FLT3 stop mutation increases FLT3 ligand level and risk of autoimmune thyroid disease.

Autoimmune thyroid disease is the most common autoimmune disease and is highly heritable1. Here, by using a genome-wide association study of 30,234 cases and 725,172 controls from Iceland and the UK Biobank, we find 99 sequence variants at 93 loci, of which 84 variants are previously unreported2-7. A low-frequency (1.36%) intronic variant in FLT3 (rs76428106-C) has the largest effect on risk of autoimmune thyroid disease (odds ratio (OR) = 1.46, P = 2.37 × 10-24). rs76428106-C is also associated with systemic lupus erythematosus (OR = 1.90, P = 6.46 × 10-4), rheumatoid factor and/or anti-CCP-positive rheumatoid arthritis (OR = 1.41, P = 4.31 × 10-4) and coeliac disease (OR = 1.62, P = 1.20 × 10-4). FLT3 encodes fms-related tyrosine kinase 3, a receptor that regulates haematopoietic progenitor and dendritic cells. RNA sequencing revealed that rs76428106-C generates a cryptic splice site, which introduces a stop codon in 30% of transcripts that are predicted to encode a truncated protein, which lacks its tyrosine kinase domains. Each copy of rs76428106-C doubles the plasma levels of the FTL3 ligand. Activating somatic mutations in FLT3 are associated with acute myeloid leukaemia8 with a poor prognosis and rs76428106-C also predisposes individuals to acute myeloid leukaemia (OR = 1.90, P = 5.40 × 10-3). Thus, a predicted loss-of-function germline mutation in FLT3 causes a reduction in full-length FLT3, with a compensatory increase in the levels of its ligand and an increased disease risk, similar to that of a gain-of-function mutation.

Warfarin Is Associated With Higher Rates of Upper But Not Lower Gastrointestinal Bleeding Compared with Direct Oral Anticoagulants: A Population-Based Propensity-Weighted Cohort Study.

BACKGROUND AND AIMS: While overall gastrointestinal bleeding (GIB) rates have been extensively compared between warfarin and direct oral anticoagulants (DOACs), it is still unclear whether upper and lower GIB rates differ between these types of drugs. This study aimed to compare upper and lower GIB rates between warfarin and DOACs in a nationwide cohort. METHODS: Data on all patients in Iceland who received a prescription for oral anticoagulation from 2014 to 2019 were collected and their personal identification numbers linked to the electronic medical record system of the National University Hospital of Iceland and the 4 regional hospitals in Iceland. Inverse probability weighting was used to yield balanced study groups and rates of overall, major, upper, and lower GIB were compared using Cox regression. All GIB events were manually confirmed by chart review. RESULTS: Warfarin was associated with higher rates of upper GIB (1.7 events per 100 person-years vs 0.8 events per 100 person-years; hazard ratio [HR], 2.12; 95% confidence interval [CI], 1.26-3.59) but similar rates of lower GIB compared with DOACs. Specifically, warfarin was associated with higher rates of upper GIB compared with apixaban (HR, 2.63; 95% CI, 1.35-5.13), dabigatran (5.47; 95% CI, 1.87-16.05), and rivaroxaban (HR, 1.74; 95% CI, 1.00-3.05). Warfarin was associated with higher rates of major GIB compared with apixaban (2.3 events per 100 person-years vs 1.5 events per 100 person-years; HR, 1.79; 95% CI, 1.06-3.05), but otherwise overall and major GIB rates were similar in warfarin and DOAC users. CONCLUSIONS: Warfarin was associated with higher rates of upper but not overall or lower GIB compared with DOACs. Warfarin was associated with higher rates of major GIB compared with apixaban.

Ignoring instead of chasing after coagulation factor VII during warfarin management: an interrupted time series study.

