites and the branch point. More than 150 proteins participate in the splicing process and are organized in the spliceosomal A, B, and C complexes. FRA10AC1 is a peripheral protein of the spliceosomal C complex and its ortholog in the green alga facilitates recognition or interaction with splice sites. We identified biallelic pathogenic variants in FRA10AC1 in five individuals from three consanguineous families. The two unrelated patients 1 and 2 with loss-of-function variants showed developmental delay, intellectual disability, and no speech, while three siblings with the c.494_496delAAG (p.Glu165del) variant had borderline to mild intellectual disability. All patients had microcephaly, hypoplasia or agenesis of the corpus callosum, growth retardation, and craniofacial dysmorphism. FRA10AC1 transcripts and proteins were drastically reduced or absent in fibroblasts of patients 1 and 2. In a heterologous expression system, the p. Glu165del variant impacts intrinsic stability of FRA10AC1 but does not affect its nuclear localization. By co-immunoprecipitation, we found ectopically expressed HA-FRA10AC1 in complex with endogenous DGCR14, another component of the spliceosomal C complex, while the splice factors CHERP, NKAP, RED, and SF3B2 could not be co-immunoprecipitated. Using an in vitro splicing reporter assay, we did not obtain evidence for FRA10AC1 deficiency to suppress missplicing events caused by mutations in the highly conserved dinucleotides of 5’ and 3’ splice sites in an in vitro splicing assay in patient-derived fibroblasts. Our data highlight the importance of specific peripheral spliceosomal C complex proteins for neurodevelopment. It remains possible that FRA10AC1 may have other and/or additional cellular functions, such as coupling of transcription and splicing reactions.

The long-term outcome of patients with single ventricles improved over time, but remains poor compared to other congenital heart lesions with biventricular circulation. Main cause for this unfavourable outcome is the unphysiological hemodynamic of the Fontan circulation, such as subnormal systemic cardiac output and increased systemic-venous pressure. To overcome this limitation, we are developing the concept of a contractile extracardiac Fontan-tunnel. In this study, we evaluated the survival and structural development of a tissue-engineered conduit under in vivo conditions. Engineered heart tissue was generated from ventricular heart cells of neonatal Wistar rats, fibrinogen and thrombin. Engineered heart tissues started beating around day 8 in vitro and remained contractile in vivo throughout the experiment. After culture for 14 days constructs were implanted around the right superior vena cava of Wistar rats (n = 12). Animals were euthanized after 7, 14, 28 and 56 days postoperatively. Hematoxylin and eosin staining showed cardiomyocytes arranged in thick bundles within the engineered heart tissue-conduit. Immunostaining of sarcomeric actin, alpha-actin and connexin 43 revealed a well -developed cardiac myocyte structure. Magnetic resonance imaging (d14, n = 3) revealed no constriction or stenosis of the superior vena cava by the constructs. Engineered heart tissues survive and contract for extended periods after implantation around the superior vena cava of rats. Generation of larger constructs is warranted to evaluate functional benefits of a contractile Fontan-conduit.

Introduction. Anemia is prevalent in adult heart failure patients and appears to be an independent risk factor for morbidity and mortality. The purpose of this work is to determine the prevalence of anemia in children with heart failure from dilated cardiomyopathy (DCM) and to evaluate its influence on morbidity and mortality. Methods. A homogenous group of 58 children with congestive heart failure from DCM was evaluated for heart failure symptoms, appearance of anemia, hospitalization, age of first clinical appearance, necessity of transfusion, and death during medical attendance. Anemic and nonanemic patients were analyzed for differences in age distribution, morbidity, and mortality. Results. Anemia was present in 64% of DCM patients. Hospitalization secondary to heart failure was significantly elevated in heart failure patients with anemia (mean 35.1 ± 40.5 versus 9.97 ± 9.65 days per year, P < 0.05). However, mortality was not elevated. Significant relations of age and prevalence of anemia or age and severity of anemia did not appear. Conclusion. Anemia is prevalent in pediatric patients with congestive heart failure from DCM and appears in all age classes. Hospitalization as a surrogate of morbidity is elevated in heart failure patients developing anemia, but mortality risk did not increase.

Almost 2 years into the pandemic and with vaccination of children significantly lagging behind adults, long-term pediatric humoral immune responses to SARS-CoV-2 are understudied. The C19.CHILD Hamburg (COVID-19 Child Health Investigation of Latent Disease) Study is a prospective cohort study designed to identify and follow up children and their household contacts infected in the early 2020 first wave of SARS-CoV-2. We screened 6113 children < 18 years by nasopharyngeal swab-PCR in a low-incidence setting after general lockdown, from May 11 to June 30, 2020. A total of 4657 participants underwent antibody testing. Positive tests were followed up by repeated PCR and serological testing of all household contacts over 6 months. In total, the study identified 67 seropositive children (1.44%); the median time after infection at first presentation was 83 days post-symptom onset (PSO). Follow-up of household contacts showed less than 100% seroprevalence in most families, with higher seroprevalence in families with adult index cases compared to pediatric index cases (OR 1.79, P = 0.047). Most importantly, children showed sustained seroconversion up to 9 months PSO, and serum antibody concentrations persistently surpassed adult levels (ratio serum IgG spike children vs. adults 90 days PSO 1.75, P < 0.001; 180 days 1.38, P = 0.01; 270 days 1.54, P = 0.001). In a low-incidence setting, SARS-CoV-2 infection and humoral immune response present distinct patterns in children including higher antibody levels, and lower seroprevalence in families with pediatric index cases. Children show long-term SARS-CoV-2 antibody responses. These findings are relevant to novel variants with increased disease burden in children, as well as for the planning of age-appropriate vaccination strategies.

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