Medulloblastoma in children with Fanconi anemia: Association with FA-D1/FA-N, SHH type and poor survival independent of treatment strategies.

BACKGROUND: Outcome of children with medulloblastoma (MB) and Fanconi Anemia (FA), an inherited DNA repair deficiency, has not been described systematically. Treatment is complicated by high vulnerability to treatment-associated side effects, yet structured data are lacking. This study aims at giving a comprehensive overview about clinical and molecular characteristics of pediatric FA MB patients. METHODS: Clinical data including detailed information on treatment and toxicities of six previously unreported FA MB patients were supplemented with data of 16 published cases. RESULTS: We identified 22 cases of children with FA and MB with clinical data available. All MBs with subgroup reporting were SHH-activated (n=9), confirmed by methylation profiling in five patients. FA MB patients exclusively belonged to complementation groups FA-D1 (n=16) or FA-N (n=3). Patients were treated with postoperative chemotherapy only (50%) or radiotherapy (RT)±chemotherapy (27%). 23% did not receive adjuvant therapy. Excessive treatment-related toxicities were frequent. Severe hematological toxicity occurred in 91% of patients treated with alkylating chemotherapy, while non-alkylating agents and RT were less toxic. Median overall survival (OS) was 1 year (95%CI 0.3-1.8). 1-year-progression-free-survival (PFS) was 26.3±10.1% and 1-year-OS was 42.1±11.3%. Adjuvant therapy prolonged survival (1y-OS/1y-PFS 0%/0% without adjuvant therapy vs. 53.3±12.9%/33.3±12.2% with adjuvant therapy, p=0.006/p=0.086). CONCLUSIONS: MB in FA patients is strongly associated with SHH activation and FA-D1/FA-N. Despite the dismal prognosis, adjuvant therapy may prolong survival. Non-alkylating chemotherapy and RT are feasible in selected patients with careful monitoring of toxicities and dose adjustments. Curative therapy for FA MB-SHH remains an unmet medical need.

Zebrafish as a model to investigate a biallelic gain-of-function variant in MSGN1, associated with a novel skeletal dysplasia syndrome.

BACKGROUND/OBJECTIVES: Rare genetic disorders causing specific congenital developmental abnormalities often manifest in single families. Investigation of disease-causing molecular features are most times lacking, although these investigations may open novel therapeutic options for patients. In this study, we aimed to identify the genetic cause in an Iranian patient with severe skeletal dysplasia and to model its molecular function in zebrafish embryos. RESULTS: The proband displays short stature and multiple skeletal abnormalities, including mesomelic dysplasia of the arms with complete humero-radio-ulna synostosis, arched clavicles, pelvic dysplasia, short and thin fibulae, proportionally short vertebrae, hyperlordosis and mild kyphosis. Exome sequencing of the patient revealed a novel homozygous c.374G > T, p.(Arg125Leu) missense variant in MSGN1 (NM_001105569). MSGN1, a basic-Helix-Loop-Helix transcription factor, plays a crucial role in formation of presomitic mesoderm progenitor cells/mesodermal stem cells during early developmental processes in vertebrates. Initial in vitro experiments show protein stability and correct intracellular localization of the novel variant in the nucleus and imply retained transcription factor function. To test the pathogenicity of the detected variant, we overexpressed wild-type and mutant msgn1 mRNA in zebrafish embryos and analyzed tbxta (T/brachyury/ntl). Overexpression of wild-type or mutant msgn1 mRNA significantly reduces tbxta expression in the tailbud compared to control embryos. Mutant msgn1 mRNA injected embryos depict a more severe effect, implying a gain-of-function mechanism. In vivo analysis on embryonic development was performed by clonal msgn1 overexpression in zebrafish embryos further demonstrated altered cell compartments in the presomitic mesoderm, notochord and pectoral fin buds. Detection of ectopic tbx6 and bmp2 expression in these embryos hint to affected downstream signals due to Msgn1 gain-of-function. CONCLUSION: In contrast to loss-of-function effects described in animal knockdown models, gain-of-function of MSGN1 explains the only mildly affected axial skeleton of the proband and rather normal vertebrae. In this context we observed notochord bending and potentially disruption of pectoral fin buds/upper extremity after overexpression of msgn1 in zebrafish embryos. The latter might result from Msgn1 function on mesenchymal stem cells or on chondrogenesis in these regions. In addition, we detected ectopic tbx6 and bmp2a expression after gain of Msgn1 function in zebrafish, which are interconnected to short stature, congenital scoliosis, limb shortening and prominent skeletal malformations in patients. Our findings highlight a rare, so far undescribed skeletal dysplasia syndrome associated with a gain-of-function mutation in MSGN1 and hint to its molecular downstream effectors.