During warfarin management, variability in prothrombin time-based international normalized ratio (PT-INR) is caused, in part, by clinically inconsequential fluctuations in factor VII (FVII). The new factor II and X (Fiix)-prothrombin time (Fiix-PT) and Fiix-normalized ratio (Fiix-NR), unlike PT-INR, are only affected by reduced FII and FX. We assessed the incidence of thromboembolism (TE) and major bleeding (MB) in all 2667 patients on maintenance-phase warfarin managed at our anticoagulation management service during 30 months; 12 months prior to and 18 months after replacing PT-INR monitoring with Fiix-NR monitoring. Months 13 to 18 were predefined as transitional months. Using 2-segmented regression, a breakpoint in the monthly incidence of TE became evident 6 months after test replacement, that was followed by a 56% reduction in incidence (from 2.82% to 1.23% per patient-year; P = .019). Three-segmented regression did not find any significant trend in TE incidence (slope, +0.03) prior to test replacement; however, during months 13 to 18 and 19 to 30, the incidence of TE decreased gradually (slope, -0.12; R2 = 0.20; P = .007). The incidence of MB (2.79% per patient-year) did not differ. Incidence comparison during the 12-month Fiix and PT periods confirmed a statistically significant reduction (55-62%) in TE. Fiix monitoring reduced testing, dose adjustments, and normalized ratio variability and prolonged testing intervals and time in range. We conclude that ignoring FVII during Fiix-NR monitoring in real-world practice stabilizes the anticoagulant effect of warfarin and associates with a major reduction in TEs without increasing bleeding.

Warfarin is associated with higher rates of epistaxis compared to direct oral anticoagulants: A nationwide propensity score-weighted study.

BACKGROUND: Although epistaxis is one of the most common side effects of oral anticoagulation, it is unclear whether epistaxis rates vary between different oral anticoagulants (OAC). OBJECTIVE: To compare rates of clinically relevant epistaxis between OAC. METHODS: Epistaxis event rates were compared between new users of apixaban, dabigatran, rivaroxaban, and warfarin in a nationwide population-based cohort study over a 5-year study period, 2014-2019. Data was collected from the Icelandic Medicine Registry and the five major hospitals in Iceland. Inverse probability weighting (IPW) was used to yield balanced baseline characteristics, and epistaxis rates were compared using Kaplan-Meier survival estimates and Cox regression. RESULTS: During the study period, 2098 patients received apixaban, 474 dabigatran, 3106 rivaroxaban, and 1403 warfarin. In total, 93 patients presented with clinically relevant epistaxis, including 11 (12%) major epistaxis events and one fatal epistaxis episode. Furthermore, seven patients (9%) with non-major epistaxis later presented with major bleeding during the follow-up period. Warfarin use was associated with higher rates of epistaxis compared to apixaban (2.2 events per 100-person years (events/100-py) vs. 0.6 events/100-py, hazard ratio [HR] 4.22, 95% confidence interval [CI] 2.08-8.59, p < 0.001), rivaroxaban (2.2 events/100-py vs. 1.0 events/100-py, HR 2.26, 95% CI 1.28-4.01, p = 0.005), and dabigatran (2.2 events/100-py vs. no events, HR n/a, p < 0.001). CONCLUSION: Warfarin treatment was associated with higher rates of clinically relevant epistaxis compared to direct oral anticoagulants.

Platelet function testing: Current practice among clinical centres in Northern Europe.

INTRODUCTION: Platelet function tests are used to screen and diagnose patients with possible inherited platelet function defects (IPFD). Some acquired platelet dysfunction may be caused by certain drugs or comorbidities, which need to be excluded before testing. AIMS: To identify current practice among centres performing platelet function tests in Northern Europe. METHODS: A total of 14 clinical centres from Sweden (six), Finland (two), Denmark (two), Norway (one), Estonia (two) and Iceland (one) completed the survey questionnaire, the population capture area of about 29.5 million. RESULTS: Six of the 14 (42.8%) centres providing platelet function assessment represent comprehensive treatment centres (EUHANET status). A Bleeding score (BS) or ISTH bleeding assessment tool (ISTH BAT score) is evaluated in 11/14 (78.6%) centres and family history in all. Five/14 centres (35.7%) use structured preanalytical patient instructions, and 10/14 (71.4%) recorded questionnaire on the preassessment of avoidance of any drugs or natural products affecting platelet functions. Preliminary investigations of screening tests of coagulation are performed in 10/14 (71.4%), while in 4/14 (28.6%), the diagnostic work-up of IPFD and von Willebrand disease (VWD) is performed simultaneously. The work-up of IPFD includes peripheral blood smear in 10/14 (71.4%), platelet aggregometry in all, flow cytometry in 10/14 (71.4%) and Platelet Function Analysis (PFA) in 3/11 (28.6%). Molecular genetic diagnosis is available in 7/14 (50%) centres. CONCLUSIONS: The considerable variability in the current practice illustrates the need for harmonization between the Northern European centres according to the international registers (i.e. EUHASS) and IPFD guidelines (ISTH, EHA).

