Marked overlap of four genetic syndromes with dyskeratosis congenita confounds clinical diagnosis

Financial support provided by The Medical Research Council-MR/K000292/1, Children with Cancer- 2013/144 and Blood Wise-14032 (AJW, LC, SC, AE, TV, HT and ID). KMG is supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Centre

Targeted high-throughput sequencing for genetic diagnostics of hemophagocytic lymphohistiocytosis

Background: Hemophagocytic lymphohistiocytosis (HLH) is a rapid-onset, potentially fatal hyperinflammatory syndrome. A prompt molecular diagnosis is crucial for appropriate clinical management. Here, we validated and prospectively evaluated a targeted high-throughput sequencing approach for HLH diagnostics. Methods: A high-throughput sequencing strategy of 12 genes linked to HLH was validated in 13 patients with previously identified HLH-associated mutations and prospectively evaluated in 58 HLH patients. Moreover, 2504 healthy individuals from the 1000 Genomes project were analyzed in silico for variants in the same genes. Results: Analyses revealed a mutation detection sensitivity of 97.3 %, an average coverage per gene of 98.0 %, and adequate coverage over 98.6 % of sites previously reported as mutated in these genes. In the prospective cohort, we achieved a diagnosis in 22 out of 58 patients (38 %). Genetically undiagnosed HLH patients had a later age at onset and manifested higher frequencies of known secondary HLH triggers. Rare, putatively pathogenic monoallelic variants were identified in nine patients. However, such monoallelic variants were not enriched compared with healthy individuals. Conclusions: We have established a comprehensive high-throughput platform for genetic screening of patients with HLH. Almost all cases with reduced natural killer cell function received a diagnosis, but the majority of the prospective cases remain genetically unexplained, highlighting genetic heterogeneity and environmental impact within HLH. Moreover, in silico analyses of the genetic variation affecting HLH-related genes in the general population suggest caution with respect to interpreting causality between monoallelic mutations and HLH. A complete understanding of the genetic susceptibility to HLH thus requires further in-depth investigations, including genome sequencing and detailed immunological characterization.Peer reviewe

Outcomes and treatment strategies for autoimmunity and hyperinflammation in patients with RAG deficiency

BACKGROUND: While autoimmunity and hyperinflammation secondary to recombinase activating gene (RAG) deficiency have been associated with delayed diagnosis and even death, our current understanding is limited primarily to small case series. OBJECTIVE: Understand the frequency, severity, and treatment responsiveness of autoimmunity and hyperinflammation in RAG deficiency. METHODS: In reviewing the literature and our own database, we identified 85 patients with RAG deficiency, reported between 2001 and 2016, and compiled the largest case series to date of 63 patients with prominent autoimmune and/or hyperinflammatory pathology. RESULTS: Diagnosis of RAG deficiency was delayed a median of 5 years from the first clinical signs of immune dysregulation. The majority of patients (55.6%) presented with more than one autoimmune or hyperinflammatory complication, with the most common etiologies being cytopenias (84.1%), granulomas (23.8%), and inflammatory skin disorders (19.0%). Infections, including live viral vaccinations, closely preceded the onset of autoimmunity in 28.6% of cases. Autoimmune cytopenias had early onset (median 1.9, 2.1, and 2.6 years for autoimmune hemolytic anemia (AIHA), immune thrombocytopenia (ITP) and autoimmune neutropenia (AN), respectively) and were refractory to intravenous immunoglobulin, steroids, and rituximab in the majority of cases (64.7%, 73.7%, and 71.4% for AIHA, ITP, and AN, respectively). Evans syndrome specifically was associated with lack of response to first-line therapy. Treatment-refractory autoimmunity/hyperinflammation prompted hematopoietic stem cell transplantation in 20 patients. CONCLUSIONS: Autoimmunity/hyperinflammation can be a presenting sign of RAG deficiency and should prompt further evaluation. Multi-lineage cytopenias are often refractory to immunosuppressive treatment and may require hematopoietic cell transplantation for definitive management

Protective effect of magnesium supplementation on experimental 3-methyl cholantrene-induced fibrosarcoma and changes in tissue magnesium distribution during carcinogenesis in rats

In this study, we wanted to examine the effect of magnesium (Mg2+) supplementation on the experimental 3-methyl cholantrene (3-MC)-induced fibrosarcoma and alterations in (Mg2+) distribution in several tissues of the rats, during carcinogenesis. It was determined that serum and tissue (Mg2+) levels of the rats in (Mg2+)-supplemented diet group were higher than those of the rats in the (Mg2+)-nonsupplemented and control groups. The mean time of fibrosarcoma development for (Mg2+)-supplemented group was longer than (Mg2+)-nonsupplemented group (p < 0.05). Symptoms of hypermagnesemia were not observed in any of the rats. These results suggests that dietary (Mg2+) supplementation may have a partial anticarcinogenic effect on experimental 3-MC-induced fibrosarcoma by prolongation of the latent period of carcinogenesis