Mild Disease Phenotype Research Articles

Клинические особенности патогенного варианта нуклеотидной последовательности L138ins в гене CFTR при муковисцидозе

In this study, we analyzed phenotypic manifestations and clinical course of cystic fibrosis (CF) in patients with the pathogenic variant L138ins of the CFTR gene. The L138ins variant is rarely detected in CF patients worldwide, but is quite common in different regions of the Russian Federation, particularly in the Middle Urals. Before the neonatal screening implementation, the majority of CF patients with the L138ins variant were diagnosed late because of the mild disease course and dubious results of sweat tests. Such patients usually have elevated levels of immunoreactive trypsinogen (IRT) in the neonatal period, which enables early diagnosis; however, false-negative results in CF patients have also been reported. There were cases of male infertility among CF patients with the L138ins variant, while women had their reproductive function preserved. There were also cases of asymptomatic pancreatic hyperenzymemia in children. Respiratory infections caused by Pseudomonas aeruginosa are not very common in this group of patients. However, adult patients have more severe respiratory manifestations (even with a fatal outcome) than children. Thus, despite the mild disease phenotype in patients with the L138ins variant, the residual function of the protein is not sufficient to ensure normal functioning of lungs. Key words: cystic fibrosis, pathogenic CFTR variants, L138ins

Reversion Mosaicism in Primary Immunodeficiency Diseases.

Reversion mosaicism has been reported in an increasing number of genetic disorders including primary immunodeficiency diseases. Several mechanisms can mediate somatic reversion of inherited mutations. Back mutations restore wild-type sequences, whereas second-site mutations result in compensatory changes. In addition, intragenic recombination, chromosomal deletions, and copy-neutral loss of heterozygosity have been demonstrated in mosaic individuals. Revertant cells that have regained wild-type function may be associated with milder disease phenotypes in some immunodeficient patients with reversion mosaicism. Revertant cells can also be responsible for immune dysregulation. Studies identifying a large variety of genetic changes in the same individual further support a frequent occurrence of reversion mosaicism in primary immunodeficiency diseases. This phenomenon also provides unique opportunities to evaluate the biological effects of restored gene expression in different cell lineages. In this paper, we review the recent findings of reversion mosaicism in primary immunodeficiency diseases and discuss its clinical implications.

Characterization of Alzheimer's disease-like neuropathology in Duchenne's muscular dystrophy using the DBA/2J mdx mouse model.

Duchenne muscular dystrophy (DMD) is a progressive muscle wasting disorder caused by a mutation in the dystrophin gene. In addition to muscle pathology, some patients with DMD will exhibit cognitive impairments with severity being linked to age and type of genetic mutation. Likewise, some studies have shown that mdx mice display impairments in spatial memory compared with wild‐type (WT) controls, while others have not observed any such effect. Most studies have utilized the traditional C57BL/10 (C57) mdx mouse, which exhibits a mild disease phenotype. Recently, the DBA/2J (D2) mdx mouse has emerged as a more severe and perhaps clinically relevant DMD model; however, studies examining cognitive function in these mice are limited. Thus, in this study we examined cognitive function in age‐matched C57 and D2 mdx mice along with their respective WT controls. Our findings show that 8‐ to 12‐week‐old C57 mdx mice did not display any differences in exploration time when challenged with a novel object recognition test. Conversely, age‐matched D2 mdx mice spent less time exploring objects in total as a well as less time exploring the novel object, suggestive of impaired recognition memory. Biochemical analyses of the D2 mdx brain revealed higher soluble amyloid precursor protein β (APPβ) and APP in the prefrontal cortex of mdx mice compared with WT, and lower soluble APPα in the hippocampus, suggestive of a shift towards amyloidogenesis and a similar pathogenesis to Alzheimer's disease. Furthermore, our study demonstrates the utility of the D2 mdx model in studying cognitive impairment.

