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Background The treatment, genotyping, and phenotyping of patients with World Health Organization Group 1 pulmonary arterial hypertension (PAH) have evolved dramatically in the last decade. Research Question The United States Pulmonary Hypertension Scientific Registry was established as the first US PAH patient registry to investigate genetic information, reproductive histories, and environmental exposure data in a contemporary patient population. Study Design and Methods Investigators at 15 US centers enrolled consecutively screened adults diagnosed with Group 1 PAH who had enrolled in the National Biological Sample and Data Repository for PAH (PAH Biobank) within 5 years of a cardiac catheterization demonstrating qualifying hemodynamic criteria. Exposure and reproductive histories were collected by using a structured interview and questionnaire. The biobank provided genetic data. Results Between 2015 and 2018, a total of 499 of 979 eligible patients with clinical diagnoses of idiopathic PAH (IPAH) or familial PAH (n = 240 [48%]), associated PAH (APAH; n = 256 [51%]), or pulmonary venoocclusive disease/pulmonary capillary hemangiomatosis (n = 3 [1%]) enrolled. The mean age was 55.8 years, average BMI was 29.2 kg/m2, and 79% were women. Mean duration between symptom onset and diagnostic catheterization was 1.9 years. Sixty-six percent of patients were treated with more than one PAH medication at enrollment. Past use of prescription weight loss drugs (16%), recreational drugs (27%), and oral contraceptive pills (77%) was common. Women often reported miscarriage (37%), although PAH was rarely diagnosed within 6 months of pregnancy (1.9%). Results of genetic testing identified pathogenic or suspected pathogenic variants in 13% of patients, reclassifying 18% of IPAH patients and 5% of APAH patients to heritable PAH. Interpretation Patients with Group 1 PAH remain predominately middle-aged women diagnosed with IPAH or APAH. Delays in diagnosis of PAH persist. Treatment with combinations of PAH-targeted medications is more common than in the past. Women often report pregnancy complications, as well as exposure to anorexigens, oral contraceptives, and/or recreational drugs. Results of genetic tests frequently identify unsuspected heritable PAH.

Background Insulin-like growth factors (IGFs), and their binding proteins (IGFBPs), play a significant role in cardiovascular function and may influence the pathobiology of PAH. We determined the diagnostic and prognostic value of IGF1 and IGFBP2 in pediatric PAH. Methods Serum was analyzed by ELISA for IGF1 and IGFBP2 in pediatric PAH subjects from the NHLBI PAH Biobank (PAHB, n = 175) and a cohort of asthmatic subjects (n = 46, age 0-21 years) as a chronic pediatric pulmonary disease control. Biomarkers were analyzed with demographic and clinical variables for PAH severity. Results Serum IGF1 was significantly lower in PAH compared to controls, while IGFBP2 was elevated in PAH subjects compared to controls. In the PAHB, IGF1 was negatively associated with mPAP and PVR, while IGFBP2 was positively associated with PVR and negatively associated with cardiac output and 6-min walk distance. Higher IGFBP2 levels were associated with use of prostacyclin therapy. IGFBP2 was associated with death, transplant, or palliative shunt with a Cox proportional hazard ratio of 8.8 (p Conclusions Circulating IGFBP2 is a novel marker for pediatric PAH, which is associated with worse functional status, and survival. IGF axis dysregulation may be an important mechanistic target in pediatric pulmonary arterial hypertension. Impact Pediatric pulmonary hypertension is a severe disease, with poorly understood pathobiology.There are few studies looking at the pathobiology of pulmonary hypertension only in children.The IGF axis is dysregulated in pediatric pulmonary arterial hypertension.IGF axis dysregulation, with increased IGFBP2, is associated with worse clinical outcomes in pediatric pulmonary artery hypertension.IGF axis dysregulation gives new insight into the disease process and may be a mechanistic or therapeutic target.Fig. 1IGF1 AND IGFBP2 CONCENTRATION (NG/ML) IN PAH BIOBANK VERSUS CONTROLS.: a IGF1 concentration (ng/mL) in PAH Biobank versus asthmatic subjects. b IGFBP2 concentration (ng/mL) in PAH Biobank versus asthmatic subjects.Fig. 2ROC CURVE OF IGF1 AND IGFBP2 IN PAH BIOBANK VERSUS CONTROLS.: a ROC curve of IGF1 in PAH Biobank subjects versus controls. AUC 0.82. Cut point for IGF1 of 177 ng/mL gives a sensitivity of 73.9% and a specificity of 78.3%. b ROC curve of IGFBP2 in PAH Biobank subjects versus controls. AUC 0.80. Cut point for IGFBP2 of 185 ng/mL gives a sensitivity of 72.2% and a specificity of 80.4%.Fig. 3IGFBP2 CONCENTRATIONS IN PAH SUBJECTS BY MEDICATION COMBINATION.: a IGFBP2 concentration in PAH subjects on a PDE5 inhibitor, a PDE5 inhibitor and an ERA, a PDE5 inhibitor and IV/SQ PCA, or a combination of PDE5 inhibitor, ERA, and IV/SQ PCA. b IGFBP2 concentrations in PAH subjects on an IV/SQ PCA and any other therapy versus subject not on IV/SQ PCA and any other therapy.Fig. 4Kaplan-Meier curve showing time to death, transplant, or palliative shunt (Pott's shunt or atrial septostomy) dichotomized by the median IGFBP2 level.

