Lithium-Associated Kidney Failure: Predictors and Outcomes.

Introduction: Despite the widespread use of lithium for bipolar disorders and depression, little is known about the characteristics of patients with lithium-associated kidney failure receiving kidney replacement therapy (KRT). Methods: We conducted a retrospective study using the Australian and New Zealand Dialysis and Transplant Registry (ANZDATA) to investigate the predictors and outcomes of patients with lithium-associated kidney failure receiving KRT. Results: A total of 437 patients with lithium-associated kidney failure were compared to 1280 ANZDATA allocated controls of patients with kidney failure not associated with lithium. Patients with lithium-associated kidney failure commenced KRT at significantly older age (62 ± 10 vs. 58 ± 15 years; P < 0.001) and were more likely to be European (93% vs. 68%, P < 0.001), to be female (63% vs. 40%, P < 0.001), and to live in a postcode with a higher socioeconomic status (SES) (P < 0.001). In patients with lithium-associated kidney failure, there were lower rates of coronary artery disease (17% vs. 37%, P < 0.001), peripheral vascular disease (7% vs. 25%, P < 0.001), cerebrovascular disease (8% vs. 14%, P = 0.004) and diabetes mellitus (16% vs. 47%, P < 0.001). There were no differences between first KRT modality, although kidney transplantation and retransplantation rates were lower (21% vs. 27%, P = 0.008; 0.2% vs 3%, P = 0.001) with shorter wait-times to first transplantation (20 months vs. 29 months, P = 0.02) in the patients with lithium-associated kidney failure. Rates of at least 1 rejection episode was comparable (21% vs. 22%, P = 0.85) between the 2 groups. In addition, there were no survival differences regardless of KRT modality between the 2 groups. Conclusion: Lithium-associated kidney failure represents a unique cohort which is predominantly older, female, European, with a higher SES and less comorbidities. Despite this, there are no differences in survival. Given the lower rate of transplantation, barriers to transplantation need further exploration.

Recommendations for risk allele evidence curation, classification, and reporting from the ClinGen Low Penetrance/Risk Allele Working Group.

PURPOSE: Genetic variants at the low end of the penetrance spectrum have historically been challenging to interpret because their high population frequencies exceed the disease prevalence of the associated condition, leading to a lack of clear segregation between the variant and disease. There is currently substantial variation in the classification of these variants, and no formal classification framework has been widely adopted. The Clinical Genome Resource Low Penetrance/Risk Allele Working Group was formed to address these challenges and promote harmonization within the clinical community. METHODS: The work presented here is the product of internal and community Likert-scaled surveys in combination with expert consensus within the Working Group. RESULTS: We formally recognize risk alleles and low-penetrance variants as distinct variant classes from those causing highly penetrant disease that require special considerations regarding their clinical classification and reporting. First, we provide a preferred terminology for these variants. Second, we focus on risk alleles and detail considerations for reviewing relevant studies and present a framework for the classification these variants. Finally, we discuss considerations for clinical reporting of risk alleles. CONCLUSION: These recommendations support harmonized interpretation, classification, and reporting of variants at the low end of the penetrance spectrum.

Cell-free hemoglobin triggers macrophage cytokine production via TLR4 and MyD88.