Rivaroxaban Is Associated With Higher Rates of Gastrointestinal Bleeding Than Other Direct Oral Anticoagulants : A Nationwide Propensity Score-Weighted Study.

BACKGROUND: Gastrointestinal bleeding (GIB) rates for direct oral anticoagulants (DOACs) and warfarin have been extensively compared. However, population-based studies comparing GIB rates among different DOACs are limited. OBJECTIVE: To compare rates of GIB among apixaban, dabigatran, and rivaroxaban. DESIGN: Nationwide population-based cohort study. SETTING: Landspítali-The National University Hospital of Iceland and the 4 regional hospitals in Iceland. PATIENTS: New users of apixaban, dabigatran, and rivaroxaban from 2014 to 2019. MEASUREMENTS: Rates of GIB were compared using inverse probability weighting, Kaplan-Meier survival estimates, and Cox regression. RESULTS: In total, 2157 patients receiving apixaban, 494 patients receiving dabigatran, and 3217 patients receiving rivaroxaban were compared. For all patients, rivaroxaban had higher overall rates of GIB (3.2 vs. 2.5 events per 100 person-years; hazard ratio [HR], 1.42 [95% CI, 1.04 to 1.93]) and major GIB (1.9 vs. 1.4 events per 100 person-years; HR, 1.50 [CI, 1.00 to 2.24]) compared with apixaban. Rivaroxaban also had higher GIB rates than dabigatran, with similar point estimates, although the CIs were wider and included the possibility of a null effect. When only patients with atrial fibrillation were included, rivaroxaban was associated with higher rates of overall GIB than apixaban (HR, 1.40 [CI, 1.01 to 1.94]) or dabigatran (HR, 2.04 [CI, 1.17 to 3.55]). Dabigatran was associated with lower rates of upper GIB than rivaroxaban in both analyses. LIMITATIONS: Unmeasured confounding and small subgroup analyses. CONCLUSION: Rivaroxaban was associated with higher GIB rates than apixaban and dabigatran regardless of treatment indication. PRIMARY FUNDING SOURCE: Icelandic Centre for Research and Landspítali-The National University Hospital of Iceland.

Sequence variants associating with urinary biomarkers.

Urine dipstick tests are widely used in routine medical care to diagnose kidney and urinary tract and metabolic diseases. Several environmental factors are known to affect the test results, whereas the effects of genetic diversity are largely unknown. We tested 32.5 million sequence variants for association with urinary biomarkers in a set of 150 274 Icelanders with urine dipstick measurements. We detected 20 association signals, of which 14 are novel, associating with at least one of five clinical entities defined by the urine dipstick: glucosuria, ketonuria, proteinuria, hematuria and urine pH. These include three independent glucosuria variants at SLC5A2, the gene encoding the sodium-dependent glucose transporter (SGLT2), a protein targeted pharmacologically to increase urinary glucose excretion in the treatment of diabetes. Two variants associating with proteinuria are in LRP2 and CUBN, encoding the co-transporters megalin and cubilin, respectively, that mediate proximal tubule protein uptake. One of the hematuria-associated variants is a rare, previously unreported 2.5 kb exonic deletion in COL4A3. Of the four signals associated with urine pH, we note that the pH-increasing alleles of two variants (POU2AF1, WDR72) associate significantly with increased risk of kidney stones. Our results reveal that genetic factors affect variability in urinary biomarkers, in both a disease dependent and independent context.

A comparison of platelet quality between platelets from healthy donors and hereditary hemochromatosis donors over seven-day storage.

BACKGROUND: Therapeutic phlebotomy is the standard treatment of hereditary hemochromatosis (HH), the most common genetic disease in people of Northern European descent. Red cell concentrates from HH donors have been reported safe for transfusion, but little data is available on the storage properties of platelet concentrates from HH donors. STUDY DESIGN AND METHODS: Whole blood was collected from 10 healthy individuals and 10 newly diagnosed HH patients with elevated serum ferritin. Platelet-rich plasma (PRP) was prepared and split into four 20-mL units. Platelet quality tests were performed on days 0, 1, 3, 5, and 7 of storage, including platelet aggregation (ADP, arachidonic acid, collagen, and epinephrine agonists), blood gas analysis, flow cytometry (CD41, CD42b, and CD62P expression), and ELISA (sCD40L and sCD62p in supernatant). RESULTS: Mean serum ferritin levels were higher in HH patients than in controls (847.5 vs 45.8 ng/mL, P < .001). Overall, no difference in quality test results was observed between the two study groups over 7-day storage (P > .05), including blood gas analysis, platelet aggregation, and expression of surface (CD62p and CD42b) and secreted (sCD62P and sCD40L) activation markers. Expected alterations in metabolic (CO2 and glucose decrease, O2 and lactate increase, P < .001) and platelet activation markers (CD42b decrease, CD62P increase, P < .05) over time were observed in both groups. CONCLUSION: Although these findings indicate that platelets of individuals with HH are comparable to platelets from healthy donors, more extensive studies are needed before definite conclusions can be drawn.

