Pathogenic variants affecting the TB5 domain of the fibrillin-1 protein: not only in geleophysic/acromicric dysplasias but also in Marfan syndrome

BACKGROUND

Marfan syndrome (MFS) is a multisystem disease with a unique combination of skeletal, cardiovascular and ocular features. Geleophysic/acromicric dysplasias (GPHYSD/ACMICD), characterised by short stature and extremities, are described as 'the mirror image' of MFS. The numerous FBN1 pathogenic variants identified in MFS are located all along the gene and lead to the same final pathogenic sequence. Conversely, in GPHYSD/ACMICD, the 28 known heterozygous FBN1 pathogenic variants all affect exons 41-42 encoding TGFβ-binding protein-like domain 5 (TB5).

METHODS

Since 1996, more than 5000 consecutive probands have been referred nationwide to our laboratory for molecular diagnosis of suspected MFS.

RESULTS

We identified five MFS probands carrying distinct heterozygous pathogenic in-frame variants affecting the TB5 domain of FBN1. The clinical data showed that the probands displayed a classical form of MFS. Strikingly, one missense variant affects an amino acid that was previously involved in GPHYSD.

CONCLUSION

Surprisingly, pathogenic variants in the TB5 domain of FBN1 can lead to two opposite phenotypes: GPHYSD/ACMICD and MFS, suggesting the existence of different pathogenic sequences with the involvement of tissue specificity. Further functional studies are ongoing to determine the precise role of this domain in the physiopathology of each disease.

Establishing a multi-specialty consensus in the clinical need for hypercholesterolemia management and its implication for patients access to innovative therapies

BACKGROUND

Increased level of blood LDL-C has a causal and cumulative effect on advancing atherosclerotic cardiovascular diseases (ASCVD). European guidelines for treating high LDL-C levels have been recently updated. However, in France, several challenges (e.g., physician and patient awareness, healthcare management) limit the application of management guidelines. The aim of this study was to understand the current opinions and perceived unmet clinical needs in recognising and managing hypercholesterolemia as an ASCVD risk factor, and to explore consensus around factors that support the effective management of elevated LDL-C.

METHODS

An expert group of cardiologists, endocrinologists, biology/genetics researchers, and a health technology assessments expert, from France was convened. The current management of hypercholesterolemia and barriers to achieving LDL-C goals in France were discussed and 44 statements were developed. Wider consensus was assessed by sending the statements as a 4-point Likert Scale questionnaire to cardiologists and endocrinologists across France. The consensus threshold was defined as ≥75%.

RESULTS

A total of 101 responses were received. Consensus was very high (>90%) in 25 (57%) statements, high (≥75%) in 18 (41%) statements and was not achieved (<75%) only in 1 (2%) of statements. Overall, 43 statements achieved consensus.

CONCLUSIONS

Based on consensus levels, key recommendations for improving current guidelines and approaches to care have been developed. Implementation of these recommendations will lead to better concordance with international treatment guidelines and increase levels of education for healthcare practitioners and patients. In turn, this will improve the available treatment pathways for cardiovascular diseases, potentially creating improved patient outcomes in the future.

Comparative Effectiveness of Bivalent (Original/Omicron BA.4/BA.5) COVID-19 Vaccines in Adults

The emergence of Omicron variants coincided with declining vaccine-induced protection against SARS-CoV-2. Two bivalent mRNA vaccines, mRNA-1273.222 (Moderna) and BNT162b2 Bivalent (Pfizer-BioNTech), were developed to provide greater protection against the predominate circulating variants by including mRNA that encodes both the ancestral (original) strain and BA.4/BA.5. We estimated their relative vaccine effectiveness (rVE) in preventing COVID-19-related outcomes in the US using a nationwide dataset linking primary care electronic health records and pharmacy/medical claims data. The study population (aged ≥18 years) received either vaccine between 31 August 2022 and 28 February 2023. We used propensity score weighting to adjust for baseline differences between groups. We estimated the rVE against COVID-19-related hospitalizations (primary outcome) and outpatient visits (secondary) for 1,034,538 mRNA-1273.222 and 1,670,666 BNT162b2 Bivalent vaccine recipients, with an adjusted rVE of 9.8% (95% confidence interval: 2.6-16.4%) and 5.1% (95% CI: 3.2-6.9%), respectively, for mRNA-1273.222 versus BNT162b2 Bivalent. The incremental relative effectiveness was greater among adults ≥ 65; the rVE against COVID-19-related hospitalizations and outpatient visits in these patients was 13.5% (95% CI: 5.5-20.8%) and 10.7% (8.2-13.1%), respectively. Overall, we found greater effectiveness of mRNA-1273.222 compared with the BNT162b2 Bivalent vaccine in preventing COVID-19-related hospitalizations and outpatient visits, with increased benefits in older adults.

Liver disease in germline mutations of telomere-related genes: Prevalence, clinical, radiological, pathological features, outcome, and risk factors

BACKGROUND AND AIM

Germline mutations of telomere-related genes (TRG) induce multiorgan dysfunction, and liver-specific manifestations have not been clearly outlined. We aimed to describe TRG mutations-associated liver diseases.

APPROACH AND RESULTS

Retrospective multicenter analysis of liver disease (transaminases > 30 IU/L and/or abnormal liver imaging) in patients with TRG mutations. Main measurements were characteristics, outcomes, and risk factors of liver disease in a TRG mutations cohort. The prevalence of liver disease was compared to a community-based control group (n = 1190) stratified for age and matched 1:3 for known risk factors of liver disease. Among 132 patients with TRG mutations, 95 (72%) had liver disease, with associated lung, blood, skin, rheumatological, and ophthalmological TRG diseases in 82%, 77%, 55%, 39%, and 30% of cases, respectively. Liver biopsy was performed in 52/95 patients, identifying porto-sinusoidal vascular disease in 48% and advanced fibrosis/cirrhosis in 15%. After a follow-up of 21 months (12-54), ascites, hepato-pulmonary syndrome, variceal bleeding, and HCC occurred in 14%, 13%, 13%, and 2% of cases, respectively. Five-year liver transplantation-free survival was 69%. A FIB-4 score ≥ 3·25 and ≥1 risk factor for cirrhosis were associated with poor liver transplantation-free survival. Liver disease was more frequent in patients with TRG mutations than in the paired control group [80/396, (20%)], OR 12.9 (CI 95%: 7.8-21.3, p < 0.001).

CONCLUSIONS

TRG mutations significantly increase the risk of developing liver disease. Although symptoms may be mild, they may be associated with severe disease. Porto-sinusoidal vascular disease and cirrhosis were the most frequent lesions, suggesting that the mechanism of action is multifactorial.

Precision medicine in rare diseases: What is next?

Molecular diagnostics is a cornerstone of modern precision medicine, broadly understood as tailoring an individual's treatment, follow-up, and care based on molecular data. In rare diseases (RDs), molecular diagnoses reveal valuable information about the cause of symptoms, disease progression, familial risk, and in certain cases, unlock access to targeted therapies. Due to decreasing DNA sequencing costs, genome sequencing (GS) is emerging as the primary method for precision diagnostics in RDs. Several ongoing European initiatives for precision medicine have chosen GS as their method of choice. Recent research supports the role for GS as first-line genetic investigation in individuals with suspected RD, due to its improved diagnostic yield compared to other methods. Moreover, GS can detect a broad range of genetic aberrations including those in noncoding regions, producing comprehensive data that can be periodically reanalyzed for years to come when further evidence emerges. Indeed, targeted drug development and repurposing of medicines can be accelerated as more individuals with RDs receive a molecular diagnosis. Multidisciplinary teams in which clinical specialists collaborate with geneticists, genomics education of professionals and the public, and dialogue with patient advocacy groups are essential elements for the integration of precision medicine into clinical practice worldwide. It is also paramount that large research projects share genetic data and leverage novel technologies to fully diagnose individuals with RDs. In conclusion, GS increases diagnostic yields and is a crucial step toward precision medicine for RDs. Its clinical implementation will enable better patient management, unlock targeted therapies, and guide the development of innovative treatments.

Relative Effectiveness of BNT162b2, mRNA-1273, and Ad26.COV2.S Vaccines and Homologous Boosting in Preventing COVID-19 in Adults in the US

Background

Few head-to-head comparisons have been performed on the real-world effectiveness of coronavirus disease 2019 (COVID-19) booster vaccines. We evaluated the relative effectiveness (rVE) of a primary series of mRNA-1273 vs BNT162b2 and Ad26.COV2.S and a homologous mRNA booster against any medically attended, outpatient, and hospitalized COVID-19.

Methods

A data set linking primary care electronic medical records with medical claims data was used for this retrospective cohort study of US patients age ≥18 years vaccinated with a primary series between February and October 2021 (Part 1) and a homologous mRNA booster between October 2021 and January 2022 (Part 2). Adjusted hazard ratios (HRs) were derived from 1:1 matching adjusted across potential covariates. rVE was (1 - HR_adjusted) × 100. Additional analysis was performed across regions and age groups.