BACKGROUND: Three biomarkers, soluble suppression of tumorigenicity 2 (ST2), galectin 3 (Gal3), and N-terminal brain natriuretic peptide prohormone (NT-proBNP), are approved for noninvasive risk assessment in left-sided heart failure, and small observational studies have shown their prognostic usefulness in heterogeneous pulmonary hypertension cohorts. We examined associations between these biomarkers and disease severity and survival in a large cohort of patients with pulmonary arterial hypertension (PAH) (ie, group 1 pulmonary hypertension). We hypothesized that additive use of biomarkers in combination would improve the prognostic value of survival models. METHODS: Biomarker measurements and clinical data were obtained from 2,017 adults with group 1 PAH. Associations among biomarker levels and clinical variables, including survival times, were examined with multivariable regression models. Likelihood ratio tests and the Akaike information criterion were used to compare survival models. RESULTS: Higher ST2 and NT-proBNP were associated with higher pulmonary pressures and vascular resistance and lower 6-min walk distance. Higher ST2 and NT-proBNP levels were associated with increased risk of death (hazard ratios: 2.79; 95% CI, 2.21-3.53; P < .001 and 1.84; 95% CI, 1.62-2.10; P < .001, respectively). The addition of ST2 to survival models composed of other predictors of survival, including NT-proBNP, significantly improved model fit and predictive capacity. CONCLUSIONS: ST2 and NT-proBNP are strong, noninvasive prognostic biomarkers in PAH. Despite its prognostic value in left-sided heart failure, Gal3 was not predictive in PAH. Adding ST2 to survival models significantly improves model predictive capacity. Future studies are needed to develop multimarker assays that improve noninvasive risk stratification in PAH.