Robust Virus-Specific Adaptive Immunity in COVID-19 Patients with SARS-CoV-2 \u0394382 Variant Infection

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) that have become dominant as the pandemic progresses bear the ORF8 mutation together with multiple spike mutations. A 382-nucleotide deletion (Δ382) in the ORF7b and ORF8 regions has been associated with milder disease phenotype and less systemic inflammation in COVID-19 patients. However, its impact on host immunity against SARS-CoV-2 remains undefined. Here, RNA-sequencing was performed to elucidate whole blood transcriptomic profiles and identify contrasting immune signatures between patients infected with either wildtype or Δ382 SARS-CoV-2 variant. Interestingly, the immune landscape of Δ382 SARS-CoV-2 infected patients featured an increased adaptive immune response, evidenced by enrichment of genes related to T cell functionality, a more robust SARS-CoV-2-specific T cell immunity, as well as a more rapid antibody response. At the molecular level, eukaryotic initiation factor 2 signaling was found to be upregulated in patients bearing Δ382, and its associated genes were correlated with systemic levels of T cell-associated and pro-inflammatory cytokines. This study provides more in-depth insight into the host–pathogen interactions of ORF8 with great promise as a therapeutic target to combat SARS-CoV-2 infection.

Donor Age and Red Cell Age Contribute to the Variance in Lorrca Indices in Healthy Donors for Next Generation Ektacytometry: A Pilot Study

The ability of red blood cells (RBCs) to transport gases, their lifespan as well as their rheological properties invariably depend on the deformability, hydration, and membrane stability of these cells, which can be measured by Laser optical rotational red cell analyser (Lorrca® Maxsis, RR Mechatronics). The osmoscan mode of Lorrca is currently used in diagnosis of rare anemias in clinical laboratories. However, a broad range of normal values for healthy subjects reduces the sensitivity of this method for diagnosis of mild disease phenotype. In this pilot study, we explored the impact of age and gender of 45 healthy donors, as well as RBC age on the Lorrca indices. Whereas gender did not affect the Lorrca indices in our study, the age donors had a profound effect on the O_hyper parameter. To study the impact of RBC age on the osmoscan parameters, we have isolated low (L)-, medium (M)-, or high (H)- density fractions enriched with young, mature, and senescent RBCs, respectively, and evaluated the influence of RBC age-related properties, such as density, morphology, and redox state, on the osmoscan indices. As before, O_hyper was the most sensitive parameter, dropping markedly with an increase in RBC density and age. Senescence was associated with a decrease in deformability (EI_max) and tolerability to low and high osmolatites (Area). L-fraction was enriched with reticulocytes and cells with high projected area and EMA staining, but also contained a small number of cells small in projected area and most likely, terminally senescent. L-fraction was on average slightly less deformable than mature cells. The cells from the L-fraction produced more oxidants and NO than all other fractions. However, RBCs from the L-fraction contained maximal levels of reduced thiols compared to other fractions. Our study suggests that reference values for O_hyper should be age-stratified, and, most probably, corrected for the average RBC age. Further multi-center study is required to validate these suggestions before implementing them into clinical practice.

F1099L-CFTR (c.3297C>G) has Impaired Channel Function and Associates with Mild Disease Phenotypes in Two Pediatric Patients.

(1) Background: many rare cystic fibrosis transmembrane conductance regulator (CFTR) mutations remain poorly characterized with regard to functional consequences of the mutation. We present the clinical features of two pediatric cystic fibrosis (CF) subjects who are heterozygous for F1099L (c.3297C>G), one with G551D (a class III mutation) and one with 3849 + 10kbC->T (a class V mutation). We also identified the molecular defect(s) that are associated with F1099L mutation to correlate with the clinical features that we observed; (2) Methods: clinical findings and history were extracted from the electronic medical record and de-identified. F1099L-CFTR protein expression level and maturation status, channel function, and the effects of CFTR modulation on these characteristics were investigated using western blotting and iodide efflux assay; (3) Results: these two subjects have mild CF phenotypes when F1099L is combined with two known disease-causing mutations. F1099L-CFTR has a moderate defect in processing and maturation, causing fewer CFTR channels at the cell surface and, therefore, impaired channel activities. These defects could be effectively corrected using VX-809 (lumacaftor); and, (4) Conclusions: our biochemical data correlate with the disease manifestations and suggest that F1099L is potentially a CF-causing mutation. The study expands our knowledge of rare CFTR mutations and may help in developing effective therapies for subjects with F1099L mutation.