Results

Following adjustment, Part 1 rVE for mRNA-1273 vs BNT162b2 was 23% (95% CI, 22%-25%), 23% (95% CI, 22%-25%), and 19% (95% CI, 14%-24%), while the rVE for mRNA-1273 vs Ad26.COV2.S was 50% (95% CI, 48%-51%), 50% (95% CI, 48%-52%), and 57% (95% CI, 53%-61%) against any medically attended, outpatient, and hospitalized COVID-19, respectively. The adjusted rVE in Part 2 for mRNA-1273 vs BNT162b2 was 14% (95% CI, 10%-18%), 13% (95% CI, 8%-17%), and 19% (95% CI, 1%-34%) against any medically attended, outpatient, and hospitalized COVID-19, respectively. rVE against medically attended COVID-19 was higher in adults age ≥65 years (35%; 95% CI, 24%-47%) than in those age 18-64 years (13%; 95% CI, 9%-17%) after the booster.

Conclusions

In this study, mRNA-1273 was more effective than BNT162b2 or Ad26.COV2.S following a primary series during the Delta-dominant period and more effective than BNT162b2 as a booster during the Omicron-dominant period.

Genetic and molecular architecture of familial hypercholesterolemia

Atherosclerotic cardiovascular disease is the leading cause of death globally. Despite its important risk of premature atherosclerosis and cardiovascular disease, familial hypercholesterolemia (FH) is still largely underdiagnosed worldwide. It is one of the most frequently inherited diseases due to mutations, for autosomal dominant forms, in either of the LDLR, APOB, and PCSK9 genes or possibly a few mutations in the APOE gene and, for the rare autosomal forms, in the LDLRAP1 gene. The discovery of the genes implicated in the disease has largely helped to improve the diagnosis and treatment of FH from the LDLR by Brown and Goldstein, as well as the introduction of statins, to PCSK9 discovery in FH by Abifadel et al., and the very rapid availability of PCSK9 inhibitors. In the last two decades, major progress has been made in clinical and genetic diagnostic tools and the therapeutic arsenal against FH. Improving prevention, diagnosis, and treatment and making them more accessible to all patients will help reduce the lifelong burden of the disease.

Agreement in the CARTaGENE cohort between self-reported medication use and claim data

OBJECTIVES

To describe the agreement of self-reported medication use with claim prescription records and to ascertain factors associated with agreement between the two data sources.

METHODS

Baseline data on self-reported medication use was extracted from CARTaGENE, a cohort study in Quebec, Canada, and from the provincial health insurance records (dispensation database) of the same individuals. Kappa statistics were used to estimate concordance beyond chance between the two data sources. Logistic regression models were adjusted to estimate the association between agreement and selected individual's characteristics (sex, age, education, region, income, utilization of health care system, and comorbidities).

RESULTS

Agreement between self-reported medication use and administrative data varied considerably across medication classes (kappa 0.54 for respiratory system and 0.91 for systemic hormonal preparations). Overall, agreement improved when a fixed time window of 90 days was used for exposure measurement. Sex, education level, frequency of health care use and the number of reported medications were associated with agreement.

DISCUSSION

Overall, there was a reasonable agreement between the two data sources, but important variations were found for the different drug classes. These results could be used by researchers to more accurately assess drug exposures using real-world data, which are increasingly important to regulators.

A Risk Score to Detect Subclinical Rheumatoid Arthritis-Associated Interstitial Lung Disease

OBJECTIVE

Patients at high risk of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) would benefit from being identified before the onset of respiratory symptoms; this can be done by screening patients with the use of chest high-resolution computed tomography (HRCT). Our objective was to develop and validate a risk score for patients who have subclinical RA-ILD.

METHODS

Our study included a discovery population and a replication population from 2 prospective RA cohorts (ESPOIR and TRANSLATE2, respectively) without pulmonary symptoms who had received chest HRCT scans. All patients were genotyped for MUC5B rs35705950. After multiple logistic regression, a risk score based on independent risk factors for subclinical RA-ILD was developed in the discovery population and tested for validation in the replication population.

RESULTS

The discovery population included 163 patients with RA, and the replication population included 89 patients with RA. The prevalence of subclinical RA-ILD was 19.0% and 16.9%, respectively. In the discovery population, independent risk factors for subclinical RA-ILD were presence of the MUC5B rs35705950 T allele (odds ratio [OR] 3.74 [95% confidence interval (95% CI) 1.37, 10.39]), male sex (OR 3.93 [95% CI 1.40, 11.39]), older age at RA onset (for each year, OR 1.10 [95% CI 1.04, 1.16]), and increased mean Disease Activity Score in 28 joints using the erythrocyte sedimentation rate (for each unit, OR 2.03 [95% CI 1.24, 3.42]). We developed and validated a derived risk score with receiver operating characteristic areas under the curve of 0.82 (95% CI 0.70-0.94) for the discovery population and 0.78 (95% CI 0.65-0.92) for the replication population. Excluding MUC5B rs35705950 from the model provided a lower goodness of fit (likelihood ratio test, P = 0.01).

CONCLUSION

We developed and validated a risk score that could help identify patients at high risk of subclinical RA-ILD. Our findings support an important contribution of MUC5B rs35705950 to subclinical RA-ILD risk.

Angiotensin receptor blockers and β blockers in Marfan syndrome: an individual patient data meta-analysis of randomised trials

BACKGROUND

Angiotensin receptor blockers (ARBs) and β blockers are widely used in the treatment of Marfan syndrome to try to reduce the rate of progressive aortic root enlargement characteristic of this condition, but their separate and joint effects are uncertain. We aimed to determine these effects in a collaborative individual patient data meta-analysis of randomised trials of these treatments.

METHODS

In this meta-analysis, we identified relevant trials of patients with Marfan syndrome by systematically searching MEDLINE, Embase, and CENTRAL from database inception to Nov 2, 2021. Trials were eligible if they involved a randomised comparison of an ARB versus control or an ARB versus β blocker. We used individual patient data from patients with no prior aortic surgery to estimate the effects of: ARB versus control (placebo or open control); ARB versus β blocker; and indirectly, β blocker versus control. The primary endpoint was the annual rate of change of body surface area-adjusted aortic root dimension Z score, measured at the sinuses of Valsalva.

FINDINGS

We identified ten potentially eligible trials including 1836 patients from our search, from which seven trials and 1442 patients were eligible for inclusion in our main analyses. Four trials involving 676 eligible participants compared ARB with control. During a median follow-up of 3 years, allocation to ARB approximately halved the annual rate of change in the aortic root Z score (mean annual increase 0·07 [SE 0·02] ARB vs 0·13 [SE 0·02] control; absolute difference -0·07 [95% CI -0·12 to -0·01]; p=0·012). Prespecified secondary subgroup analyses showed that the effects of ARB were particularly large in those with pathogenic variants in fibrillin-1, compared with those without such variants (heterogeneity p=0·0050), and there was no evidence to suggest that the effect of ARB varied with β-blocker use (heterogeneity p=0·54). Three trials involving 766 eligible participants compared ARBs with β blockers. During a median follow-up of 3 years, the annual change in the aortic root Z score was similar in the two groups (annual increase -0·08 [SE 0·03] in ARB groups vs -0·11 [SE 0·02] in β-blocker groups; absolute difference 0·03 [95% CI -0·05 to 0·10]; p=0·48). Thus, indirectly, the difference in the annual change in the aortic root Z score between β blockers and control was -0·09 (95% CI -0·18 to 0·00; p=0·042).

INTERPRETATION

In people with Marfan syndrome and no previous aortic surgery, ARBs reduced the rate of increase of the aortic root Z score by about one half, including among those taking a β blocker. The effects of β blockers were similar to those of ARBs. Assuming additivity, combination therapy with both ARBs and β blockers from the time of diagnosis would provide even greater reductions in the rate of aortic enlargement than either treatment alone, which, if maintained over a number of years, would be expected to lead to a delay in the need for aortic surgery.

FUNDING

Marfan Foundation, the Oxford British Heart Foundation Centre for Research Excellence, and the UK Medical Research Council.

Low circulating PCSK9 levels in LPL homozygous children with chylomicronemia syndrome in a syrian refugee family in Lebanon

Familial chylomicronemia syndrome is a rare autosomal recessive disorder of lipoprotein metabolism characterized by the presence of chylomicrons in fasting plasma and an important increase in plasma triglycerides (TG) levels that can exceed 22.58 mmol/l. The disease is associated with recurrent episodes of abdominal pain and pancreatitis, eruptive cutaneous xanthomatosis, lipemia retinalis, and hepatosplenomegaly. A consanguineous Syrian family who migrated to Lebanon was referred to our laboratory after perceiving familial chylomicronemia syndrome in two children. The LPL and PCSK9 genes were sequenced and plasma PCSK9 levels were measured. Sanger sequencing of the LPL gene revealed the presence of the p.(Val227Phe) pathogenic variant in exon 5 at the homozygous state in the two affected children, and at the heterozygous state in the other recruited family members. Interestingly, PCSK9 levels in homozygous carriers of the p.(Val227Phe) were ≈50% lower than those in heterozygous carriers of the variant (p-value = 0.13) and ranged between the 5th and the 7.5th percentile of PCSK9 levels in a sample of Lebanese children of approximately the same age group. Moreover, this is the first reported case of individuals carrying simultaneously an LPL pathogenic variant and PCSK9 variants, the L10 and L11 leucine insertion, which can lower and raise low-density lipoprotein cholesterol (LDL-C) levels respectively. TG levels fluctuated concomitantly between the two children, were especially high following the migration from a country to another, and were reduced under a low-fat diet. This case is crucial to raise public awareness on the risks of consanguineous marriages to decrease the emergence of inherited autosomal recessive diseases. It also highlights the importance of the early diagnosis and management of these diseases to prevent serious complications, such as recurrent pancreatitis in the case of familial hyperchylomicronemia.