BackgroundInflammation and dysregulated immunity are important in the development of pulmonary arterial hypertension (PAH). Compelling preclinical data supports the therapeutic blockade of interleukin-6 (IL-6) signalling.MethodsWe conducted a phase 2 open-label study of intravenous tocilizumab (8 mg·kg−1) over 6 months in patients with group 1 PAH. Co-primary end-points were safety, defined by incidence and severity of adverse events, and change in pulmonary vascular resistance. Separately, a mendelian randomisation study was undertaken on 11 744 individuals with European ancestry including 2085 patients with idiopathic/heritable disease for the IL-6 receptor (IL6R) variant (rs7529229), known to associate with circulating IL-6R levels.ResultsWe recruited 29 patients (male/female 10/19; mean±sd age 54.9±11.4 years). Of these, 19 had heritable/idiopathic PAH and 10 had connective tissue disease-associated PAH. Six were withdrawn prior to drug administration; 23 patients received at least one dose of tocilizumab. Tocilizumab was discontinued in four patients owing to serious adverse events. There were no deaths. Despite evidence of target engagement in plasma IL-6 and C-reactive protein levels, both intention-to-treat and modified intention-to-treat analyses demonstrated no change in pulmonary vascular resistance. Inflammatory markers did not predict treatment response. Mendelian randomisation did not support an effect of the lead IL6R variant on risk of PAH (OR 0.99, p=0.88).ConclusionAdverse events were consistent with the known safety profile of tocilizumab. Tocilizumab did not show any consistent treatment effect.

Background Endostatin, an angiogenic inhibitor, is associated with worse pulmonary arterial hypertension (PAH) outcomes in adults and poor lung growth in children. This study sought to assess whether endostatin is associated with disease severity and outcomes in pediatric PAH. Methods and Results Serum endostatin was measured in cross‐sectional (N=160) and longitudinal cohorts (N=64) of pediatric subjects with PAH, healthy pediatric controls and pediatric controls with congenital heart disease (CHD) (N=54, N=15), and adults with CHD associated PAH (APAH‐CHD, N=185). Outcomes, assessed by regression and Kaplan‐Meier analysis, included hemodynamics, change in endostatin over time, and transplant‐free survival. Endostatin secretion was evaluated in pulmonary artery endothelial and smooth muscle cells. Endostatin was higher in those with PAH compared with healthy controls and controls with CHD and was highest in those with APAH‐CHD. In APAH‐CHD, endostatin was associated with a shorter 6‐minute walk distance and increased mean right atrial pressure. Over time, endostatin was associated with higher pulmonary artery pressure and pulmonary vascular resistance index, right ventricular dilation, and dysfunction. Endostatin decreased with improved hemodynamics over time. Endostatin was associated with worse transplant‐free survival. Addition of endostatin to an NT‐proBNP (N‐terminal pro‐B‐type natriuretic peptide) based survival analysis improved risk stratification, reclassifying subjects with adverse outcomes. Endostatin was secreted primarily by pulmonary artery endothelial cells. Conclusions Endostatin is associated with disease severity, disease improvement, and worse survival in APAH‐CHD. Endostatin with NT‐proBNP improves risk stratification, better predicting adverse outcomes. The association of elevated endostatin with shunt lesions suggests that endostatin could be driven by both pulmonary artery flow and pressure. Endostatin could be studied as a noninvasive prognostic marker, particularly in APAH‐CHD.

Introduction: Up to 27% of individuals undergoing subthalamic nucleus deep brain stimulation (STN-DBS) have a genetic form of Parkinson's disease (PD). Glucocerebrosidase (GBA) mutation carriers, compared to sporadic PD, present with a more aggressive disease, less asymmetry, and fare worse on cognitive outcomes with STN-DBS. Evaluating STN intra-operative local field potentials provide the opportunity to assess and compare symmetry between GBA and non-GBA mutation carriers with PD; thus, providing insight into genotype and STN physiology, and eligibility for and programming of STN-DBS. The purpose of this pilot study was to test differences in left and right STN resting state beta power in non-GBA and GBA mutation carriers with PD.Materials and Methods: STN (left and right) resting state local field potentials were recorded intraoperatively from 4 GBA and 5 non-GBA patients with PD while off medication. Peak beta power expressed as a ratio to total beta power (peak beta ratio) was compared between STN hemispheres and groups while co-varying for age, age of disease onset, and disease severity.Results: Peak beta ratio was significantly different between the left and the right STN for the GBA group (p < 0.01) but not the non-GBA group (p = 0.56) after co-varying for age, age of disease onset, and disease severity.Discussion: Peak beta ratio in GBA mutation carriers was more asymmetric compared with non-mutation carriers and this corresponded with the degree of clinical asymmetry as measured by rating scales. This finding suggests that GBA mutation carriers have a physiologic signature that is distinct from that found in sporadic PD.