Atypical Presentations of IPEX: Expect the Unexpected

Immune dysregulation, polyendocrinopathy, and enteropathy, X-linked (IPEX) syndrome is a rare disorder that has become a model of monogenic autoimmunity. IPEX is caused by mutations in FOXP3 gene, a master regulator of regulatory T cells (Treg). Cases reported in the last 20 years demonstrate that IPEX clinical spectrum encompasses more than the classical triad of early-onset intractable diarrhea, type 1 diabetes (T1D) and eczema. Atypical cases of IPEX include patients with late-onset of symptoms, single-organ involvement, mild disease phenotypes or rare clinical features (e.g., atrophic gastritis, interstitial lung disease, nephropathy etc.). Several atypical presentations have recently been reported, suggesting that IPEX incidence might be underestimated. Immunosuppression (IS) treatment strategies can control the disease, however at the moment allogeneic hematopoietic stem cell transplantation (HSCT) is the only available definitive cure, therefore it is important to achieve a prompt diagnosis. This review aims to describe unusual clinical phenotypes, beyond classical IPEX. Overall, our analysis contributes to increase awareness and finally improve diagnosis and treatment intervention in IPEX in order to ensure a good quality of life.

Genetic polymorphism of BCL11A (rs11886868) in Egyptian patients with β-thalassemia

ObjectivesTo study the effect of BCL11A (rs11886868) gene polymorphism on clinical status of Egyptian patients with β-thalassemia.Backgroundβ-thalassemia is a genetic disorder that results from β-globin gene mutations leading to defective synthesis of adult hemoglobin (Hb A). Clinical consequences vary tremendously from nearly asymptomatic to severely anemic and transfusion-dependent patients. Phenotypic variations have been linked not only to the type of β-globin gene mutations and amount of synthesized Hb A but also to recently discovered genetic modifiers mapping outside the β-globin gene cluster including BCL11A gene polymorphism. These modifiers are associated with increased fetal hemoglobin (Hb F) levels.Patients and methodsBlood samples were collected from 120 patients with β-thalassemia before transfusion of blood. Complete blood count, quantitative measurement of different Hb types by high-performance liquid chromatography, and analysis of single nucleotide polymorphism rs11886868 in the BCL11A gene by Taqman single nucleotide polymorphism genotyping assay and real-time PCR were done.ResultsThe genotype distribution of BCL11A gene polymorphism showed low frequency of CC genotype (15%) among Egyptian patients with β-thalassemia. The CT genotype was 41.7% and TT genotype was 43.3%. There was a significant relation between BCL11A (rs11886868) genotypes and Hb F levels, with the highest Hb F levels were observed in the CC genotype followed by CT genotype, whereas Hb F levels were the lowest in TT genotype. Patients with CC genotype had mild disease phenotype owing to increased Hb F production. Hb F utilizes some of the free α-chain and ameliorates clinical presentation.ConclusionScreening of BCL11A gene variants may be used as a marker for severity risk in newly diagnosed patients with β-thalassemia and as a predictor of clinical outcome of this disorder.

Pediatric Patients with Sickle Cell Disease at Harbor-UCLA & Early Experience of L-Glutamine Therapy