The critical role of the TB5 domain of Fibrillin-1 in endochondral ossification

Mutations in the Fibrillin-1 (FBN1) gene are responsible for the autosomal dominant form of Geleophysic Dysplasia (GD), which is characterized by short stature and extremities, thick skin, and cardiovascular disease. All known FBN1 mutations in GD patients are localized within the region encoding the TB5 (TGF-β binding protein-like 5) domain of this protein. Herein, we generated a knock-in mouse model, Fbn1Y1698C by introducing the p.Tyr1696Cys mutation from a GD patient into the TB5 domain of murine Fbn1 to elucidate the specific role of this domain in endochondral ossification. We found that both Fbn1Y1698C/+ and Fbn1Y1698C/Y1698C mice exhibited a reduced stature reminiscent of the human GD phenotype. The Fbn1 point mutation introduced in these mice affected the growth plate formation owing to abnormal chondrocyte differentiation such that mutant chondrocytes failed to establish a dense microfibrillar network composed of fibrillin-1. This original Fbn1 mutant mouse model offers new insight into the pathogenic events underlying GD. Our findings suggest that the etiology of GD involves the dysregulation of the ECM composed by abnormal fibrillin-1 microfibril network impacting the differentiation of the chondrocytes.

POS0062 A RISK SCORE TO DETECT SUBCLINICAL RHEUMATOID ARTHRITIS-ASSOCIATED INTERSTITIAL LUNG DISEASE

Background

Despite a high morbi-mortality rate, there are no definite strategy for subclinical interstitial lung disease (ILD) screening in patients with rheumatoid arthritis (RA).

Objectives

Our objectives were: 1. to identify risk factors for subclinical RA-ILD in a prospective discovery cohort (ESPOIR) 2.to develop a risk score for subclinical RA-ILD and 3. to validate the risk score in an independent replication cohort (TRANSLATE 2).

Methods

Patients without pulmonary symptoms from 2 prospective RA cohorts who underwent chest HRCT scans were included. All patients were genotyped for MUC5B rs35705950. A risk score based on independent risk factors for subclinical RA-ILD was developed using multiple logistic regression in the discovery cohort. The risk score was tested for validation in the replication cohort.

Results

Discovery and replication cohorts included 163 and 89 patients, respectively. Subclinical ILD was detected in 19.0% and 16.9% of the patients, respectively. In the discovery cohort, independent risk factors for subclinical RA-ILD were the MUC5B rs35705950 T risk allele (odds ratio [OR]=3.74; 95% confidence interval [CI] [1.37–10.39], male sex (OR=3.93; 95%CI [1.40–11.39]), older age at RA onset (for each year, OR=1.10; 95%CI [1.04–1.16]) and increased mean DAS28-ESR (for each unit, OR=2.03; 95%CI [1.24–3.42]). We developed a risk score for subclinical RA-ILD with AUC=0.82; 95%CI [0.70–0.94] (sensitivity (Se)=71.0%) and specificity (Sp)=79.6%). The risk score was validated in the replication cohort with AUC=0.78; 95%CI [0.65–0.92] (Se=86.7%, Sp=62.2%).

Conclusion

Our risk score could help identifying patients at high-risk for subclinical RA-ILD before the onset of pulmonary symptoms.

Disclosure of Interests

Pierre-Antoine Juge Speakers bureau: AstraZeneca, Boehringer Ingelheim, Bristol Myers Squibb, Consultant of: Bristol Myers Squibb, Benjamin Granger: None declared, Marie-Pierre Debray: None declared, Esther Ebstein: None declared, Fabienne Louis-Sidney: None declared, Joanna KEDRA: None declared, Tracy Doyle: None declared, Raphael Borie: None declared, Arnaud Constantin Consultant of: Abbvie, Amgen, Biogen, BMS, Boehringer Ingelheim, Fresenius Kabi, Galapagos, Janssen, Lilly, Medac, MSD, Mylan, Novartis, Pfizer, Procter & Gamble, Roche, Sanofi, UCB, Viatris, Bernard Combe Consultant of: AbbVie, BMS, Eli-Lilly, Gilead, Janssen, Merck, Novartis, Pfizer, Roche-Chugai, Sanofi, UCB, René-Marc Flipo Consultant of: Abbvie, Janssen, MSD and Pfizer. He reports research grants from Abbvie, Janssen, Novartis and Pfizer, Xavier Mariette Consultant of: BMS, Gilead, Janssen, Pfizer, Samsung, UCB, Olivier VITTECOQ: None declared, Alain Saraux: None declared, Guillermo CARVAJAL ALEGRIA: None declared, Jean Sibilia Consultant of: AbbVie, Lilly, MSD, Amgen, Pfizer, BMS, Janssen, Roche, Sandoz, Sanofi-Genzyme, SOBI, UCB, Novartis, Grant/research support from: AbbVie, Lilly, MSD, Amgen, Pfizer, BMS, Janssen, Roche, Sandoz, Sanofi-Genzyme, SOBI, UCB, Novartis, Francis Berenbaum: None declared, Caroline Kannengiesser: None declared, Catherine Boileau: None declared, Jeffrey Sparks Consultant of: AbbVie, Boehringer Ingelheim, Bristol Myers Squibb, Gilead, Inova Diagnostics, Janssen, Optum, and Pfizer, Grant/research support from: National Institute of Arthritis and Musculoskeletal and Skin Diseases (grant numbers R01 AR077607, P30 AR070253, and P30 AR072577), The R. Bruce and Joan M. Mickey Research Scholar Fund, Bristol Myers Squibb,

Bruno Crestani Speakers bureau: Boehringer Ingelheim, AstraZeneca, Roche, Sanofi, Grant/research support from: MedImmune, Roche, Boehringer Ingelheim, Bruno Fautrel Consultant of: AbbVie, Amgen, Biogen, BMS, Celgene, Fresenius Kabi, Janssen, Lilly, Medac, MSD, NORDIC Pharma, Novartis, Pfizer, Roche, SOBI, UCB, Grant/research support from: AbbVie, Lilly, MSD, Pfizer, Philippe Dieudé Speakers bureau: Roche – Chugai, Bristol Myers Squibb, Consultant of: Pfizer, Roche – Chugai, Bristol Myers Squibb, Abbvie, MSD, Grant/research support from: Novartis

Determinants of survival after lung transplantation in telomerase-related gene mutation carriers: A retrospective cohort

Carriers of germline telomerase-related gene (TRG) mutations can show poor prognosis, with an increase in common hematological complications after lung transplantation (LT) for pulmonary fibrosis. The aim of this study was to describe the outcomes after LT in recipients carrying a germline TRG mutation and to identify the predictors of survival. In a multicenter cohort of LT patients, we retrospectively reviewed those carrying pathogenic TRG variations (n = 38; TERT, n = 23, TERC, n = 9, RTEL1, n = 6) between 2009 and 2018. The median age at LT was 54 years (interquartile range [IQR] 46-59); 68% were male and 71% had idiopathic pulmonary fibrosis. During the diagnosis of pulmonary fibrosis, 28 (74%) had a hematological disease, including eight with myelodysplasia. After a median follow-up of 26 months (IQR 15-46), 38 patients received LT. The overall post-LT median survival was 3.75 years (IQR 1.8-NA). The risk of death after LT was increased for patients with myelodysplasia (HR 4.1 [95% CI 1.5-11.5]) or short telomere (HR 2.2 [1.0-5.0]) before LT. After LT, all patients had anemia, 66% had thrombocytopenia, and 39% had neutropenia. Chronic lung allograft dysfunction frequency was 29% at 4 years. The present findings support the use of LT in TRG mutation carriers without myelodysplasia. Hematological evaluation should be systematically performed before LT.