Broadening the phenotypic and molecular spectrum of FINCA syndrome: Biallelic NHLRC2 variants in 15 novel individuals.

FINCA syndrome [MIM: 618278] is an autosomal recessive multisystem disorder characterized by fibrosis, neurodegeneration and cerebral angiomatosis. To date, 13 patients from nine families with biallelic NHLRC2 variants have been published. In all of them, the recurrent missense variant p.(Asp148Tyr) was detected on at least one allele. Common manifestations included lung or muscle fibrosis, respiratory distress, developmental delay, neuromuscular symptoms and seizures often followed by early death due to rapid disease progression.Here, we present 15 individuals from 12 families with an overlapping phenotype associated with nine novel NHLRC2 variants identified by exome analysis. All patients described here presented with moderate to severe global developmental delay and variable disease progression. Seizures, truncal hypotonia and movement disorders were frequently observed. Notably, we also present the first eight cases in which the recurrent p.(Asp148Tyr) variant was not detected in either homozygous or compound heterozygous state.We cloned and expressed all novel and most previously published non-truncating variants in HEK293-cells. From the results of these functional studies, we propose a potential genotype-phenotype correlation, with a greater reduction in protein expression being associated with a more severe phenotype.Taken together, our findings broaden the known phenotypic and molecular spectrum and emphasize that NHLRC2-related disease should be considered in patients presenting with intellectual disability, movement disorders, neuroregression and epilepsy with or without pulmonary involvement.

Hyper-IgE and Carcinoma in CADINS Disease.

Background: Atopic dermatitis (AD) affects up to 25% of children and 10% of adults in Western countries. When severe or recurrent infections and exceedingly elevated serum IgE levels occur in AD patients, an inborn error of immunity (IEI) may be suspected. The International Union of Immunological Societies classification lists variants in different genes responsible for so-called Hyper-IgE syndromes. Diagnosing an underlying IEI may influence treatment strategies. Methods: Clinical and diagnostic workup of family members are presented including a detailed immunological description and histology of the carcinoma. Functional testing of the novel variant in CARD11 underlying 'CARD11-associated atopy with dominant interference of NF-kB signaling' (CADINS) was performed. Results: We report on an 18-year-old patient with a long-standing history of infections, accompanied by hypogammaglobulinemia, intermittent agranulocytosis, atopy, eosinophilia and colitis. The working diagnosis of common variable immunodeficiency was revised when a novel heterozygous CARD11 variant [c.223C>T; p.(Arg75Trp)] was identified. Functional studies confirmed this variant to have a dominant negative (DN) effect, as previously described in patients with CADINS. Five other family members were affected by severe atopy associated with the above variant, but not hypogammaglobulinemia. Malignancies occurred in two generations: an HPV-positive squamous cell carcinoma and a cutaneous T-cell lymphoma. So far, one patient is under treatment with dupilumab, which has shown marked benefit in controlling severe eczema. Conclusion: The phenotypic spectrum associated with heterozygous CARD11 DN mutations is broad. Partial T-cell deficiency, diminished IFN-γ cytokine and increased IL-4 production, were identified as disease-causing mechanisms. Malignant disease associated with germline CARD11 DN variants has only been reported sporadically. HPV vaccination in teenage years, and cytology screening analogous with routine cervical swabs may be recommended. Treatment with dupilumab, a monoclonal antibody blocking interleukin-4- and interleukin-13 signaling, may be of benefit in controlling severe and extended AD for some patients as reported for STAT3 loss-of-function.

Biallelic truncating variants in ATP9A cause a novel neurodevelopmental disorder involving postnatal microcephaly and failure to thrive.