Background.Sickle cell disease (SCD) affects millions of people worldwide, including >100,000 Americans, and is often complicated by acute crises. Complex pathophysiology makes it challenging to ameliorate SCD severity, which can be influenced by hydration and disease-modifying agents such as hydroxyurea (HU). Due to the increased metabolic demands of chronic illness, optimal nutrition and presumably antioxidant L-glutamine (Gln) may further contribute to disease control. Thus, we hypothesized that better nutrition and Gln adherence may reduce occurrences of pain crises in SCD. Methods.An IRB-approved retrospective review of pediatric patients with SCD ≥1 y of age was conducted at our institution, along with voluntary nutrition surveys. Evaluations were carried out for associations between disease severity and clinical/laboratory variables representing nutrition, growth, hematologic parameters [fetal hemoglobin (HbF), mean corpuscular volume (MCV)], and treatment compliance (with HU and/or Gln). Results.Preliminary analyses included data from 50 SCD patients (25 F/25 M), with a mean age of 9.1 ±7 y and a mean BMI of 56.4 ±32.6% (±SDEV). Sixty percent of the patients had HbSS/Sß0 (32%-HbSC and 8%-HbSß+). The average number of annual pain crises (APC, 0.97 ±1.14) requiring hospital visits or admissions per patient rose with age. HbF expectedly dropped with age. HbF levels <10% in teenage and older patients were associated with a ≥2-fold higher APC, compared to younger patients (despite similar proportions of HbSS/Sß0). Proper hydration and nutrition were reported by 69% and 43% of 35 survey participants, respectively. APC values for 3 main groups were: - 0.87 ±1.1 for well hydrated/well nourished (n=14, 3.1 ±2.3 y) - 1.4 ±2 for well hydrated/poorly nourished (n=10, 11 ±6.4 y) - 1.97 ±2 for poorly hydrated/poorly nourished (n=8, 13 ±5.4 y). There were no correlations between caloric intake and BMI. However, 20% of surveyed patients (12 ±7.8 y) had Z-scores lower than -1 SD for both height and weight. Their mean APC was significantly higher (2.5 ±2.5vs.1 ±1.3,p=0.03 byt-test). Their prealbumin levels trended lower than normal for age, and were more diminished in older patients. Nearly 60% of our patients were on HU (80% with HbSS/Sß0, age 10.8 ±7.4 y). Good HU adherence was reported by 22 patients, typically ≥90%, which was associated with higher MCVs (92 ±9.6 vs. 74 ±10 f/L,p<0.01), a trend toward higher HbF levels, and younger ages (15 vs. 9% and 9.7 ±7 vs. 14 ±7.7 y,p=NS). The majority (83%) of our patients 5 y of age or older were prescribed Gln, and 70% of the prescriptions were dispensed. Some refused Gln due to abdominal pain or taste, and a quarter of patients reported <50% Gln intake while on both HU and Gln. Thus, overall Gln compliance in 23-months was ≥70% in 12 patients. Patients were excluded while on chronic transfusion. Of 10 evaluable patients, 6 (8.8 ±2.2 y) had a significantly lower APC with Gln (mean APC decrease 0.9 to 0.2,p=0.016 by pairedt-test) coupled with a 12% rise in prealbumin (14.1 to 15.8 mg/dL;p=0.1). Conclusions.Well-nourished/hydrated patients were younger and had a milder disease phenotype, whereas more severe disease was seen in poorly nourished older patients, often with suboptimal compliance. L-Glutamine can be a clinically meaningful addition to HU and should be further studied in pediatric SCD. Disclosures No relevant conflicts of interest to declare.

Strain-dependent disease and response to favipiravir treatment in mice infected with Chikungunya virus

Antiviral countermeasures are needed to reduce the morbidity associated with Chikungunya virus (CHIKV) infection. This arbovirus reemerged in 2004 and causes periodic outbreaks in various areas throughout the world. While infection is rarely lethal, the majority of people infected with the virus develop a hallmark arthralgia as well as other disease manifestations. The virus is classified within three phylogenetic groups, namely, West African, East/Central/South African (ECSA), and Asian. Six strains of CHIKV covering the three phylogenetic groups were studied for their replication in cell culture, their ability to cause disease in susceptible mouse strains and susceptibility to antiviral treatment. Differential replication kinetics were observed for various CHIKV isolates in cell culture, which coincided with a decreased sensitivity to antiviral treatment as compared with ECSA and Asian clade viruses. This was confirmed in mouse infection studies with severe disease observed in mice infected with West African clade viruses, mild disease phenotype after infection with Asian clade viruses and an intermediate disease severity associated with ECSA virus infection. We also tested a broadly active antiviral, Favipiravir (T-705), which activity was inversely proportional to disease severity. These data suggest that some clades of CHIKV may cause more severe disease and may be more difficult to treat.