Whole Exome/Genome Sequencing Joint Analysis of a Family with Oligogenic Familial Hypercholesterolemia

Autosomal Dominant Hypercholesterolemia (ADH) is a genetic disorder caused by pathogenic variants in LDLR, APOB, PCSK9 and APOE genes. We sought to identify new candidate genes responsible for the ADH phenotype in patients without pathogenic variants in the known ADH-causing genes by focusing on a French family with affected and non-affected members who presented a high ADH polygenic risk score (wPRS). Linkage analysis, whole exome and whole genome sequencing resulted in the identification of variants p.(Pro398Ala) in CYP7A1, p.(Val1382Phe) in LRP6 and p.(Ser202His) in LDLRAP1. A total of 6 other variants were identified in 6 of 160 unrelated ADH probands: p.(Ala13Val) and p.(Aps347Asn) in CYP7A1; p.(Tyr972Cys), p.(Thr1479Ile) and p.(Ser1612Phe) in LRP6; and p.(Ser202LeufsTer19) in LDLRAP1. All six probands presented a moderate wPRS. Serum analyses of carriers of the p.(Pro398Ala) variant in CYP7A1 showed no differences in the synthesis of bile acids compared to the serums of non-carriers. Functional studies of the four LRP6 mutants in HEK293T cells resulted in contradictory results excluding a major effect of each variant alone. Within the family, none of the heterozygous for only the LDLRAP1 p.(Ser202His) variant presented ADH. Altogether, each variant individually does not result in elevated LDL-C; however, the oligogenic combination of two or three variants reveals the ADH phenotype.

Genotype-Phenotype Relationships in Inheritable Idiopathic Pulmonary Fibrosis: A Greek National Cohort Study

BACKGROUND

Monogenic and polygenic inheritances are evidenced for idiopathic pulmonary fibrosis (IPF). Pathogenic variations in surfactant protein-related genes, telomere-related genes (TRGs), and a single-nucleotide polymorphism in the promoter of MUC5B gene encoding mucin 5B (rs35705950 T risk allele) are reported. This French-Greek collaborative study, Gen-Phen-Re-GreekS in inheritable IPF (iIPF), aimed to investigate genetic components and patients' characteristics in the Greek national IPF cohort with suspected heritability.

PATIENTS AND METHODS

150 patients with familial PF, personal-family extrapulmonary disease suggesting short telomere syndrome, and/or young age IPF were analyzed.

RESULTS

MUC5B rs35705950 T risk allele was detected in 103 patients (90 heterozygous, 13 homozygous, allelic frequency of 39%), monoallelic TRG pathogenic variations in 19 patients (8 TERT, 5 TERC, 2 RTEL1, 2 PARN, 1 NOP10, and 1 NHP2), and biallelic ABCA3 pathogenic variations in 3. Overlapping MUC5B rs35705950 T risk allele and TRG pathogenic variations were shown in 11 patients (5 TERT, 3 TERC, 1 PARN, 1 NOP10, and 1 NHP2), MUC5B rs35705950 T risk allele, and biallelic ABCA3 pathogenic variations in 2. In 38 patients, neither MUC5B rs35705950 T risk allele nor TRG pathogenic variations were detectable. Kaplan-Meier curves showed differences in time-to-death (p = 0.025) where patients with MUC5B rs35705950 T risk allele alone or in combination with TRG pathogenic variations presented better prognosis.

CONCLUSION

The Gen-Phen-Re-GreekS in iIPF identified multiple and overlapping genetic components including the rarest, underlying disease's genetic "richesse," complexity and heterogeneity. Time-to-death differences may relate to diverse IPF pathogenetic mechanisms implicating "personalized" medical care driven by genotypes in the near future.

Posttranscriptional Regulation of the Human LDL Receptor by the U2-Spliceosome

BACKGROUND

The LDLR (low-density lipoprotein receptor) in the liver is the major determinant of LDL-cholesterol levels in human plasma. The discovery of genes that regulate the activity of LDLR helps to identify pathomechanisms of hypercholesterolemia and novel therapeutic targets against atherosclerotic cardiovascular disease.

METHODS

We performed a genome-wide RNA interference screen for genes limiting the uptake of fluorescent LDL into Huh-7 hepatocarcinoma cells. Top hit genes were validated by in vitro experiments as well as analyses of data sets on gene expression and variants in human populations.

RESULTS

The knockdown of 54 genes significantly inhibited LDL uptake. Fifteen of them encode for components or interactors of the U2-spliceosome. Knocking down any one of 11 out of 15 genes resulted in the selective retention of intron 3 of LDLR. The translated LDLR fragment lacks 88% of the full length LDLR and is detectable neither in nontransfected cells nor in human plasma. The hepatic expression of the intron 3 retention transcript is increased in nonalcoholic fatty liver disease as well as after bariatric surgery. Its expression in blood cells correlates with LDL-cholesterol and age. Single nucleotide polymorphisms and 3 rare variants of one spliceosome gene, RBM25, are associated with LDL-cholesterol in the population and familial hypercholesterolemia, respectively. Compared with overexpression of wild-type RBM25, overexpression of the 3 rare RBM25 mutants in Huh-7 cells led to lower LDL uptake.

CONCLUSIONS

We identified a novel mechanism of posttranscriptional regulation of LDLR activity in humans and associations of genetic variants of RBM25 with LDL-cholesterol levels.

ADAMTS Proteins and Vascular Remodeling in Aortic Aneurysms

Extracellular matrix (ECM) in the vascular wall is a highly dynamic structure composed of a set of different molecules such as elastins, collagens, fibronectin (Fn), laminins, proteoglycans, and polysaccharides. ECM undergoes remodeling processes to regulate vascular smooth muscle and endothelial cells' proliferation, differentiation, and adhesion. Abnormalities affecting the ECM can lead to alteration in cellular behavior and from this, this can conduce to the development of pathologies. Metalloproteases play a key role in maintaining the homeostasis of ECM by mediating the cleavage of different ECM components. There are different types of metalloproteases: matrix metalloproteinases (MMPs), disintegrin and metalloproteinases (ADAMs), and ADAMs with thrombospondin motifs (ADAMTSs). ADAMTSs have been found to participate in cardiovascular physiology and diseases and specifically in aortic aneurysms. This review aims to decipher the potential role of ADAMTS proteins in the physiopathologic development of Thoracic Aortic Aneurysms (TAA) and Abdominal Aortic Aneurysms (AAA). This review will focus on what is known on the ADAMTS family involved in human aneurysms from human tissues to mouse models. The recent findings on THSD4 (encoding ADAMTSL6) mutations in TAA give a new insight on the involvement of the ADAMTS family in TAA.

Cooperative Mechanism of ADAMTS/ ADAMTSL and Fibrillin-1 in the Marfan Syndrome and Acromelic Dysplasias

The term “fibrillinopathies” gathers various diseases with a wide spectrum of clinical features and severity but all share mutations in the fibrillin genes. The first described fibrillinopathy, Marfan syndrome (MFS), is a multisystem disease with a unique combination of skeletal, thoracic aortic aneurysm (TAA) and ocular features. The numerous FBN1 mutations identified in MFS are located all along the gene, leading to the same pathogenic mechanism. The geleophysic/acromicric dysplasias (GD/AD), characterized by short stature, short extremities, and joint limitation are described as “the mirror image” of MFS. Previously, in GD/AD patients, we identified heterozygous FBN1 mutations all affecting TGFβ-binding protein-like domain 5 (TB5). ADAMTS10, ADAMTS17 and, ADAMTSL2 are also involved in the pathogenic mechanism of acromelic dysplasia. More recently, in TAA patients, we identified mutations in THSD4, encoding ADAMTSL6, a protein belonging to the ADAMTSL family suggesting that ADAMTSL proteins are also involved in the Marfanoid spectrum. Together with human genetic data and generated knockout mouse models targeting the involved genes, we provide herein an overview of the role of fibrillin-1 in opposite phenotypes. Finally, we will decipher the potential biological cooperation of ADAMTS-fibrillin-1 involved in these opposite phenotypes.

Family history of aortic dissection is not a risk factor in Marfan syndrome with a FBN1 gene mutation

Background

A history family of aortic dissection was considered as a risk factor for aortic dissection in patients with Marfan syndrome with a FBN1 mutation.

Objectives

Evaluate whether a family history of aortic dissection is a risk marker for dissection in this population

Methods

Retrospective study of patients coming to the reference centre between 1996 and 2018, carrying a FBN1 gene mutation. Pedigrees were obtained for each patient, and familial screening actively pursued. Patients with a family history of aortic dissection were compared with patients without family history of aortic dissection.

Results

1700 patients (age 33.2 (±17) years, 51% women) with a FBN1 gene mutation were included. 145 (8,5%) patients underwent aortic dissection at a mean age of 37.9 (±11.4) years and 323 (19%) patients had been operated at 33.8 (±13.9) years.

481 patients had a family history of aortic dissection, including 38 who dissected themselves, and 88 who underwent surgery. 1219 had no family history of aortic dissection, including 107 who dissected themselves, and 235 who underwent surgery.

Therefore, the personal risk for aortic dissection was similar in patients with and without a family history of aortic dissection (38/481, i.e. 7.9% vs 107/1219, i.e. 8.8%), as was the personal risk for prophylactic aortic surgery (88/481, i.e. 18.3% vs. 253/1219, i.e. 17.2%), and the risk for either aortic dissection or prophylactic aortic surgery (118/481, i.e. 24.5% vs. 328/1219, i.e. 26.9%).

Conclusions

In Marfan syndrome with a FBN1 gene mutation, a family history of aortic dissection is not a marker of aortic disease severity.

Funding Acknowledgement

Type of funding sources: None.