Replacement of traditional prothrombin time monitoring with the new Fiix prothrombin time increases the efficacy of warfarin without increasing bleeding. A review article.

The antithrombotic effect of vitamin K antagonists (VKA) depends on controlled lowering of the activity of factors (F) II and X whereas reductions in FVII and FIX play little role. PT-INR based monitoring, however, is highly influenced by FVII, which has the shortest half-life of vitamin K-dependent coagulation factors. Hence, variability in the anticoagulant effect of VKA may be partly secondary to an inherent flaw of the traditional monitoring test itself. The Fiix prothrombin time (Fiix-PT) is a novel test that is only sensitive to reductions in FII and FX and is intended to stabilize the VKA effect. Two clinical studies have now demonstrated that when warfarin is monitored with the Fiix-PT based normalized ratio (Fiix-NR) instead of PT-INR, anticoagulation is stabilized and less testing and fewer dose adjustments are needed. Furthermore, the relative risk of thromboembolism was reduced by 50-56% in these studies without an increase in major bleeding.

The need for an adapted initiation nomogram during Fiix prothrombin time monitoring of warfarin.

The new Fiix prothrombin time (Fiix-PT) and its derived Fiix-normalized ratio (Fiix-NR) is affected only by reductions in coagulation factors (F) II and X, the two factors responsible for the antithrombotic effect of vitamin K antagonists (VKA). Due to insensitivity to reductions in the short half-life FVII, the Fiix-NR rises later than standard PT-INR during warfarin initiation. To describe a warfarin initiation nomogram adapted for monitoring with Fiix-NR, anticoagulation development was assessed during use of standard PT-INR based initiation nomogram and after adapting the initiation nomogram for Fiix-NR monitoring. Normalized ratios were retrospectively assessed in consecutive warfarin naïve patients during their first 60 days of warfarin intake for one year prior to (PT-INR period) and for one year after replacing the PT-INR with the Fiix-NR (Fiix-NR period). The INR target was NR 2.0-3.0. We evaluated 160 patients monitored with PT-INR and dosed with the PT-nomogram, 57 monitored with Fiix-INR but dosed with PT-nomogram, and 163 Fiix-NR monitored patients dosed using a new Fiix nomogram. Mean PT-INR over 2.0 was reached on day 7 during the PT-period and remained around 2.5 thereafter. When the PT-nomogram continued in use during Fiix-monitoring significantly more patients became overanticoagulated during days 11-29. After the nomogram was modified to respond to rising Fiix-NR with larger initial dose reduction, the mean Fiix-NR reached over 2 on day 8-9 and remained around 2.5 thereafter. When warfarin is monitored with Fiix-NR, an adjusted dosing nomogram should be used during initiation to prevent early overanticoagulation.

Reduced anticoagulation variability in patients on warfarin monitored with Fiix-prothrombin time associates with reduced thromboembolism: The Fiix-trial.