Diagnostic World Health Organization (WHO) Group 1 pulmonary arterial hypertension (PAH) and Diagnostic Group 1' pulmonary veno-occlusive disease (PVOD) and/or pulmonary capillary hemangiomatosis (PCH) are progressive and fatal disorders. Past registries provided important insights into these disorders, but did not include hormonal exposures or genomic data. The United States Pulmonary Hypertension Scientific Registry (USPHSR) will provide demographic, physiologic, anorexigen and hormone exposure, genomic, and survival data in the current therapeutic era for 499 patients diagnosed with PAH, PVOD, or PCH. The USPHSR also will explore the relationship between pharmacologic, non-pharmacologic, and dietary hormonal exposures and the increased risk for women to develop idiopathic or heritable PAH.

BACKGROUND: Pediatric pulmonary hypertension is a severe disease defined by sustained elevation of pulmonary artery pressures and pulmonary vascular resistance (PVR). Noninvasive diagnostic and prognostic markers that are more pulmonary vascular specific have been elusive because of disease heterogeneity and patient growth. RESEARCH QUESTION: Is soluble suppressor of tumorigenicity (ST2) associated with pulmonary hemodynamic and functional changes in pediatric pulmonary hypertension? Does ST2 improve mortality risk models in pediatric pulmonary hypertension? STUDY DESIGN AND METHODS: Two pediatric cohorts (age < 21 years) were assayed for ST2 and N-terminal prohormone B-natriuretic peptide: a cross-sectional cohort from the National Heart Lung and Blood Institute-funded National Biological Sample and Data Repository for PAH (PAHB) (N = 182), and a second longitudinal cohort from Children’s Hospital of Colorado (N = 61). Adjusted linear regression was used for association with clinical variables. Clinical mortality models (the Registry to Evaluate Early and Long-Term PAH Disease Management [REVEAL] score) with and without ST2 were used to predict worsening outcomes and compared. Pulmonary artery endothelial and smooth muscle cell ST2 expression and secretion were assayed in vitro. RESULTS: In an adjusted (age and sex) analysis in the PAHB, ST2 was significantly associated with shorter 6-min walk distance (P = .03) and increased PVR index (P = .02). In adjusted longitudinal regression in the Children’s Hospital of Colorado cohort, ST2 was significantly associated with higher PVR index (P < .001), shorter 6-min walk distance (P = .01), and higher mean pulmonary artery pressure (P < .001). Although the REVEAL Risk Score Calculator 2.0 was predictive of clinical worsening in the PAHB (hazard ratio, 1.88), addition of ST2 significantly improved the model (hazard ratio, 2.05). In cell culture, ST2 was produced and secreted predominately by endothelial cells as opposed to smooth muscle cells (P < .0001). INTERPRETATION: In two pediatric PAH cohorts, elevated ST2 was associated with unfavorable pulmonary hemodynamics and functional measures, clinical worsening, and significantly improved prediction of clinical worsening. Pulmonary artery endothelial cellular expression of ST2 suggests that ST2 is a more pulmonary vascular-specific marker for pulmonary hypertension.