Genotype-phenotype correlations in Marfan syndrome patients with FBN1 mutations: a cohort study on 1575 patients

Background

Marfan syndrome (MFS) is a connective tissue disorder in which several systems are affected with great phenotypic variability. Although known to be associated with pathogenic variants in the FBN1 gene, few genotype-phenotype correlations have been found in probands' studies only.

Purpose

The aim of this study is to provide survival curves and genotype-phenotype correlations in all patients with FBN1 mutations, probands and relatives.

Methods

We established survival curves and sought genotype–phenotype correlations in a population of 1575 consecutive MFS patients with pathogenic class 4 or 5 variants in the FBN1 gene. This population represents the most comprehensive clinical database worldwide on MFS.

Results

Global survival was 90% at 60 years. However, lifelong aortic event rate (either dissection or surgery) and survival were impacted by the genotype. Premature termination codons (PTC), resulting in haploinsufficiency, were associated with a shorter life expectancy and a high lifelong risk of an aortic event (83%). Interestingly, these variants were also associated with the highest risk of severe scoliosis (52%) and with a lower risk for ectopia lentis (EL) surgery (13%). Dominant negative in-frame pathogenic variants could be subdivided according to their impact on the cysteine content of fibrillin-1: cysteine loss (–Cys) was associated with high aortic risk (73%) and a higher frequency of EL surgery (43%); cysteine addition was associated with moderate aortic risk (29%) and the highest frequency of EL surgery (48%); unchanged cysteine content was associated with high aortic risk (61%) and lower frequency of EL surgery (23%). No gene-region effect was observed, except for a more severe phenotype for in-frame variants with cysteine loss within the “neonatal region”. Aortic risk was greater for males in all subgroups, and probands were more severely affected.

Conclusions

MFS genotype-phenotype correlations related to pathogenic FBN1 variants exist for aortic and extra-aortic features. This leads us to propose new tools to refine the prognosis in this population. Preventive therapy with β-blockers and restricted exercise should be proposed regardless of the aortic diameter in the high aortic risk groups (PTC and –Cys variants). These results have major consequences on genetic counseling and personalized medicine for patients carrying a FBN1 mutation. This study also improves the overall understanding of the role of FBN1 in various organs.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Fondation Coeur et Recherche, Paris, FranceFédération Française de Cardiologie, Paris, France Patients with PTC vs. in-frame mutationsDifferences within in-frame mutations

Plasma PCSK9 levels increase following percutaneous coronary interventions

Background

Beside its role in cholesterol homeostasis, Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) has been associated with the processes of vascular inflammation and atherosclerosis. The protein is expressed in endothelial cells, smooth muscle cells and macrophages and it is detected inside the human atherosclerotic plaque.

Purpose

We aimed to investigate the effect of acute inflammation associated with plaque rupture and vascular injury during elective percutaneous coronary intervention (PCI) on plasma levels of PCSK9 in patients with coronary artery disease (CAD).

Methods

We measured PCSK9, C-reactive protein (CRP), Interleukin-6 (IL-6) and high-sensitivity cardiac Troponin T (hs-cTnT) plasma levels immediately before and 18–24 hours after PCI via the radial approach, in 68 consecutive patients with stable CAD referred for elective PCI of a de novo lesion in a native coronary artery. Patients with unstable coronary syndrome &lt;3 months old, baseline inflammatory condition, malignancy, auto-immune disease or intervention via the femoral access, were excluded.

Results

All patients were treated with balloon angioplasty and implantation of a second-generation drug eluting stent (DES). Baseline plasma levels of PCSK9 were higher in women and in patients treated with statins. At 18–24 hours after the procedure, plasma levels of PCSK9, CRP, IL-6 and hs-cTnT increased significantly compared to baseline (table). The change (elevation) in CRP plasma levels was statistically correlated with that of IL-6 (r=0.33; p=0.006) and with that of hs-cTnT (r=0.28; p=0.023). However, there was no correlation between the change (elevation) in plasma PCSK9 levels and those of IL-6 (r=−0.09; p=0.47), CRP (r=0.01; p=0.9), and hs-cTnT (r=0.1; p=0.41).

Conclusions

Plasma levels of PCSK9 increased by 26% following PCI with DES. That elevation was however, not correlated with the degree of myocardial injury (hs-cTnT) or of inflammation (IL-6 and CRP). The mechanism underlying PCK9 elevation post PCI requires further investigation.

Funding Acknowledgement

Type of funding sources: None.

Inhibition of HIPK2 Alleviates Thoracic Aortic Disease in Mice With Progressively Severe Marfan Syndrome

Objective

Despite considerable research, the goal of finding nonsurgical remedies against thoracic aortic aneurysm and acute aortic dissection remains elusive. We sought to identify a novel aortic PK (protein kinase) that can be pharmacologically targeted to mitigate aneurysmal disease in a well-established mouse model of early-onset progressively severe Marfan syndrome (MFS).

Approach and Results

Computational analyses of transcriptomic data derived from the ascending aorta of MFS mice predicted a probable association between thoracic aortic aneurysm and acute aortic dissection development and the multifunctional, stress-activated HIPK2 (homeodomain-interacting protein kinase 2). Consistent with this prediction, Hipk2 gene inactivation significantly extended the survival of MFS mice by slowing aneurysm growth and delaying transmural rupture. HIPK2 also ranked among the top predicted PKs in computational analyses of DEGs (differentially expressed genes) in the dilated aorta of 3 MFS patients, which strengthened the clinical relevance of the experimental finding. Additional in silico analyses of the human and mouse data sets identified the TGF (transforming growth factor)-β/Smad3 signaling pathway as a potential target of HIPK2 in the MFS aorta. Chronic treatment of MFS mice with an allosteric inhibitor of HIPK2-mediated stimulation of Smad3 signaling validated this prediction by mitigating thoracic aortic aneurysm and acute aortic dissection pathology and partially improving aortic material stiffness.

Conclusions

HIPK2 is a previously unrecognized determinant of aneurysmal disease and an attractive new target for antithoracic aortic aneurysm and acute aortic dissection multidrug therapy.

Identification of a Variant in APOB Gene as a Major Cause of Hypobetalipoproteinemia in Lebanese Families

Familial hypobetalipoproteinemia (FHBL) is a codominant genetic disorder characterized by reduced plasma levels of low-density lipoprotein cholesterol and apolipoprotein B. To our knowledge, no study on FHBL in Lebanon and the Middle East region has been reported. Therefore, we conducted genetic studies in unrelated families and probands of Lebanese origin presenting with FHBL, in order to identify the causes of this disease. We found that 71% of the recruited probands and their affected relatives were heterozygous for the p.(Arg490Trp) variant in the APOB gene. Haplotype analysis showed that these patients presented the same mutant haplotype. Moreover, there was a decrease in plasma levels of PCSK9 in affected individuals compared to the non-affected and a significant positive correlation between circulating PCSK9 and ApoB levels in all studied probands and their family members. Some of the p.(Arg490Trp) carriers suffered from diabetes, hepatic steatosis or neurological problems. In conclusion, the p.(Arg490Trp) pathogenic variant seems a cause of FHBL in patients from Lebanese origin, accounting for approximately 70% of the probands with FHBL presumably as a result of a founder mutation in Lebanon. This study is crucial to guide the early diagnosis, management and prevention of the associated complications of this disease.

MUC5B promoter variant rs35705950 and rheumatoid arthritis associated interstitial lung disease survival and progression

BACKGROUND

The major risk factor for idiopathic pulmonary fibrosis (IPF), MUC5B rs35705950, was found to be associated with rheumatoid arthritis-associated interstitial lung disease (RA-ILD). Whilst the MUC5B rs35705950 T risk allele has been associated with better survival in IPF, its impact on RA-ILD prognosis remains to be determined. Our objective was to explore the influence of MUC5B rs35705950 on survival and progression in RA-ILD.

METHODS

Through an international retrospective observational study, patients with RA-ILD were genotyped for the MUC5B rs35705950 variant and consecutive pulmonary function tests (PFTs) findings were collected. Longitudinal data up to a 10-year follow-up were considered and analyzed using mixed regression models. Proportional hazards and joint proportional hazards models were used to analyze the association of baseline and longitudinal variables with lung transplant-free survival. Significant progression of RA-ILD was defined as at least an absolute or relative 10% decline of forced vital capacity at 2 years from baseline.

RESULTS

Out of 321 registered patients, 261 were included in the study: 139 women (53.3%), median age at RA-ILD diagnosis 65 years (interquartile range [IQR] 57 to 71), 151 ever smokers (59.2%). Median follow-up was 3.5 years (IQR 1.3 to 6.6). Mortality rate was 32% (95%CI 19 to 42) at 10 years. The MUC5B rs35705950 variant did not impact lung transplant-free survival (HR for the T risk allele carriers=1.26; 95%CI 0.61 to 2.62; P=0.53). Decline in pulmonary function at 2 years was not influenced by MUC5B rs35705950 (OR=0.95; 95%CI 0.44 to 2.05; P=0.89), irrespective of the HRCT pattern.