BACKGROUND: Genes implicated in the Golgi and endosomal trafficking machinery are crucial for brain development, and mutations in them are particularly associated with postnatal microcephaly (POM). METHODS: Exome sequencing was performed in three affected individuals from two unrelated consanguineous families presenting with delayed neurodevelopment, intellectual disability of variable degree, POM and failure to thrive. Patient-derived fibroblasts were tested for functional effects of the variants. RESULTS: We detected homozygous truncating variants in ATP9A. While the variant in family A is predicted to result in an early premature termination codon, the variant in family B affects a canonical splice site. Both variants lead to a substantial reduction of ATP9A mRNA expression. It has been shown previously that ATP9A localises to early and recycling endosomes, whereas its depletion leads to altered gene expression of components from this compartment. Consistent with previous findings, we also observed overexpression of ARPC3 and SNX3, genes strongly interacting with ATP9A. CONCLUSION: In aggregate, our findings show that pathogenic variants in ATP9A cause a novel autosomal recessive neurodevelopmental disorder with POM. While the physiological function of endogenous ATP9A is still largely elusive, our results underline a crucial role of this gene in endosomal transport in brain tissue.

Whole-genome sequencing of a sporadic primary immunodeficiency cohort.

Primary immunodeficiency (PID) is characterized by recurrent and often life-threatening infections, autoimmunity and cancer, and it poses major diagnostic and therapeutic challenges. Although the most severe forms of PID are identified in early childhood, most patients present in adulthood, typically with no apparent family history and a variable clinical phenotype of widespread immune dysregulation: about 25% of patients have autoimmune disease, allergy is prevalent and up to 10% develop lymphoid malignancies1-3. Consequently, in sporadic (or non-familial) PID genetic diagnosis is difficult and the role of genetics is not well defined. Here we address these challenges by performing whole-genome sequencing in a large PID cohort of 1,318 participants. An analysis of the coding regions of the genome in 886 index cases of PID found that disease-causing mutations in known genes that are implicated in monogenic PID occurred in 10.3% of these patients, and a Bayesian approach (BeviMed4) identified multiple new candidate PID-associated genes, including IVNS1ABP. We also examined the noncoding genome, and found deletions in regulatory regions that contribute to disease causation. In addition, we used a genome-wide association study to identify loci that are associated with PID, and found evidence for the colocalization of-and interplay between-novel high-penetrance monogenic variants and common variants (at the PTPN2 and SOCS1 loci). This begins to explain the contribution of common variants to the variable penetrance and phenotypic complexity that are observed in PID. Thus, using a cohort-based whole-genome-sequencing approach in the diagnosis of PID can increase diagnostic yield and further our understanding of the key pathways that influence immune responsiveness in humans.

Plasma Kynurenine Predicts Severity and Complications of Heart Failure and Associates with Established Biochemical and Clinical Markers of Disease.

BACKGROUND: Kynurenine, a metabolite of the L-tryptophan pathway, plays a pivotal role in neuro-inflammation, cancer immunology, and cardiovascular inflammation, and has been shown to predict cardiovascular events. OBJECTIVES: It was our objective to increase the body of data regarding the value of kynurenine as a biomarker in chronic heart failure (CHF). METHODS: We investigated the predictive value of plasma kynurenine in a CHF cohort (CHF, n = 114); in a second cohort of defibrillator carriers with CHF (AICD, n = 156), we determined clinical and biochemical determinants of the marker which was measured by enzyme immunoassay. RESULTS: In the CHF cohort, both kynurenine and NT-proBNP increased with NYHA class. Univariate binary logistic regression showed kynurenine to predict death within a 6-month follow-up (OR 1.43, 95% CI 1.03-2.00, p = 0.033) whereas NT-proBNP did not contribute significantly. Kynurenine, like NT-proBNP, was able to discriminate at a 30% threshold of left ventricular ejection fraction (LVEF; AUC-ROC, both 0.74). Kynurenine correlated inversely with LVEF (ϱ = -0.394), glomerular filtration fraction (GFR; ϱ = -0.615), and peak VO2 (ϱ = -0.626). Moreover, there was a strong correlation of kynurenine with NT-proBNP (ϱ = 0.615). In the AICD cohort, multiple linear regression analysis demonstrated highly significant associations of kynurenine with GFR, hsCRP, and tryptophan, as well as a significant impact of age. CONCLUSIONS: This work speaks in favor of kynurenine being a new and valuable biomarker of CHF, with particular attention placed on its ability to predict mortality and reflect exercise capacity.