Dynamic nature of somatic chromosomal mosaicism, genetic-environmental interactions and therapeutic opportunities in disease and aging

BackgroundSomatic chromosomal mosaicism is the presence of cell populations differing with respect to the chromosome complements (e.g. normal and abnormal) in an individual. Chromosomal mosaicism is associated with a wide spectrum of disease conditions and aging. Studying somatic genome variations has indicated that amounts of chromosomally abnormal cells are likely to be unstable. As a result, dynamic changes of mosaicism rates occur through ontogeny. Additionally, a correlation between disease severity and mosaicism rates appears to exist. High mosaicism rates are usually associated with severe disease phenotypes, whereas low-level mosaicism is generally observed in milder disease phenotypes or in presumably unaffected individuals. Here, we hypothesize that dynamic nature of somatic chromosomal mosaicism may result from genetic-environmental interactions creating therapeutic opportunities in the associated diseases and aging.ConclusionGenetic-environmental interactions seem to contribute to the dynamic nature of somatic mosaicism. Accordingly, an external influence on cellular populations may shift the ratio of karyotypically normal and abnormal cells in favor of an increase in the amount of cells without chromosome rearrangements. Taking into account the role of somatic chromosomal mosaicism in health and disease, we have hypothesized that artificial changing of somatic mosaicism rates may be beneficial in individuals suffering from the associated diseases and/or behavioral or reproductive problems. In addition, such therapeutic procedures might be useful for anti-aging strategies (i.e. possible rejuvenation through a decrease in levels of chromosomal mosaicism) increasing the lifespan. Finally, the hypothesis appears to be applicable to any type of somatic mosacism.

Immune profiles provide insights into respiratory syncytial virus disease severity in young children.

Respiratory syncytial virus (RSV) is associated with major morbidity in infants, although most cases result in mild disease. The pathogenesis of the disease is incompletely understood, especially the determining factors of disease severity. A better characterization of these factors may help with development of RSV vaccines and antivirals. Hence, identification of a "safe and protective" immunoprofile induced by natural RSV infection could be used as a as a surrogate of ideal vaccine-elicited responses in future clinical trials. In this study, we integrated blood transcriptional and cell immune profiling, RSV loads, and clinical data to identify factors associated with a mild disease phenotype in a cohort of 190 children <2 years of age. Children with mild disease (outpatients) showed higher RSV loads, greater induction of interferon (IFN) and plasma cell genes, and decreased expression of inflammation and neutrophil genes versus children with severe disease (inpatients). Additionally, only infants with severe disease had increased numbers of HLA-DRlow monocytes, not present in outpatients. Multivariable analyses confirmed that IFN overexpression was associated with decreased odds of hospitalization, whereas increased numbers of HLA-DRlow monocytes were associated with increased risk of hospitalization. These findings suggest that robust innate immune responses are associated with mild RSV infection in infants.

Differential leukocyte count is associated with clinical phenotype in Parkinson's disease

IntroductionElevated proinflammatory cytokines are associated with disease progression in patients with Parkinson's disease (PD). The aim of study is to investigate whether components of peripheral blood leukocyte are associated with clinical symptoms in patients with de novo PD. MethodsWe analyzed data from 123 newly diagnosed de novo patients who had no focal and systemic inflammatory diseases. Associations between clinical symptoms and differential leukocyte count (DLC) or DLC associated peripheral inflammatory biomarkers were examined. ResultsAltered DLC and DLC associated peripheral inflammatory biomarkers were associated with PD related symptoms even though there was no sign of clinical inflammation. After controlling for covariables, olfaction and body mass index (BMI) were inversely associated with percentage of neutrophil, neutrophil to lymphocyte ratio, derived neutrophil to lymphocyte ratio, and positively associated with percentage of lymphocyte, lymphocyte to monocyte ratio. Patients with tremor-dominant or mixed type had lower peripheral inflammatory indices than those with akinetic rigid type. ConclusionComponents of peripheral blood leukocytes reflect some clinical symptoms of PD. Patients with normosmia, tremor-dominant or mixed type, and patients without low BMI have low peripheral inflammatory indices. Relative mild peripheral inflammation may play one of major roles in developing mild disease phenotype in these patients.

Life-threatening presentations of propionic acidemia due to the Amish PCCB founder variant

Although individuals of Amish descent with propionic acidemia (PA) are generally thought to have a milder disease phenotype, we now have a better understanding of the natural history of PA in this population. Here we describe two Amish patients with emergent presentations of PA, one with metabolic decompensation and another with cardiogenic shock. PA can present with life-threatening metabolic decompensation or an adult-onset severe cardiomyopathy. We discuss critical clinical implications of this observation.