CONCLUSION

In this study, the MUC5B rs35705950 promoter variant did not influence transplant- free survival or decline in pulmonary function in patients with RA-ILD.

APOE gene variants in primary dyslipidemia

Apolipoprotein E (apoE) is a major apolipoprotein involved in lipoprotein metabolism. It is a polymorphic protein and different isoforms are associated with variations in lipid and lipoprotein levels and thus cardiovascular risk. The isoform apoE4 is associated with an increase in LDL-cholesterol levels and thus a higher cardiovascular risk compared to apoE3. Whereas, apoE2 is associated with a mild decrease in LDL-cholesterol levels. In the presence of other risk factors, apoE2 homozygotes could develop type III hyperlipoproteinemia (familial dysbetalipoproteinemia or FD), an atherogenic disorder characterized by an accumulation of remnants of triglyceride-rich lipoproteins. Several rare APOE gene variants were reported in different types of dyslipidemias including FD, familial combined hyperlipidemia (FCH), lipoprotein glomerulopathy and bona fide autosomal dominant hypercholesterolemia (ADH). ADH is characterized by elevated LDL-cholesterol levels leading to coronary heart disease, and due to molecular alterations in three main genes: LDLR, APOB and PCSK9. The identification of the APOE-p.Leu167del variant as the causative molecular element in two different ADH families, paved the way to considering APOE as a candidate gene for ADH. Due to non mendelian interacting factors, common genetic and environmental factors and perhaps epigenetics, clinical presentation of lipid disorders associated with APOE variants often strongly overlap. More studies are needed to determine the spectrum of APOE implication in each of the diseases, notably ADH, in order to improve clinical and genetic diagnosis, prognosis and patient management. The purpose of this review is to comment on these APOE variants and on the molecular and clinical overlaps between dyslipidemias.

POS0095 DEVELOPPING A SCORE TO PREDICT PRECLINICAL INTERSTITIAL LUNG DISEASE IN PATIENTS WITH RHEUMATOID ARTHRITIS – A CROSS-SECTIONAL STUDY FROM THE ESPOIR COHORT

Background:

Interstitial lung disease (ILD) is an extra-articular manifestation of rheumatoid arthritis (RA) detected in 20% to 60% of patients with RA on high-resolution computed-tomography (HRCT) chest scan and is clinically significant in near 10%. Despite a high morbi-mortality rate, a definite strategy for preclinical ILD screening in patients with RA remains to be determined. To date, several factors have been reported to increase the risk of RA-ILD occurrence (i.e. older age at RA onset, ACPA positivity, male sex, RA disease activity, the MUC5B rs35705950 promoter variant...). However, none of these risk factors has been validated in a prospective cohort of patients with RA. The ESPOIR prospective cohort includes patients aged 18 to 70 years with recent arthritis (less than 6 months) and a definite or probable diagnosis of RA.

Objectives:

To identify in the ESPOIR cohort factors associated with ILD after at least 10 years of RA duration in order to develop a predictive score to identify patients with preclinical RA-ILD.

Methods:

An ILD detection by chest HRCT scan was systematically offered to every patient with definite RA after at least 10 years-follow-up. Chest HRCT scans were centrally reviewed by an experienced radiologist. Potential predictors of ILD were prospectively collected from baseline to the date of the HRCT scan, and all included patients were genotyped for MUC5B rs35705950. To take into account repeated measures, trajectories were determined for disease activity, C reactive protein, smoking, treatment exposure (i.e. prednisone, methotrexate [MTX] and biological disease modifying anti-rheumatic drugs [bDMARDs]). A logistic model was used to identify independent predictors for the occurrence of ILD on HRCT scans. Confidence intervals were estimated using sampling methods. A predictive score for preclinical ILD occurrence was developed based on the identified predictors.

Results:

163 RA patients according to 2010 ACR/EULAR classification criteria, none of whom had pulmonary symptoms, were investigated with a chest HRCT scan (128 women (78.5%), mean RA duration 13.7 ± 1.1 years, age at inclusion 47.6 y/o ± 10.4, mean disease activity score [DAS]-28 during follow up was 3.1 ± 1.0). ILD was detected in 31 patients (19.0%). The MUC5B rs35705950 minor allele frequency (MAF) was 22.2% and 10.0% in the RA-ILD and RA-noILD populations, respectively (OR univariate=2.6 CI95% [1.2-5.5], P=0.01). After logistic regression, independent predictors for preclinical RA-ILD were male sex (OR=3.9 CI95% [1.4-11.4]), older age at RA onset (OR=1.1 per year CI95% [1.0-1.2]), mean DAS-28 score during the follow-up (OR=2.0 CI95% [1.2-3.4]) and MUC5B rs35705950 T risk allele (OR=3.7 CI95% [1.4-10.4]) (Figure 1). No influence of the use of RA-related drugs (prednisone, MTX or bDMARDs) was identified as risk factor. The logistic model could predict preclinical ILD occurrence after 13 years of RA duration with an AUC=0.82 CI95% (0.72-0.91). A predictive score for preclinical RA-ILD based on the 4 identified predictive risk factors was developed (Sensitivity 80%, Specificity 56%).

Figure 1.

Factors independently associated with preclinical ILD after 13 years of RA duration

Conclusion:

In this cross-sectional study of the prospective ESPOIR cohort, we identified clinical and genetic predictors for ILD after 13 years of RA duration. We developed a predictive score that could improve risk stratification for preclinical RA-ILD and help physicians identify patients with RA in whom a HRCT scan should be performed.

Disclosure of Interests:

Pierre-Antoine Juge Consultant of: BMS, Benjamin Granger: None declared, Marie-Pierre Debray: None declared, Esther Ebstein: None declared, Fabienne Louis Sidney: None declared, Joanna KEDRA: None declared, Raphael Borie: None declared, Arnaud Constantin Consultant of: Bristol-Meyers Squibb, Chugai, Roche, Abbvie, MSD, Pfizer, and UCB, Bernard Combe Consultant of: Abbvie, Bristol-Meyers Squibb, Lilly, MSD, Janssen, Pfizer, Roche, Chigai, and Sanofi, Grant/research support from: Abbvie, Bristol-Meyers Squibb, Lilly, MSD, Janssen, Pfizer, Roche, Chugai, and Sanofi, René-Marc Flipo Consultant of: Bristol-Meyers Squibb, Roche, Chugai, Abbvie, and Pfizer, Grant/research support from: Roche, Chugai, Abbvie, and Pfizer, Xavier Mariette Consultant of: Bristol-Meyers Squibb, GSK, Janssen, Pfizer, and UCB, Olivier VITTECOQ Consultant of: Bristol Myers Squibb, Roche, Chugai, MSD, Novartis, Pfizer, Abbvie, and Lilly, Alain Saraux Consultant of: Roche, Chugai, and Bristol-Meyers Squibb, Grant/research support from: Roche, Chugai, and Bristol-Meyers Squibb, Guillermo CARVAJAL ALEGRIA: None declared, Jean Sibilia Consultant of: Roche, Chugai, Bristol-Meyers Squibb, UCB, GSK, LFB, Actelion, Pfizer, MSD, Novartis, Amgen, Hospira, AbbVie, Sandoz, Gilead, Lilly, Sanofi, Janssen, and Mylan, Francis Berenbaum Consultant of: Boehringer, Bone Therapeutics, Expanscience, Galapagos, Gilead, GSK, Elli Lilly, Merck Sereno, MSD, Nordic, Novartis, Pfizer, Regulaxis, Roche, Sandoz, Sanofi, Servier, UCB, Peptinov, TRB Chemedica, 4P Pharma, Caroline Kannengiesser: None declared, Catherine Boileau: None declared, Bruno Crestani Consultant of: Boehringer Ingelheim, Roche, Sanofi, Apellis, Astra-Zeneca, Grant/research support from: MedImmune, Boehringer Ingelheim, Bruno Fautrel Consultant of: AbbVie, Biogen, BMS, Celgene, Janssen, Lilly, Medac, MSD, NORDIC Pharma, Novartis, Pfizer, Roche, Sanofi-Aventis, SOBI, UCB, Grant/research support from: AbbVie, MSD, Pfizer, Philippe Dieudé: None declared

AB0205 A NOVEL METHOD FOR PREDICTING 1-YEAR RETENTION OF ABATACEPT USING MACHINE LEARNING TECHNIQUES: DIRECTIONALITY AND IMPORTANCE OF PREDICTORS

Background:

In the ACTION (NCT02109666) study, multivariable Cox proportional hazards regression models showed that the predictors of 1-year retention to abatacept treatment were: patient global pain assessment, country, reason for stopping last biologic, number of prior biologic treatments, abatacept monotherapy, RF/anti-cyclic citrullinated peptide (CCP) status, previous neoplasms, psychiatric disorders and cardiac disorders.1 Machine learning techniques, using the gradient-boosting model, subsequently identified additional predictors of abatacept retention in patients with moderate-to-severe RA enrolled in ACTION; however, the analysis did not show the directionality of the predictors.2

Objectives:

To improve the clinical interpretability of the machine learning model in terms of directionality and the importance of each variable in predicting retention.