Fiix-prothrombin time (Fiix-PT) differs from traditional PT in being affected by reduced factor (F) II or FX only. In the randomized controlled Fiix-trial, patients on warfarin monitored with Fiix-PT (Fiix-warfarin patients) had fewer thromboembolisms (TE), similar major bleeding (MB) and more stable anticoagulation than patients monitored with PT (PT-warfarin patients). In the current Fiix-trial report we analyzed how reduced anticoagulation variability during Fiix-PT monitoring was reflected in patients with TE or bleeding. Data from 1143 randomized patients was used. We analyzed the groups for anticoagulation intensity (time within target range; TTR), international normalized ratio (INR) variability (variance growth rate B1; VGR) and dose adjustment frequency. We assessed how these parameters associated with clinically relevant vascular events (CRVE), ie TE or MB or clinically relevant non-MB. TTR was highest in Fiix-warfarin patients without CRVE (median 82%;IQR 72-91) and lowest in PT-warfarin patients with TE (62%;56-81). VGR was lowest in Fiix-warfarin patients without CRVE (median VGR B1 0.17; 95% CI 0.08-0.38) and with TE (0.20;0.07-0.26) and highest in PT-warfarin patients with TE (0.50;0.27-0.90) or MB (0.59;0.07-1.36). The mean annual dose adjustment frequency was lowest in Fiix-warfarin patients with TE (mean 5.4;95% CI 3.9-7.3) and without CRVE (mean 6.0; 5.8-6.2) and highest in PT-warfarin patients with TE (14.2;12.2-16.3). Frequent dose changes predicted MB in both study arms. Compared to patients monitored with PT, high anticoagulation stability in Fiix-warfarin patients coincided with their low TE rate. Those with bleeding had high variability irrespective of monitoring method. Thus, although further improvements are needed to reduce bleeding, stabilization of anticoagulation by Fiix-PT monitoring associates with reduced TE.

Clinical phenotype in heterozygote and biallelic Bernard-Soulier syndrome--a case control study.

Bernard-Soulier syndrome (BSS) is a rare severe autosomal recessive bleeding disorder. To date heterozygous carriers of BSS mutations have not been shown to have bleeding symptoms. We assessed bleeding using a semi-quantitative questionnaire, platelet parameters, PFA-100 closure times, ristocetin response, GP Ib/IX expression and VWF antigen in 14 BSS patients, 30 heterozygote carriers for related mutations and 29 controls. Eight mutations in GP1BA, GP1BB or GP9 were identified including four previously unknown pathogenic mutations. Subjects with BSS reported markedly more mucocutaneous bleeding than controls. Increased bleeding was also observed in heterozygotes. Compared to controls, patients with BSS had lower optical platelet counts (P < 0.001), CD61-platelet counts (P < 0.001) and higher mean platelet volume (17.7 vs. 7.8 fL, P < 0.001) and ristocetin response and closure times were unmeasurable. Heterozygotes had higher MPV (9.7 fL, P < 0.001) and lower platelet counts (P < 0.001) than controls but response to ristocetin and closure times were normal. The VWF was elevated in both BSS and in heterozygotes (P = 0.005). We conclude that heterozygotes for BSS mutations have lower platelet counts than controls and show a bleeding phenotype albeit much milder than in BSS. Both patients with BSS and heterozygote carriers of pathogenic mutations have raised VWF.

Complementary effect of fibrinogen and rFVIIa on clotting ex vivo in Bernard-Soulier syndrome and combined use during three deliveries.

Women with Bernard-Soulier syndrome (BSS) are considered to be at high risk of serious bleeding during childbirth. Due to the frequently occurring platelet transfusion refractoriness, alternative prophylactic therapy is required. Using rotational thromboelastometry, we evaluated the whole blood coagulation profile of a pregnant woman with BSS before and after spiking ex vivo with different concentrations of recombinant activated factor VII (rFVIIa) and fibrinogen. As experiments suggested improved clotting with clinically applicable concentrations of both agents in a complementary manner, the findings were confirmed on blood from a non-pregnant woman and three men suffering from BSS. During delivery, bleeding refractory to platelets occurred and immediately following delivery she received both rFVIIa and fibrinogen intravenously. Immediate cessation of bleeding occurred, and no postpartum hemorrhage was seen. Another woman with BSS later also received the same rFVIIa and fibrinogen treatment prophylactically after delivery without any postpartum bleeding. Eventually, the first woman during her second delivery received the same treatment again prophylactically without any bleeding. No side effects were observed during these three deliveries. Our observations suggest that rFVIIa combined with fibrinogen may provide a beneficial clinical hemostatic effect partly by separate but complementary mechanisms.

Comparison of medication adherence to different oral anticoagulants: population-based cohort study.

