Vitamin K-dependent carboxylation regulates Ca2+ flux and adaptation to metabolic stress in ß cells.

Vitamin K is a micronutrient necessary for γ-carboxylation of glutamic acids. This post-translational modification occurs in the endoplasmic reticulum (ER) and affects secreted proteins. Recent clinical studies implicate vitamin K in the pathophysiology of diabetes, but the underlying molecular mechanism remains unknown. Here, we show that mouse ß cells lacking γ-carboxylation fail to adapt their insulin secretion in the context of age-related insulin resistance or diet-induced ß cell stress. In human islets, γ-carboxylase expression positively correlates with improved insulin secretion in response to glucose. We identify endoplasmic reticulum Gla protein (ERGP) as a γ-carboxylated ER-resident Ca2+-binding protein expressed in ß cells. Mechanistically, γ-carboxylation of ERGP protects cells against Ca2+ overfilling by diminishing STIM1 and Orai1 interaction and restraining store-operated Ca2+ entry. These results reveal a critical role of vitamin K-dependent carboxylation in regulation of Ca2+ flux in ß cells and in their capacity to adapt to metabolic stress.

How do members of the public expect to use variants of uncertain significance in their health care? A population-based survey.

PURPOSE: Genomic sequencing can generate complex results, including variants of uncertain significance (VUS). In general, VUS should not inform clinical decision-making. This study aimed to assess the public's expected management of VUS. METHODS: An online, hypothetical survey was conducted among members of the Canadian public preceded by an educational video. Participants were randomized to 1 of 2 arms, VUS or pathogenic variant in a colorectal cancer gene, and asked which types of health services they expected to use for this result. Expected health service use was compared between randomization arms, and associations between participants' sociodemographic characteristics, attitudes, and medical history were explored. RESULTS: Among 1003 respondents (completion rate 60%), more participants expected to use each type of health service for a pathogenic variant than for a VUS. However, a considerable proportion of participants expected to request monitoring (73.4%) and consult health care providers (60.9%) for a VUS. There was evidence to support associations between expectation to use health services for a VUS with family history of genetic disease, family history of cancer, education, and attitudes toward health care and technology. CONCLUSION: Many participants expected to use health services for a VUS in a colorectal cancer predisposition gene, suggesting a potential disconnect between patients' expectations for VUS management and guideline-recommended care.

Characterization of variant reclassification and patient re-contact in a cancer genetics clinic.

Expanded genetic testing guidelines for hereditary cancers, increased utilization of large multigene panels, and improved methods for reclassifying variants have led to a greater need to understand how variant reclassification and patient re-contact are managed. This study aimed to describe the process of variant reclassification and subsequent patient re-contact at a comprehensive cancer genetic counseling service in a large metropolitan medical center with several statewide satellite locations. A retrospective chart review was performed to identify reclassified variants between 1/1/1997 and 12/1/2020. In total, 8.4% (211/2503) of variants were reclassified over the 24-year period, which includes multiple cases involving the same unique variant. Several variants underwent more than one reclassification, resulting in 232 total reclassifications among 194 individuals. Nearly all reclassifications were prompted by the laboratory (99.1%; 230/232) rather than the genetics clinic staff. Overall, 10.3% (24/232) of all reclassifications were upgrades, but only 9.1% (21/232) led to a change in management recommendations. The median time for variant reclassification was 1.7 years (interquartile range [IQR] = 0.8-3.2 years). There was no statistically significant difference in the time to reclassification for White patients (median = 1.6 years; IQR = 0.8-2.8 years) compared to non-White patients (median = 2.0 years; IQR = 0.9-3.7 years; Mann-Whitney U = 4,764.0, p = 0.066). Patient re-contact was attempted for 97.4% (226/232) of variants and was always performed by a genetic counselor, most often through a mailed letter (85.8%, 194/226). Specifically for reclassifications that led to a change in management recommendations, re-contact was always attempted, most often through combined telephone and mailed letter (95.2%; 20/21). Overall, the median time from reclassification to attempted patient re-contact was 13 days (range: 0-589 days). The characterization of this clinic's reclassification and re-contact procedures can serve as an example for other genetics clinics trying to incorporate re-contact into their workflow.

Patient and public preferences for being recontacted with updated genomic results: a mixed methods study.