Methods:

Previous analyses using the gradient-boosting model to identify predictors of abatacept retention at 1 year in the ACTION study have been described.2 This analysis used SHapley Additive exPlanations (SHAP), a mathematical framework, to show how a particular predictor value influences prediction in the context of all other predictors. Higher SHAP values indicate a higher likelihood of retention. The contribution of every variable in the model’s prediction (with the exception of country variables) was computed for each data point to capture individual variable impact. This enabled interpretation for level of importance and directionality at a patient level.

Results:

Using data from 2350 patients enrolled in ACTION (May 2008 to December 2013), the mean retention rate at 1 year was 59.3% (n=1393). Overall variable importance is shown in Figure 1. After removal of country variables, the top five baseline predictors of retention were: no previous corticosteroid use, ACR functional class II, ≥2 prior biologic treatments prior to abatacept initiation, abatacept monotherapy and HAQ-DI. In terms of directionality, no previous corticosteroid use, ≥2 prior biologic treatments prior to abatacept initiation, abatacept monotherapy and a higher HAQ-DI score at baseline were associated with a lower likelihood of retention; ACR functional class II was associated with a higher likelihood of retention.

Conclusion:

The gradient-boosting model previously identified predictors of abatacept retention from ACTION;2 the addition of SHAP in this analysis has provided information on the importance and directionality of those predictors. The most important predictor of abatacept retention was no previous corticosteroid use, which was associated with lower retention. The models and predictors identified could be further refined by using additional datasets from clinical trials. Machine learning offers an innovative and complementary approach to biostatistics and could be used to identify treatment response predictors at an individual patient level, leading to a more personalised treatment approach.

References:

[1]Alten R, et al. RMD Open 2017;3:e000538.

[2]Alten R, et al. Presented at the virtual ACR Convergence 2020; 5–9 November 2020. Poster number 1745.

Acknowledgements:

This study was supported by Bristol Myers Squibb. Professional medical writing and editorial assistance was provided by Claire Line, PhD, at Caudex and was funded by Bristol Myers Squibb.

Disclosure of Interests:

Rieke Alten Speakers bureau: AbbVie, Bristol Myers Squibb, Gilead, Janssen, Lilly, Pfizer, Consultant of: AbbVie, Bristol Myers Squibb, Gilead, Janssen, Lilly, Pfizer, Grant/research support from: AbbVie, Bristol Myers Squibb, Gilead, Janssen, Lilly, Pfizer, Claire Behar Shareholder of: I have not invested directly in pharmaceutical companies producing drugs/devices for use in rheumatology however I may have shares via the funds linked to my life insurance., Consultant of: Bristol Myers Squibb, Christine Boileau Consultant of: AstraZeneca, Bristol Myers Squibb, Nanobiotix, Pierre Merckaert Consultant of: Bristol Myers Squibb, Ebenezer Afari Consultant of: Bristol Myers Squibb, Virginie Vannier-Moreau Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Sean Connolly Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb, Aurelie Najm Speakers bureau: Bristol Myers Squibb, Consultant of: Bristol Myers Squibb, Pierre-Antoine Juge Consultant of: Bristol Myers Squibb, Angshu Rai Shareholder of: Amgen Inc, Consultant of: Amgen Inc, Employee of: Amgen Inc, Bristol Myers Squibb, Yedid Elbez Consultant of: Bristol Myers Squibb, Karissa Lozenski Shareholder of: Bristol Myers Squibb, Employee of: Bristol Myers Squibb

A new KIF5B-ERBB4 gene fusion in a lung adenocarcinoma patient

ERBB4 fusion is a rare, novel oncogenic event involved in the development of lung adenocarcinoma that is not routinely looked for, although ERBB4 fusion is a potential target for existing pan-ErbB tyrosine kinase and must be implemented in the laboratory https://bit.ly/3nYmGQ9.

Methotrexate and rheumatoid arthritis associated interstitial lung disease

QUESTION ADDRESSED BY THE STUDY

Methotrexate (MTX) is a key anchor drug for rheumatoid arthritis (RA) management. Fibrotic interstitial lung disease (ILD) is a common complication of RA. Whether MTX exposure increases the risk of ILD in patients with RA is disputed. We aimed to evaluate the association of prior MTX use with development of RA-ILD.

METHODS

Through a case-control study design with discovery and international replication samples, we examined the association of MTX exposure with ILD in 410 patients with chronic fibrotic ILD associated with RA (RA-ILD) and 673 patients with RA without ILD. Estimates were pooled over the different samples using meta-analysis techniques.

RESULTS

Analysis of the discovery sample revealed an inverse relationship between MTX exposure and RA-ILD (adjusted OR 0.46, 95% CI 0.24-0.90; p=0.022), which was confirmed in the replication samples (pooled adjusted OR 0.39, 95% CI 0.19-0.79; p=0.009). The combined estimate using both the derivation and validation samples revealed an adjusted OR of 0.43 (95% CI 0.26-0.69; p=0.0006). MTX ever-users were less frequent among patients with RA-ILD compared to those without ILD, irrespective of chest high-resolution computed tomography pattern. In patients with RA-ILD, ILD detection was significantly delayed in MTX ever-users compared to never-users (11.4±10.4 years and 4.0±7.4 years, respectively; p<0.001).

ANSWER TO THE QUESTION

Our results suggest that MTX use is not associated with an increased risk of RA-ILD in patients with RA, and that ILD was detected later in MTX-treated patients.

Pathogenic FBN1 Genetic Variation and Aortic Dissection in Patients With Marfan Syndrome

BACKGROUND

Aortic risk has not been evaluated in patients with Marfan syndrome and documented pathogenic variants in the FBN1 gene.

OBJECTIVES

This study sought to describe aortic risk in a population with Marfan syndrome with pathogenic variants in the FBN1 gene as a function of aortic root diameter.

METHODS

Patients carrying an FBN1 pathogenic variant who visited our reference center at least twice were included, provided they had not undergone aortic surgery or had an aortic dissection before their first visit. Aortic events (aortic surgery or aortic dissection) and deaths were evaluated during the 2 years following each patient visit. The risk was calculated as the number of events divided by the number of years of follow-up.

RESULTS

A total of 954 patients were included (54% women; mean age 23 years). During follow-up (9.1 years), 142 patients underwent prophylactic aortic root surgery, 5 experienced type A aortic dissection, and 12 died (noncardiovascular causes in 3, unknown etiology in 3, post-operative in 6). When aortic root diameter was <50 mm, risk for proven type A dissection (0.4 events/1,000 patient-years) and risk for possible aortic dissection (proven aortic dissection plus death of unknown cause, 0.7 events/1,000 patients-years) remained low in this population that was treated according to guidelines. Three type A aortic dissections occurred in this population during the 8,594 years of follow-up, including 1 in a patient with a tubular aortic diameter of 50 mm, but none in patients with a family history of aortic dissection. The risk for type B aortic dissection in the same population was 0.5 events/1,000 patient-years.

CONCLUSIONS

In patients with FBN1 pathogenic variants who receive beta-blocker therapy and who limit strenuous exercise, aortic risk remains low when maximal aortic diameter is <50 mm. The risk of type B aortic dissection is close to the remaining risk of type A aortic dissection in this population, which underlines the global aortic risk.

Electrocardiographic and echocardiographic abnormalities associated with mitral valve prolapse in patients with Marfan syndrome

Introduction

Marfan syndrome (MFS) is responsible for cardiovascular disorders such as aortic aneurism and mitral valve prolapse (MVP).

A malignant MVP phenotype combining clinical, electrical and morphological features has been described in symptomatic patients who have experienced sudden cardiac death or complex ventricular arrhythmias.

We have taken advantage of the high prevalence of MVP in MFS patient to study the clinical, electrical and echocardiographic abnormalities associated with MVP.

Purpose

The aim of this study is to describe the clinical, electrical and morphological cardiac abnormalities associated with MVP in a cohort of MFS patients with FBN1 mutations with a high prevalence of MVP and who did not suffer from severe ventricular arrhythmias.

Methods

All consecutive patients coming to the National Reference Center for Marfan syndrome were evaluated prospectively i.e. clinical examination, 12-lead electrocardiogram, standard transthoracic echocardiography study and molecular genetic screening.

Results

352 consecutive patients were included from April 2015 to October 2016 [250 FBN1 mutation carriers (MFS) and 102 healthy relatives (HR)]. None of the patients had a history of sudden cardiac death or complex ventricular arrhythmia.

MFS vs HR: MFS patients were younger (33 vs 41yo p&lt;0.001) and 2/3 were women in both groups. In the MFS group, abnormal T waves repolarization in lateral leads were more common [172 MFS (70.2%) vs. 87 HR (86.14%) p&lt;0,0012], as was MVP [38.37% vs 1.96%; p&lt;0,0001], and diastolic hypertrophy of the basal segment of the inferolateral wall (thickness &gt;11mm) [22.31% vs. 9.18%; p&lt;0.0001].