OBJECTIVE: Previous observational studies have yielded conflicting results on whether medication adherence differs between patients receiving warfarin and direct oral anticoagulants (DOACs). Importantly, no study has adequately accounted for warfarin dosing being continuously modified based on INR values while dosing of DOACs is fixed. We aimed to compare non-adherence between new users of apixaban, dabigatran, rivaroxaban and warfarin in a population-based cohort. METHODS: New users of apixaban, dabigatran, rivaroxaban and warfarin from 2014 to 2019 living in the Icelandic capital area were included. Non-adherence was defined as proportion of days covered below 80%. Inverse probability weighting was used to yield balanced study groups and non-adherence was compared using logistic regression. Factors associated with non-adherence were estimated using multivariable logistic regression. RESULTS: Overall, 1266 patients received apixaban, 247 dabigatran, 1566 rivaroxaban and 768 warfarin. The proportion of patients with non-adherence ranged from 10.5% to 16.7%. Dabigatran was associated with significantly higher odds of non-adherence compared with apixaban (OR 1.57, 95% CI 1.21 to 2.04, p<0.001), rivaroxaban (OR 1.45, 95% CI 1.12 to 1.89, p=0.005) and warfarin (OR 1.63, 95% CI 1.23 to 2.15, p<0.001). The odds of non-adherence were similar for apixaban, rivaroxaban and warfarin. Apart from the type of oral anticoagulants (OACs) used, female sex, hypertension, history of cerebrovascular accident and concomitant statin use were all independently associated with lower odds of non-adherence. CONCLUSION: Dabigatran was associated with higher odds of non-adherence compared with other OACs. Non-adherence was similar between apixaban, rivaroxaban and warfarin users. Female sex and higher comorbidity were associated with better medication adherence.

Comparison of the effectiveness and safety of direct oral anticoagulants: a nationwide propensity score-weighted study.

In the pivotal randomized controlled trials (RCTs) for patients with atrial fibrillation, direct oral anticoagulants (DOACs) had similar or even superior efficacy and safety compared with warfarin. However, RCTs comparing different DOACs are nonexistent and previous observational studies have yielded conflicting results. In this nationwide cohort study, rates of any stroke or systemic embolism (stroke/SE) and major bleeding were compared among new users of apixaban, dabigatran, and rivaroxaban with atrial fibrillation from 2014 to 2019. Inverse probability weighting was used to yield balanced study groups, and outcomes were compared using Cox regression. Stroke/SE rates were similar in patients receiving apixaban, dabigatran, and rivaroxaban. Dabigatran was associated with twofold higher rates of myocardial infarction (MI) than rivaroxaban (1.4 events/100 person-years (py) vs 0.7 events/100-py, hazard ratio [HR] 2.21, 95% confidence interval [CI], 1.00-4.90) and apixaban (1.4 events/100-py vs 0.7 events/100-py, HR 2.26, 95% CI, 0.90-5.67), although the second comparison included the possibility of a null effect. Rivaroxaban was associated with higher major bleeding rates compared with apixaban (2.9 events/100-py vs 1.8 events/100-py, HR 1.64, 95% CI, 1.13-2.37) and dabigatran (2.9 events/100-py vs 1.4 events/100-py, HR 2.18, 95% CI, 1.21-3.93). Specifically, rivaroxaban had higher rates of major gastrointestinal bleeding and other major bleeding than apixaban. In conclusion, although stroke/SE rates were similar for DOACs, rivaroxaban was associated with higher rates of major bleeding than other DOACs and lower rates of MI than dabigatran. These results may help guide oral anticoagulant selection, especially in patients at high risk of bleeding or MI.

Prevalence of smoldering multiple myeloma based on nationwide screening.

Smoldering multiple myeloma (SMM) is an asymptomatic precursor to multiple myeloma. Here we define the epidemiological characteristics of SMM in the general population in Iceland. The iStopMM study (ClinicalTrials.gov ID: NCT03327597 ) is a nationwide screening study for multiple myeloma precursors where all residents in Iceland 40 years or older were invited to participate. SMM was defined as 10-60% bone marrow plasma cells and/or monoclonal (M) protein concentration ≥3 g dl-1, in the absence of myeloma-defining events. Of the 80,759 who gave informed consent to participate, 75,422 (93%) were screened. The prevalence of SMM in the total population was 0.53% (95% confidence interval (CI) = 0.49-0.57%) in individuals 40 years or older. In men and women, the prevalence of SMM was 0.67% (95% CI = 0.62-0.73%) and 0.39% (95% CI = 0.35-0.43%), respectively; it increased with age in both sexes. For the 193 individuals with SMM, median age was 70 years (range 44-92 years) and 60% were males. The mean M protein concentration of individuals with SMM was 0.62 g dl-1 (range 0.01-3.5 g dl-1) and 73% had 11-20% bone marrow plasma cell infiltration. The high prevalence of SMM has implications for future treatment policies in multiple myeloma as the evidence supporting treatment initiation at the SMM stage is emerging.