CMT disease severity correlates with mutation-induced open conformation of histidyl-tRNA synthetase, not aminoacylation loss, in patient cells

Aminoacyl-transfer RNA (tRNA) synthetases (aaRSs) are the largest protein family causatively linked to neurodegenerative Charcot-Marie-Tooth (CMT) disease. Dominant mutations cause the disease, and studies of CMT disease-causing mutant glycyl-tRNA synthetase (GlyRS) and tyrosyl-tRNA synthetase (TyrRS) showed their mutations create neomorphic structures consistent with a gain-of-function mechanism. In contrast, based on a haploid yeast model, loss of aminoacylation function was reported for CMT disease mutants in histidyl-tRNA synthetase (HisRS). However, neither that nor prior work of any CMT disease-causing aaRS investigated the aminoacylation status of tRNAs in the cellular milieu of actual patients. Using an assay that interrogated aminoacylation levels in patient cells, we investigated a HisRS-linked CMT disease family with the most severe disease phenotype. Strikingly, no difference in charged tRNA levels between normal and diseased family members was found. In confirmation, recombinant versions of 4 other HisRS CMT disease-causing mutants showed no correlation between activity loss in vitro and severity of phenotype in vivo. Indeed, a mutation having the most detrimental impact on activity was associated with a mild disease phenotype. In further work, using 3 independent biophysical analyses, structural opening (relaxation) of mutant HisRSs at the dimer interface best correlated with disease severity. In fact, the HisRS mutation in the severely afflicted patient family caused the largest degree of structural relaxation. These data suggest that HisRS-linked CMT disease arises from open conformation-induced mechanisms distinct from loss of aminoacylation.

Compensated pathogenic variants in coagulation factors VIII and IX present complex mapping between molecular impact and hemophilia severity

Compensated pathogenic deviations (CPDs) are sequence variants that are pathogenic in humans but neutral in other species. In recent years, our molecular understanding of CPDs has advanced substantially. For example, it is known that their impact on human proteins is generally milder than that of average pathogenic mutations and that their impact is suppressed in non-human carriers by compensatory mutations. However, prior studies have ignored the evolutionarily relevant relationship between molecular impact and organismal phenotype. Here, we explore this topic using CPDs from FVIII and FIX and data concerning carriers’ hemophilia severity. We find that, regardless of their molecular impact, these mutations can be associated with either mild or severe disease phenotypes. Only a weak relationship is found between protein stability changes and severity. We also characterize the population variability of hemostasis proteins, which constitute the genetic background of FVIII and FIX, using data from the 1000 Genome project. We observe that genetic background can vary substantially between individuals in terms of both the amount and nature of genetic variants. Finally, we discuss how these results highlight the need to include new terms in present models of protein evolution to explain the origin of CPDs.

Somatic genetic rescue in Mendelian haematopoietic diseases.

Somatic mutations occur spontaneously in normal individuals and accumulate throughout life. These genetic modifications contribute to progressive ageing phenotypes and are directly involved in cancer development. However, a growing number of studies of Mendelian haematopoietic disorders indicate that somatic genetic events can offset the pathogenic effect of germline mutations at the cellular level, leading to genetic mosaicism and, in some cases, resulting in a milder disease phenotype. Notably, spontaneous genetic events that confer a positive effect on cells do not always benefit the individual, for whom the effects can be neutral or even clinically detrimental. These somatic genetic rescue events have important diagnostic, therapeutic and clinical consequences and constitute valuable models for studying the differentiation and/or homeostasis of haematopoietic lineages.

Recent advances in the management of antineutrophil cytoplasmic antibody-associated vasculitis