Cell-free hemoglobin (CFH) is elevated in the airspace of patients with acute respiratory distress syndrome (ARDS) and is sufficient to cause acute lung injury in a murine model. However, the pathways through which CFH causes lung injury are not well understood. Toll-like receptor 4 (TLR4) is a mediator of inflammation after detection of damage- and pathogen-associated molecular patterns. We hypothesized that TLR4 signaling mediates the proinflammatory effects of CFH in the airspace. After intratracheal CFH, BALBc mice deficient in TLR4 had reduced inflammatory cell influx into the airspace [bronchoalveolar lavage (BAL) cell counts, median TLR4 knockout (KO): 0.8 × 104/mL [IQR 0.4-1.2 × 104/mL], wild-type (WT): 3.0 × 104/mL [2.2-4.0 × 104/mL], P < 0.001] and attenuated lung permeability (BAL protein, TLR4KO: 289 µg/mL [236-320], WT: 488 µg/mL [422-536], P < 0.001). These mice also had attenuated production of interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α in the airspace. C57Bl/6 mice lacking TLR4 on myeloid cells only (LysM.Cre+/-TLR4fl/fl) had reduced cytokine production in the airspace after CFH, without attenuation of lung permeability. In vitro studies confirm that WT primary murine alveolar macrophages exposed to CFH (0.01-1 mg/mL) had dose-dependent increases in IL-6, IL-1 ß, CXC motif chemokine ligand 1 (CXCL-1), TNF-α, and IL-10 (P < 0.001). Murine MH-S alveolar-like macrophages show TLR4-dependent expression of IL-1ß, IL-6, and CXCL-1 in response to CFH. Primary alveolar macrophages from mice lacking TLR4 adaptor proteins myeloid differentiation primary response 88 (MyD88) or TIR-domain-containing adapter-inducing interferon-ß (TRIF) revealed that MyD88KO macrophages had 71-96% reduction in CFH-dependent proinflammatory cytokine production (P < 0.001), whereas macrophages from TRIFKO mice had variable changes in cytokine responses. These data demonstrate that myeloid TLR4 signaling through MyD88 is a key regulator of airspace inflammation in response to CFH.NEW & NOTEWORTHY Cell-free hemoglobin (CFH) is elevated in the airspace of most patients with acute respiratory distress syndrome and causes severe inflammation. Here, we identify that CFH contributes to macrophage-induced cytokine production via Toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) signaling. These data increase our knowledge of the mechanisms through which CFH contributes to lung injury and may inform development of targeted therapeutics to attenuate inflammation.

Acute and chronic lung inflammation drives changes in epithelial glycans.

Introduction: Asthma is the most common chronic inflammatory disease and it is characterized by leukocyte infiltration and tissue remodeling, with the latter generally referring to collagen deposition and epithelial hyperplasia. Changes in hyaluronin production have also been demonstrated, while mutations in fucosyltransferases reportedly limit asthmatic inflammation. Methods: Given the importance of glycans in cellular communication and to better characterize tissue glycosylation changes associated with asthma, we performed a comparative glycan analysis of normal and inflamed lungs from a selection of murine asthma models. Results: We found that among other changes, the most consistent was an increase in fucose-α1,3-N-acetylglucosamine (Fuc-α1,3-GlcNAc) and fucose-α1,2-galactose (Fuc-α1,2-Gal) motifs. Increases in terminal galactose and N-glycan branching were also seen in some cases, whereas no overall change in O-GalNAc glycans was observed. Increased Muc5AC was found in acute but not chronic models, and only the more human-like triple antigen model yielded increased sulfated galactose motifs. We also found that human A549 airway epithelial cells stimulated in culture showed similar increases in Fuc-α1,2-Gal, terminal galactose (Gal), and sulfated Gal, and this matched transcriptional upregulation of the α1,2-fucosyltransferase Fut2 and the α1,3-fucosyltransferases Fut4 and Fut7. Conclusions: These data suggest that airway epithelial cells directly respond to allergens by increasing glycan fucosylation, a known modification important for the recruitment of eosinophils and neutrophils.

Elective genomic testing: Practice resource of the National Society of Genetic Counselors.