Variants of uncertain significance (VUS) are frequently reclassified but recontacting patients with updated results poses significant resource challenges. We aimed to characterize public and patient preferences for being recontacted with updated results. A discrete choice experiment (DCE) was administered to representative samples of the Canadian public and cancer patients. DCE attributes were uncertainty, cost, recontact modality, choice of results, and actionability. DCE data were analyzed using a mixed logit model and by calculating willingness to pay (WTP) for types of recontact. Qualitative interviews exploring recontact preferences were analyzed thematically. DCE response rate was 60% (n = 1003, 50% cancer patient participants). 31 participants were interviewed (11 cancer patients). Interviews revealed that participants expected to be recontacted. Quantitatively, preferences for how to be recontacted varied based on certainty of results. For certain results, WTP was highest for being recontacted by a doctor with updates ($1075, 95% CI: $845, $1305) and for contacting a doctor to request updates ($1038, 95% CI: $820, $1256). For VUS results, WTP was highest for an online database ($1735, 95% CI: $1224, $2247) and for contacting a doctor ($1705, 95% CI: $1102, $2307). Qualitative data revealed that preferences for provider-mediated recontact were influenced by trust in healthcare providers. Preferences for a database were influenced by lack of trust in providers and desire for control. Patients and public participants support an online database (e.g. patient portal) to recontact for VUS, improving feasibility, and provider-mediated recontact for certain results, consistent with usual care.

Effectiveness of the Genomics ADvISER decision aid for the selection of secondary findings from genomic sequencing: a randomized clinical trial.

PURPOSE: To evaluate the effectiveness of the Genomics ADvISER (www.genomicsadviser.com) decision aid (DA) for selection of secondary findings (SF), compared with genetic counseling alone. METHODS: A randomized controlled trial (RCT) was conducted to evaluate whether the Genomics ADvISER is superior to genetic counseling when hypothetically selecting SF. Participants were randomized to use the DA followed by discussion with a genetic counselor, or to genetic counseling alone. Surveys were administered at baseline and post-intervention. Primary outcome was decisional conflict. Secondary outcomes were knowledge, preparation for, and satisfaction with decision-making, anxiety, and length of counseling session. RESULTS: Participants (n = 133) were predominantly White/European (74%), female (90%), and ≥50 years old (60%). Decisional conflict (mean difference 0.05; P = 0.60), preparation for decision-making (0.17; P = 0.95), satisfaction with decision (-2.18; P = 0.06), anxiety (0.72; P = 0.56), and knowledge of sequencing limitations (0.14; P = 0.70) did not significantly differ between groups. However, intervention participants had significantly higher knowledge of SF (0.39; P < 0.001) and sequencing benefits (0.97; P = 0.01), and significantly shorter counseling time (24.40 minutes less; P < 0.001) CONCLUSIONS: The Genomics ADvISER did not decrease decisional conflict but reduced counseling time and improved knowledge. This decision aid could serve as an educational tool, reducing in-clinic time and potentially health care costs.

Physiological and genomic evidence that selection on the transcription factor Epas1 has altered cardiovascular function in high-altitude deer mice.

Evolutionary adaptation to extreme environments often requires coordinated changes in multiple intersecting physiological pathways, but how such multi-trait adaptation occurs remains unresolved. Transcription factors, which regulate the expression of many genes and can simultaneously alter multiple phenotypes, may be common targets of selection if the benefits of induced changes outweigh the costs of negative pleiotropic effects. We combined complimentary population genetic analyses and physiological experiments in North American deer mice (Peromyscus maniculatus) to examine links between genetic variation in transcription factors that coordinate physiological responses to hypoxia (hypoxia-inducible factors, HIFs) and multiple physiological traits that potentially contribute to high-altitude adaptation. First, we sequenced the exomes of 100 mice sampled from different elevations and discovered that several SNPs in the gene Epas1, which encodes the oxygen sensitive subunit of HIF-2α, exhibited extreme allele frequency differences between highland and lowland populations. Broader geographic sampling confirmed that Epas1 genotype varied predictably with altitude throughout the western US. We then discovered that Epas1 genotype influences heart rate in hypoxia, and the transcriptomic responses to hypoxia (including HIF targets and genes involved in catecholamine signaling) in the heart and adrenal gland. Finally, we used a demographically-informed selection scan to show that Epas1 variants have experienced a history of spatially varying selection, suggesting that differences in cardiovascular function and gene regulation contribute to high-altitude adaptation. Our results suggest a mechanism by which Epas1 may aid long-term survival of high-altitude deer mice and provide general insights into the role that highly pleiotropic transcription factors may play in the process of environmental adaptation.