Introduction: Pediatric pulmonary arterial hypertension (PAH) is a multifactorial pulmonary vascular disease with high mortality. Endostatin (ES), an angiogenic inhibitor, is associated with disease severity and mortality in adults with PAH and poor lung growth in children. Hypothesis: Increased ES is associated with worse disease severity and outcomes in pediatric PAH. Methods: Serum ES levels were measured in two cohorts of pediatric PAH (IPAH, FPAH and APAH) patients; the cross-sectional CCHMC PAH Biobank (PAHB, N=175) and a longitudinal cohort from Children’s Hospital of Colorado (CHC, N=61). Outcomes included medical therapy, functional and hemodynamic measures, and survival (death, transplant, palliative shunt). Adjusted logistic and linear regressions and Kaplan-Meier analysis were used to assess the relationship between ES and clinical outcomes. Results: In both cohorts, ES was significantly higher in PAH associated with congenital heart disease (APAH-CHD, PAHB n=70, p=0.002; CHC n=29, p=0.007) and was highest in those with a ventricular shunt (n=24, p=0.001). In APAH-CHD, ES was associated with a decreased 6MWD (-108m, -187- -30, p=0.01) and increased mean right atrial pressure (mRAP 1.8mmHg, 0.3-3.3, p=0.02). Longitudinally, in the APAH-CHD subgroup when adjusted for age, sex, and multiple time points, higher ES was associated with increased PVRi and mPAP (PVRi 2.5WU*m 2 , 0.7-4.3, p=0.007; mPAP 10mmHg, 4.5-15, p Conclusions: ES was associated with worse functional measures, pulmonary vascular hemodynamics, and survival in pediatric APAH-CHD. These observations suggest that serum ES could act as a pulmonary vascular specific biomarker to identify those who are at increased risk of developing PAH and predict poor outcomes in APAH-CHD.

Background: Up to 25% of idiopathic and > 70% of cases with familial pulmonary arterial hypertension (PAH) can be explained by rare deleterious variants in established PAH risk genes. We hypothesised that integrating deep phenotyping with whole-genome sequencing (WGS) data will reveal additional disease variants that are ultra-rare and/or have a unique phenotypic signature. Methods: We analysed WGS data from 1,148 PAH patients and 11,889 controls enrolled in the NIHR BioResource-Rare Diseases study. We used a Bayesian model comparison method (BeviMed) to test for genotype-phenotype associations. Case-control labels were defined by diagnostic groupings and KCO and age strata. Competing models were fitted to identify associations between labels and rare variants under the dominant and recessive mode of inheritance and different variant consequence types. Results: We discovered a strong association between the protein-truncating variants (PTV) in KDR, which encodes VEGFR2, and PAH with low KCO (posterior probability (PP)=0.99) and older age at diagnosis (PP=0.91). Lung CT scans of patients harbouring PTV in KDR revealed a range of mild parenchymal abnormalities. One KDR subject had a family history of PAH. KCO stratification also highlighted an association between IDH3G and moderately reduced KCO in patients with PAH (PP=0.92). The US PAH Biobank was used to validate these findings and identified 4 additional PAH cases with PTVs in KDR and 3 in IDH3G. Conclusions: The smart study design allowed the discovery of new PAH risk, which further implicate central roles for the endothelium and alterations in mitochondrial respiration in PAH

Background Pulmonary arterial hypertension (PAH) is a fatal disease that results from cardio-pulmonary dysfunction with the pathology largely unknown. Insulin-like growth factor binding protein 2 (IGFBP2) is an important member of the insulin-like growth factor family, with evidence suggesting elevation in PAH patients. We investigated the diagnostic and prognostic value of serum IGFBP2 in PAH to determine if it could discriminate PAH from healthy controls and if it was associated with disease severity and survival. Methods Serum IGFBP2 levels, as well as IGF1/2 levels, were measured in two independent PAH cohorts, the Johns Hopkins Pulmonary Hypertension program (JHPH, N = 127), NHLBI PAHBiobank (PAHB, N = 203), and a healthy control cohort (N = 128). The protein levels in lung tissues were determined by western blot. The IGFBP2 mRNA expression levels in pulmonary artery smooth muscle cells (PASMC) and endothelial cells (PAEC) were assessed by RNA-seq, secreted protein levels by ELISA. Association of biomarkers with clinical variables was evaluated using adjusted linear or logistic regression and Kaplan-Meier analysis. Results In both PAH cohorts, serum IGFBP2 levels were significantly elevated (p p Conclusions IGFBP2 protein expression was increased in the PAH lung, and secreted by PASMC. Elevated circulating IGFBP2 was associated with PAH severity and mortality and is a potentially valuable prognostic marker in PAH.