In MFS, MVP affected either one valve (21.22%), or both (17.14%), and was not associated with electric abnormalities. However, diastolic basal inferolateral wall hypertrophy was associated with mitral valve prolapse (p&lt;0,0001), QTc interval prolongation (p&lt;0.0229), abnormal T waves repolarization in the inferior leads (p=0.004), and higher aortic Z-Score (p=0.274).

Conclusion

In MFS patients, the prevalence of MVP is high and no significant association between MVP and electrical abnormalities was found. In contrast, basal inferolateral wall hypertrophy is associated with MVP and repolarization disorders in inferior leads and QTc interval prolongation, i.e, electrocardiographic abnormalities described in malignant MVP.

QTc and basal inferolateral hypertrophy

Funding Acknowledgement

Type of funding source: None

Pathogenic variants in THSD4, encoding the ADAMTS-like 6 protein, predispose to inherited thoracic aortic aneurysm

Purpose:

Thoracic aortic aneurysm and dissection (TAAD) is a life-threatening disease with often unrecognized inherited forms. We sought to identify novel pathogenic variants associated with autosomal dominant inheritance of TAAD.

Methods:

We analyzed exome sequencing data from 35 French TAAD families and performed next-generation sequencing capture panel of genes in 1114 unrelated TAAD patients. Functional effects of pathogenic variants identified were validated in cell, tissue, and mouse models.

Results:

We identified five functional variants in THSD4 of which two heterozygous variants lead to a premature termination codon. THSD4 encodes ADAMTSL6 (member of the ADAMTS/L superfamily), a microfibril-associated protein that promotes fibrillin-1 matrix assembly. The THSD4 variants studied lead to haploinsufficiency or impaired assembly of fibrillin-1 microfibrils. Thsd4^+/− mice showed progressive dilation of the thoracic aorta. Histologic examination of aortic samples from a patient carrying a THSD4 variant and from Thsd4^+/− mice, revealed typical medial degeneration and diffuse disruption of extracellular matrix.

Conclusion:

These findings highlight the role of ADAMTSL6 in aortic physiology and TAAD pathogenesis. They will improve TAAD management and help develop new targeted therapies.

Quantifying the Genetic Basis of Marfan Syndrome Clinical Variability

Marfan syndrome (MFS) is an autosomal dominant connective tissue disorder with considerable inter- and intra-familial clinical variability. The contribution of inherited modifiers to variability has not been quantified. We analyzed the distribution of 23 clinical features in 1306 well-phenotyped MFS patients carrying FBN1 mutations. We found strong correlations between features within the same system (i.e., ophthalmology vs. skeletal vs. cardiovascular) suggesting common underlying determinants, while features belonging to different systems were largely uncorrelated. We adapted a classical quantitative genetics model to estimate the heritability of each clinical feature from phenotypic correlations between relatives. Most clinical features showed strong familial aggregation and high heritability. We found a significant contribution by the major locus on the phenotypic variance only for ectopia lentis using a new strategy. Finally, we found evidence for the “Carter effect” in the MFS cardiovascular phenotype, which supports a polygenic model for MFS cardiovascular variability and indicates additional risk for children of MFS mothers with an aortic event. Our results demonstrate that an important part of the phenotypic variability in MFS is under the control of inherited modifiers, widely shared between features within the same system, but not among different systems. Further research must be performed to identify genetic modifiers of MFS severity.

Excess of de novo variants in genes involved in chromatin remodelling in patients with marfanoid habitus and intellectual disability

PURPOSE

Marfanoid habitus (MH) combined with intellectual disability (ID) (MHID) is a clinically and genetically heterogeneous presentation. The combination of array CGH and targeted sequencing of genes responsible for Marfan or Lujan-Fryns syndrome explain no more than 20% of subjects.

METHODS

To further decipher the genetic basis of MHID, we performed exome sequencing on a combination of trio-based (33 subjects) or single probands (31 subjects), of which 61 were sporadic.

RESULTS

We identified eight genes with de novo variants (DNVs) in at least two unrelated individuals (ARID1B, ATP1A1, DLG4, EHMT1, NFIX, NSD1, NUP205 and ZEB2). Using simulation models, we showed that five genes (DLG4, NFIX, EHMT1, ZEB2 and ATP1A1) met conservative Bonferroni genomewide significance for an excess of the observed de novo point variants. Overall, at least one pathogenic or likely pathogenic variant was identified in 54.7% of subjects (35/64). These variants fell within 27 genes previously associated with Mendelian disorders, including NSD1 and NFIX, which are known to be mutated in overgrowth syndromes.

CONCLUSION

We demonstrated that DNVs were enriched in chromatin remodelling (p=2×10^-4) and genes regulated by the fragile X mental retardation protein (p=3×10^-8), highlighting overlapping genetic mechanisms between MHID and related neurodevelopmental disorders.

Is there an agreement between self-reported medical diagnosis in the CARTaGENE cohort and the Québec administrative health databases?

BACKGROUND

Population health studies often use existing databases that are not necessarily constituted for research purposes. The question arises as to whether different data sources such as in administrative health data (AHD) and self-report questionnaires are equivalent and lead to similar information.

OBJECTIVES

The main objective of this study was to assess the level of agreement between self-reported medical conditions and medical diagnosis captured in AHD. A secondary objective was to identify predictors of agreement among medical conditions between the two data sources. Therefore, the purposes of the study were to explore the extent to which these two methods of commonly used public health data collection provide concordant records and identify the main predictors of statistical variations.

METHODS

Data were extracted from CARTaGENE, a population-based cohort in Québec, Canada, which was linked to the provincial health insurance records of the same individuals, namely the MED-ÉCHO database from the Régie de l'assurance maladie du Québec (RAMQ) and the fee-for-service billing records provided by the physician, for the time period 1998-2012. Agreement statistics (kappa coefficient) along with sensitivity, specificity and predictive positive value were calculated for 19 chronic conditions and 12 types of cancers. Logistic regressions were used to identify predictors of concordance between self-report and AHD from significant covariates (sex, age groups, education, region, income, heavy utilization of health care system and Charlson comorbidity index).

RESULTS

Agreement between self-reported data and AHD across diseases ranged from kappa of 0.09 for chronic renal failure to 0.86 for type 2 diabetes. Sensitivity of self-reported data was higher than 50% for 14 out of the 31 medical conditions studied, especially for myocardial infarction (88.62%), breast cancer (86.28%), and diabetes (85.06%). Specificity was generally high with a minimum value of 89.70%. Lower concordance between data sources was observed for higher frequency of health care utilization and higher comorbidity scores.

CONCLUSION

Overall, there was moderate agreement between the two data sources but important variations were found depending on the type of disease. This suggests that CARTaGENE's participants were generally able to correctly identify the kind of diseases they suffer from, with some exceptions. These results may help researchers choose adequate data sources according to specific study objectives. These results also suggest that Québec's AHD seem to underestimate the prevalence of some chronic conditions, which might result in inaccurate estimates of morbidity with consequences for public health surveillance.

A Case of Trisomy 13 Mosaicism Presenting with a Severe Aortic Root Dilatation and Marfanoid Habitus due to an Unpredictable Cytogenetic Mechanism

In this report, we present a new case of mosaic trisomy 13 with prolonged survival, firstly detected by array-CGH analysis which was carried out because of moderate intellectual disability with postaxial hexadactyly, dermatologic features, ventricular septal defect, bicuspid aortic valve, and aortic dystrophy in a 19-year-old male patient. In a subset of 15% of the cells, the patient carried a derivative chromosome 10 generated by a nonreciprocal (10;13) translocation inherited from his healthy mother who carried the translocation in a balanced and homogeneous state. FISH analyses showed interstitial telomeric sequences at the breakpoints. To our knowledge, this is the second report of a patient with trisomy 13 mosaicism displaying a severe aortic root dilatation. We also discuss the mechanisms which could explain the mosaic state, the most likely one being related to the instability of the interstitial telomere.

Clinical and genetic data of 22 new patients with SMAD3 pathogenic variants and review of the literature

Background

Pathogenic SMAD3 variants are responsible for a cardiovascular phenotype, mainly thoracic aortic aneurysms and dissections. Precocious identification of the vascular risk such as aortic dilatation in mutated patients has a major impact in terms of management, particularly to avoid dissection and sudden death. These vascular damages are classically associated with premature osteoarthritis and skeletal abnormalities. However, variable expressivity and incomplete penetrance are common with SMAD3 variants.

Methods

To investigate the clinical variability observed within SMAD3 patients, we reviewed the phenotypic and genetic data of 22 new patients from our Centre and of 133 patients reported in the literature. From this cohort of 155 mutated individuals, we first aimed to delineate an estimated frequency of the main clinical signs associated with SMAD3 pathogenic variants and, then, to look for genotype‐phenotype correlations, mainly to see if the aortic phenotype (AP) could be predicted by the SMAD3 variant type.

Results

We showed, herein, the absence of correlation between the SMAD3 variant type and the occurrence of an AP in patients.

Conclusion

Therefore, this report brings additional data for the genotype‐phenotype correlations of SMAD3 variants and the need to explore in more detail the effects of genetic modifiers that could influence the phenotype.