Genome-wide meta-analysis identifies 93 risk loci and enables risk prediction equivalent to monogenic forms of venous thromboembolism.

We report a genome-wide association study of venous thromboembolism (VTE) incorporating 81,190 cases and 1,419,671 controls sampled from six cohorts. We identify 93 risk loci, of which 62 are previously unreported. Many of the identified risk loci are at genes encoding proteins with functions converging on the coagulation cascade or platelet function. A VTE polygenic risk score (PRS) enabled effective identification of both high- and low-risk individuals. Individuals within the top 0.1% of PRS distribution had a VTE risk similar to homozygous or compound heterozygous carriers of the variants G20210A (c.*97 G > A) in F2 and p.R534Q in F5. We also document that F2 and F5 mutation carriers in the bottom 10% of the PRS distribution had a risk similar to that of the general population. We further show that PRS improved individual risk prediction beyond that of genetic and clinical risk factors. We investigated the extent to which venous and arterial thrombosis share clinical risk factors using Mendelian randomization, finding that some risk factors for arterial thrombosis were directionally concordant with VTE risk (for example, body mass index and smoking) whereas others were discordant (for example, systolic blood pressure and triglyceride levels).

Sequence variant affects GCSAML splicing, mast cell specific proteins, and risk of urticaria.

Urticaria is a skin disorder characterized by outbreaks of raised pruritic wheals. In order to identify sequence variants associated with urticaria, we performed a meta-analysis of genome-wide association studies for urticaria with a total of 40,694 cases and 1,230,001 controls from Iceland, the UK, Finland, and Japan. We also performed transcriptome- and proteome-wide analyses in Iceland and the UK. We found nine sequence variants at nine loci associating with urticaria. The variants are at genes participating in type 2 immune responses and/or mast cell biology (CBLB, FCER1A, GCSAML, STAT6, TPSD1, ZFPM1), the innate immunity (C4), and NF-κB signaling. The most significant association was observed for the splice-donor variant rs56043070[A] (hg38: chr1:247556467) in GCSAML (MAF = 6.6%, OR = 1.24 (95%CI: 1.20-1.28), P-value = 3.6 × 10-44). We assessed the effects of the variants on transcripts, and levels of proteins relevant to urticaria pathophysiology. Our results emphasize the role of type 2 immune response and mast cell activation in the pathogenesis of urticaria. Our findings may point to an IgE-independent urticaria pathway that could help address unmet clinical need.

Genetic architecture of band neutrophil fraction in Iceland.

The characteristic lobulated nuclear morphology of granulocytes is partially determined by composition of nuclear envelope proteins. Abnormal nuclear morphology is primarily observed as an increased number of hypolobulated immature neutrophils, called band cells, during infection or in rare envelopathies like Pelger-Huët anomaly. To search for sequence variants affecting nuclear morphology of granulocytes, we performed a genome-wide association study using band neutrophil fraction from 88,101 Icelanders. We describe 13 sequence variants affecting band neutrophil fraction at nine loci. Five of the variants are at the Lamin B receptor (LBR) locus, encoding an inner nuclear membrane protein. Mutations in LBR are linked to Pelger-Huët anomaly. In addition, we identify cosegregation of a rare stop-gain sequence variant in LBR and Pelger Huët anomaly in an Icelandic eight generation pedigree, initially reported in 1963. Two of the other loci include genes which, like LBR, play a role in the nuclear membrane function and integrity. These GWAS results highlight the role proteins of the inner nuclear membrane have as important for neutrophil nuclear morphology.

Nordic Haemophilia Council's practical guidelines on diagnosis and management of von Willebrand disease.

Von Willebrand disease (VWD) is the most common inherited bleeding disorder characterized by spontaneous or tissue injury-related, mostly mucocutaneous, bleeding events. VWD affects both males and females and is caused by quantitative or qualitative deficiency of Von Willebrand factor. The diagnostic procedure is complicated because VWD is highly heterogeneous, and differential diagnosis from platelet disorders may be challenging. Moreover, these defects may even coexist, impacting the bleeding phenotype. Mild and moderate VWD can be difficult to distinguish from the normal population, and VWD subtyping may also be problematic. This article summarizes the guidelines of the Nordic Haemophilia Council (NHC), which are intended to serve as a practical tool and provide the standards for diagnosing and treating VWD patients. The complete Nordic Guidelines on VWD are available at the NHC Web site (http://nordhemophilia.org).