The prognosis of antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has remarkably improved from an almost uniformly fatal disease about three decades back, to a chronic manageable disease with survival rates in excess of 80%. Induction of remission largely relies on cyclophosphamide or rituximab-based regimens, although emerging data suggest some potential role of mycophenolate mofetil (MMF), especially in milder disease phenotypes. Recent emphasis has shifted to exploration of treatment regimens minimizing dosage and duration of corticosteroid exposure, or replacing corticosteroids altogether with agents like avacopan, in an effort to ameliorate risks due to glucocorticoids as well as minimize damage accrual. Maintenance regimens traditionally have used azathioprine, methotrexate, or less commonly, MMF. However, rituximab is emerging as a useful maintenance agent, with the advantage of single-dose administration 6 monthly. Dosing interval for rituximab maintenance is another area of active research, with emerging literature suggesting the effectiveness of a dosing schedule based on B-cell repopulation or rise in ANCA titers. Long-term considerations for patients with AAV include the risk of infections (which can be minimized with alternate-day cotrimoxazole therapy), hypogammaglobulinemia in patients on rituximab, and accrual of damage, including drug-related damage (such as diabetes and osteoporosis) and malignancies. Ongoing clinical trials attempt to decipher the role of plasma exchange, as well as delineate the exact role of newer steroid-sparing therapeutic modalities such as avacopan. Recent clinical guidelines for the management of AAV from multiple societies, including the European League against Rheumatism and the British Society for Rheumatology, provide common treatment recommendations for AAV management.

Patients with cystic fibrosis having a residual function mutation: Data from the Italian registry.

CFTR mutations permitting residual function (RF) of the CFTR protein are disease-causing. These mutations are associated with a pneumopathy that is delayed in onset and is slower in progression than are more common forms of cystic fibrosis (CF), although the disease may become severe in some patients. RF mutations are among the most frequent in Italy, thus encouraging investigation of their prevalence and associated phenotypes. Data from the Italian Registry were used to compare patients with at least one RF mutation with those homozygous for F508del. A total of 806 patients bearing at least one RF mutation were identified among 5204 registered patients (15.5%). The RF patients were older than the F508del homozygotes (median age 26.0 years vs 19.8 years, respectively), with a higher median age at diagnosis (6.3 years vs 0.2 years, respectively) and a lower median sweat chloride value (76.0 mmol/L vs 100.0 mmol/L, respectively). In the RF group, lung infections and comorbidities were less prevalent than those in the F508del homozygotes, while better FEV1 and nutritional status were observed at all ages. Within the RF group, RF/F508del subjects showed more severe pneumopathy than did patients with RF/other mutations. In particular, the 3849 + 10kbC → T/F508del subjects had worse FEV1 and a higher prevalence of lung infections than did patients with other genotypes. Patients with RF mutations are numerous in Italy and have a milder disease phenotype than do F508del homozygotes. Inside the RF group, F508del heterozygotes and, in particular, 3849 + 10kbC → T/F508del patients showed more severe pneumopathy.

Modulating membrane fluidity corrects Batten disease phenotypes in vitro and in vivo

The neuronal ceroid lipofuscinoses are a class of inherited neurodegenerative diseases characterized by the accumulation of autofluorescent storage material. The most common neuronal ceroid lipofuscinosis has juvenile onset with rapid onset blindness and progressive degeneration of cognitive processes. The juvenile form is caused by mutations in the CLN3 gene, which encodes the protein CLN3. While mouse models of Cln3 deficiency show mild disease phenotypes, it is apparent from patient tissue- and cell-based studies that its loss impacts many cellular processes. Using Cln3 deficient mice, we previously described defects in mouse brain endothelial cells and blood-brain barrier (BBB) permeability. Here we expand on this to other components of the BBB and show that Cln3 deficient mice have increased astrocyte endfeet area. Interestingly, this phenotype is corrected by treatment with a commonly used GAP junction inhibitor, carbenoxolone (CBX). In addition to its action on GAP junctions, CBX has also been proposed to alter lipid microdomains. In this work, we show that CBX modifies lipid microdomains and corrects membrane fluidity alterations in Cln3 deficient endothelial cells, which in turn improves defects in endocytosis, caveolin-1 distribution at the plasma membrane, and Cdc42 activity. In further work using the NIH Library of Integrated Network-based Cellular Signatures (LINCS), we discovered other small molecules whose impact was similar to CBX in that they improved Cln3-deficient cell phenotypes. Moreover, Cln3 deficient mice treated orally with CBX exhibited recovery of impaired BBB responses and reduced autofluorescence. CBX and the compounds identified by LINCS, many of which have been used in humans or approved for other indications, may find therapeutic benefit in children suffering from CLN3 deficiency through mechanisms independent of their original intended use.