Genetic counseling for patients who are pursuing genetic testing in the absence of a medical indication, referred to as elective genomic testing (EGT), is becoming more common. This type of testing has the potential to detect genetic conditions before there is a significant health impact permitting earlier management and/or treatment. Pre- and post-test counseling for EGT is similar to indication-based genetic testing. Both require a complete family and medical history when ordering a test or interpreting a result. However, EGT counseling has some special considerations including greater uncertainties around penetrance and clinical utility and a lack of published guidelines. While certain considerations in the selection of a high-quality genetic testing laboratory are universal, there are some considerations that are unique to the selection of a laboratory performing EGT. This practice resource intends to provide guidance for genetic counselors and other healthcare providers caring for adults seeking pre- or post-test counseling for EGT. Genetic counselors and other genetics trained healthcare providers are the ideal medical professionals to supply accurate information to individuals seeking counseling about EGT enabling them to make informed decisions about testing and follow-up.

D-bifunctional protein deficiency caused by splicing variants in a neonate with severe peroxisomal dysfunction and persistent hypoglycemia.

D-bifunctional protein (DBP) deficiency is a rare, autosomal recessive peroxisomal enzyme deficiency resulting in a high burden of morbidity and early mortality. Patients with DBP deficiency resemble those with a severe Zellweger phenotype, with neonatal hypotonia, seizures, craniofacial dysmorphisms, psychomotor delay, deafness, blindness, and death typically within the first 2 years of life, although patients with residual enzyme function can survive longer. The clinical severity of the disease depends on the degree of enzyme deficiency. Loss-of-function variants typically result in no residual enzyme activity; however, splice variants may result in protein with residual function. We describe a full-term newborn presenting with hypotonia, seizures, and unexplained hypoglycemia, who was later found to have rickets at follow up. Rapid whole genome sequencing identified two HSD17B4 variants in trans; one likely pathogenic variant and one variant of uncertain significance (VUS) located in the polypyrimidine tract of intron 13. To determine the functional consequence of the VUS, we analyzed RNA from the patient's father with RNA-seq which showed skipping of Exon 14, resulting in a frameshift mutation three amino acids from the new reading frame. This RNA-seq analysis was correlated with virtually absent enzyme activity, elevated very-long-chain fatty acids in fibroblasts, and a clinically severe phenotype. Both variants are reclassified as pathogenic. Due to the clinical spectrum of DBP deficiency, this provides important prognostic information, including early mortality. Furthermore, we add persistent hypoglycemia to the clinical spectrum of the disease, and advocate for the early management of fat-soluble vitamin deficiencies to reduce complications.

Design and Reporting Considerations for Genetic Screening Tests.

Testing asymptomatic individuals for unsuspected conditions is not new to the medical and public health communities. Protocols to develop screening tests are well established. However, the application of screening principles to inherited diseases presents unique challenges. Unlike most screening tests, the natural history and disease prevalence of most rare inherited diseases in an unselected population are unknown. It is difficult or impossible to obtain a truth set cohort for clinical validation studies. As a result, it is not possible to accurately calculate clinical positive and negative predictive values for likely pathogenic variants, which are commonly returned in genetic screening assays. In addition, many of the genetic conditions included in screening panels do not have clinical confirmatory tests. All these elements are typically required to justify the development of a screening test, according to the World Health Organization screening principles. Nevertheless, as the cost of DNA sequencing continues to fall, more individuals are opting to undergo genomic testing in the absence of a clinical indication. Despite the challenges, reasonable estimates can be deduced and used to inform test design strategies. Herein, we review basic test design principles and apply them to genetic screening.

Considerations for clinical curation, classification, and reporting of low-penetrance and low effect size variants associated with disease risk.

PURPOSE: Clinically relevant variants exhibit a wide range of penetrance. Medical practice has traditionally focused on highly penetrant variants with large effect sizes and, consequently, classification and clinical reporting frameworks are tailored to that variant type. At the other end of the penetrance spectrum, where variants are often referred to as "risk alleles," traditional frameworks are no longer appropriate. This has led to inconsistency in how such variants are interpreted and classified. Here, we describe a conceptual framework to begin addressing this gap. METHODS: We used a set of risk alleles to define data elements that can characterize the validity of reported disease associations. We assigned weight to these data elements and established classification categories expressing confidence levels. This framework was then expanded to develop criteria for inclusion of risk alleles on clinical reports. RESULTS: Foundational data elements include cohort size, quality of phenotyping, statistical significance, and replication of results. Criteria for determining inclusion of risk alleles on clinical reports include presence of clinical management guidelines, effect size, severity of the associated phenotype, and effectiveness of intervention. CONCLUSION: This framework represents an approach for classifying risk alleles and can serve as a foundation to catalyze community efforts for refinement.

