Januszewicz, Andrzej

Abstract Hereditary tumor predisposition syndromes pose a challenge for early detection and timely treatment of tumors. In von Hippel–Lindau disease, desirable personalized surveillance programs are lacking due to insufficient data on genotype-specific risk profiles of individual mutations. To describe neoplastic risk profiles for carriers of pathogenic and likely pathogenic VHL germline mutations, our observational study recruited 1,350 participants from 40 centers worldwide. 432 different VHL germline mutations were observed, with p.Asn78Ser, p.Arg161Ter, p.Arg161Gln, p.Arg167Gln, p.Arg167Trp and p.Tyr98His being the six most frequent, occurring in a total of 493 carriers (36.5%) and in ≥30 patients each. Age-related penetrance risks for retinal hemangioblastoma, central nervous system hemangioblastoma, renal cell carcinoma, pancreatic neuroendocrine tumors and pheochromocytoma/paraganglioma in carriers of the most frequent VHL mutations were assessed. In addition, the number of organs affected, the frequency of surgery and the outcome are reported. Pairwise comparisons of the age-dependent tumor penetrance of these six mutations showed that 47 out of 90 pairs were significantly different. The most significant associations were found in p.Tyr98His (n = 19), followed by p.Arg161Ter (n = 10). All pairwise comparisons of mutations affecting different codons showed at least one significant (P < 0.05) difference, except for p.Asn78Ser vs p.Arg161Ter. Thus, tumor risk varied by VHL mutation type and location, but did not differ between the truncating mutation p.Arg161Ter and the missense mutation p.Asn78Ser. Our study demonstrates the importance of mutation-specific phenotype prediction. With appropriate validation, the data have important implications for risk assessment and decision making in tumor prevention for carriers of the respective VHL mutations.

Introduction: Fibromuscular dysplasia (FMD) is a non-atherosclerotic arteriopathy of unknown etiology, afflicting mostly middle-aged women. It is characterized by stenotic lesions of the vascular wall in middle-size arteries, sometimes associated with dissection, aneurysm or tortuosity. Renovascular hypertension is a major presentation of FMD and 50–85% of FMD patients are hypertensive. Methods & Results: We report results from the first genome-wide association meta-analysis of six studies including 1556 FMD cases and 7100 controls. We identified four robustly associated loci (PHACTR1, LRP1, ATP2B1, and LIMA1). Using colocalization and transcriptome-wide association analysis with arterial expression datasets, we found PHACTR1, LRP1 and ATP2B1 as target genes at FMD loci and identified one additional locus (SLC24A3). We analysed chromatin accessibility in artery-derived primary cells and found that FMD associated variants were located in arterial specific regulatory elements active in smooth muscle cells. Target genes were broadly involved in mechanisms related to actin cytoskeleton and intracellular calcium homeostasis, central to vascular contraction. All FMD loci were also associated to at least one blood pressure trait. Colocalization analysis supported the same genetic variants to cause association to FMD and systolic blood pressure at PHACTR1, ATP2B1 and LIMA1 loci, and for FMD and pulse pressure at PHACTR1, LRP1 and ATP2B1 loci. Using genome-wide genetic correlation, we found a significant association between FMD and blood pressure. Mendelian Randomization analysis supported genetically determined systolic blood pressure to significantly increase the risk of FMD. However, we confirmed using adjusted and stratified analyses that hypertension status alone was not driving the association with FMD at top loci. We also report an important genetic overlap of FMD with migraine, intracranial aneurysm, coronary artery disease and myocardial infarction. Conclusion: Our study confirms FMD as a polygenic disease following a complex genetic mode of inheritance. We find that FMD shares an important part of its genetic basis with blood pressure regulation, involving in particular several genes related to intracellular calcium homeostasis and vascular smooth muscle contraction. These results are consistent with previous studies showing systemic alterations in vascular contraction in FMD patients, even outside of affected arterial beds. While the mechanisms through which FMD may cause renovascular hypertension are well known, further studies will be required to determine how alterations in vascular contraction may lead to the arterial remodeling observed in FMD.

Abstract Objective: Fibromuscular dysplasia (FMD) is an arteriopathy that presents mainly by hypertension, stroke or dissection. Diagnosis is often made in middle-aged women with few cardiovascular risk factors. We aim at identifying common genetic variants associated to FMD. Design and method: We tested ∼6.5 million common genetic variants (MAF > 0.01) in 1962 cases and 7100 controls from 6 studies using variants and gene-based association analyses. Participants were of European ancestry, with similar characteristics (91% multifocal, 88% women), diagnosis methods and inclusion/exclusion criteria. Transcriptome-wide association (TWAS), eQTL, gene expression by sex and colocalization analyses used expression data in arteries from GTEx and/or FMD patients and matched controls. Open chromatin regions were defined using ATAC-Seq on primary human fibroblasts, smooth muscle and endothelial cells. Genetic correlations were assessed using summary statistics from UKBiobank and/or published studies by linkage disequilibrium score regression and multi-trait-based conditional and joint analyses (mtCOJO). Results: We confirmed the previously identified PHACTR1 locus and identified three new loci (LRP1, ATP2B1, and LIMA1) associated with FMD. TWAS in arteries identified one additional locus (SLC24A3). Through integration of annotation datasets, we provided prioritization of variants and genes. These are consistently and specifically expressed in fibroblasts, smooth muscle cells, and arterial tissues. PHACTR1 and SLC24A3 showed sex differences in gene expressions consistent with the direction of effects of FMD risk alleles. FMD genes are involved in regulatory mechanisms related to actin cytoskeleton and intracellular calcium homeostasis, two mechanisms central to vascular contraction. We found significant genetic overlaps between FMD and blood pressure traits, for the associated loci and globally at the genome level, but demonstrated that hypertension is not driving the genetic association with FMD. We also found positive genetic correlations with migraine and intracranial aneurysm, and an inverse correlation with coronary artery disease, independently from the genetics of blood pressure. Conclusions: We describe robustly associated loci and genes with FMD and provide several new leads toward understanding biological mechanisms of stenosis and dissection in young women in the absence of atherosclerosis, which shares part of its genetic basis with more common cardiovascular and neurovascular diseases.

It has been postulated that catheter-based renal denervation (RDN) may lower blood pressure (BP) and improve severity of obstructive sleep apnea (OSA) in resistant hypertensive patients. The aim of our study (NCT01366625) was to investigate in a prospective randomized trial the effect of RDN on BP and clinical course of OSA. Sixty patients with true resistant hypertension coexisting with moderate-to-severe OSA (apnea/hypopnea index, ≥15) were randomly allocated to RDN group (30 patients) and to control group (30 patients). The primary end point was reduction in office systolic BP at 3 months. Secondary end points included reduction in diastolic office and ambulatory BP, change in apnea/hypopnea index and biochemical measurements at 3 months, and change in echocardiographic measurements at 6 months. There were no differences in clinical characteristics between the groups. At 3 months in the RDN group, both office and ambulatory BP were significantly reduced, and a significant decrease in OSA severity (apnea/hypopnea index, 39.4 versus 31.2 events per hour; P =0.015) was observed. Between-group difference in apnea/hypopnea index change was significant at 0.05. At 6 months in the RDN group, reductions in office and ambulatory BP were sustained and were accompanied by significant improvement in echocardiographic measures of global longitudinal strain. There were no differences in metabolic variables in follow-up in both groups. In a randomized controlled trial, RDN lowered both office and ambulatory BP in patients with resistant hypertension and OSA. This was accompanied by improvement of the clinical severity of OSA. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT01366625.