A comparative study of patients' perceptions of genetic and genomic medicine services in California and Malaysia.

In the era of personalized and genomic medicine, awareness of patients with rare diseases is increasing as new approaches to diagnosis and treatment are developed. This study examined perceived barriers experienced by families with rare diseases and explored possible differences between participants in Malaysia and California, USA. The study involved N = 108 participants recruited in genetics clinic appointments at the University of Malaya Medical Center and three sites in Southern California. Participants completed a survey involving multiple choice and Likert scale items pertaining to perceived barriers to access genetics-related healthcare. Results from this study provide evidence of similar perceived barriers, despite differences in the two populations. Participants selected the expansion of healthcare provider knowledge of rare diseases to be the most beneficial approach to overcome perceived barriers. In both locations, it was also noted that travel distance to clinic was not perceived as a large stress factor. Taking these observations together, a healthcare model with a central location of providers well-versed in medical genetics may be considered if further data support our findings. The data from this study support a need for improving healthcare provider knowledge of genetics. Future studies exploring how these perceived stress factors are impacting families as well as different methods of educating providers are suggested by findings from the study, as well as studies querying the opinions of those who are unable to access genetics services.

Oral Ingestion and Intraventricular Injection of Curcumin Attenuates the Effort-Related Effects of the VMAT-2 Inhibitor Tetrabenazine: Implications for Motivational Symptoms of Depression.

Effort-related choice tasks are used for studying depressive motivational symptoms such as anergia/fatigue. These studies investigated the ability of the dietary supplement curcumin to reverse the low-effort bias induced by the monoamine storage blocker tetrabenazine. Tetrabenazine shifted effort-related choice in rats, decreasing high-effort lever pressing but increasing chow intake. The effects of tetrabenazine were reversed by oral ingestion of curcumin (80.0-160.0 mg/kg) and infusions of curcumin into the cerebral ventricles (2.0-8.0 µg). Curcumin attenuates the effort-related effects of tetrabenazine in this model via actions on the brain, suggesting that curcumin may be useful for treating human motivational symptoms.

First evidence of bryophyte diaspores in the plumage of transequatorial migrant birds.

Correlations between transequatorial migratory bird routes and bipolar biogeographic disjunctions in bryophytes suggest that disjunctions between northern and southern high latitude regions may result from bird-mediated dispersal; supporting evidence is, however, exclusively circumstantial. Birds disperse plant units (diaspores) internally via ingestion (endozoochory) or externally by the attachment of diaspores to the body (ectozoochory). Endozoochory is known to be the primary means of bird-mediated dispersal for seeds and invertebrates at local, regional, and continental scales. Data supporting the role of bird-mediated endozoochory or ectozoochory in the long distance dispersal of bryophytes remain sparse, however, despite the large number of bryophytes displaying bipolar disjunctions. To determine if transequatorial migrant shorebirds may play a role in the ectozoochory of bryophyte diaspores, we developed a method for screening feathers of wild birds. We provide the first evidence of microscopic bryophyte diaspores, as well as those from non-bryophyte lineages, embedded in the plumage of long distance transequatorial migrant birds captured in their arctic breeding grounds. The number of diaspores recovered suggests that entire migratory populations may be departing their northern breeding grounds laden with potentially viable plant parts and that they could thereby play significant roles in bipolar range expansions of lineages previously ignored in the migrant bird dispersal literature.