Glucocerebrosidase (GCase, deficient in Gaucher disease) enzymatic activity measured in dried blood spots of Parkinson's Disease (PD) cases is within healthy range but reduced compared to controls. It is not known whether activities of additional lysosomal enzymes are reduced in dried blood spots in PD. To test whether reduction in lysosomal enzymatic activity in PD is specific to GCase, we measured GCase, acid sphingomyelinase (deficient in Niemann–Pick disease types A and B), alpha galactosidase A (deficient in Fabry), acid alpha-glucosidase (deficient in Pompe) and galactosylceramidase (deficient in Krabbe) enzymatic activities in dried blood spots of PD patients (n = 648) and controls (n = 317) recruited from Columbia University. Full sequencing of glucocerebrosidase (GBA) and the LRRK2 G2019S mutation was performed. Enzymatic activities were compared between PD cases and controls using t-test and regression models adjusted for age, gender, and GBA and LRRK2 G2019S mutation status. Alpha galactosidase A activity was lower in PD cases compared to controls both when only non-carriers were included (excluding all GBA and LRRK2 G2019S carriers and PD cases with age-at-onset below 40) [2.85 μmol/l/h versus 3.12 μmol/l/h, p = 0.018; after controlling for batch effect, p = 0.006 (468 PD cases and 296 controls)], and when including the entire cohort (2.89 μmol/l/h versus 3.10 μmol/l/h, p = 0.040; after controlling for batch effect, p = 0.011). Because the alpha galactosidase A gene is X-linked, we stratified the analyses by sex. Among women who were non-carriers of GBA and LRRK2 G2019S mutations (PD, n = 155; control, n = 194), alpha galactosidase A activity was lower in PD compared to controls (2.77 μmol/l/h versus 3.10 μmol/l/h, p = 0.044; after controlling for a batch effect, p = 0.001). The enzymatic activity of acid sphingomyelinase, acid alpha-glucosidase and galactosylceramidase was not significantly different between PD and controls. In non-carriers, most lysosomal enzyme activities were correlated, with the strongest association in GCase, acid alpha-glucosidase, and alpha galactosidase A (Pearson correlation coefficient between 0.382 and 0.532). In a regression model with all five enzymes among non-carriers (adjusted for sex and age), higher alpha galactosidase A activity was associated with lower odds of PD status (OR = 0.54; 95% CI:0.31–0.95; p = 0.032). When LRRK2 G2019S PD carriers (n = 37) were compared to non-carriers with PD, carriers had higher GCase, acid sphingomyelinase and alpha galactosidase A activity. We conclude that alpha galactosidase A may have a potential independent role in PD, in addition to GCase.

This study explores the racial and ethnic differences in presentation, severity, and treatment of patients with pulmonary arterial hypertension (PAH) in a large multicenter registry. African American and Hispanic patients are more likely to present with associated PAH compared to non-Hispanic whites. Hispanic patients with PAH were less likely to be treated with PAH-specific medications compared to non-Hispanic whites.

Objective To assess whether circulating interleukin-6 (IL-6) is associated with measures of disease severity and clinical worsening in pediatric pulmonary arterial hypertension (PAH). Study design IL-6 was measured by enzyme-linked immunosorbent assay in serum samples from a cross-sectional cohort from the National Heart, Lung, and Blood Institute Pulmonary Arterial Hypertension Biobank (n = 175) and a longitudinal cohort from Children's Hospital Colorado (CHC) (n = 61). Associations between IL-6, disease severity, and outcomes were studied with regression and Kaplan–Meier analysis. Results In analyses adjusted for age and sex, each log-unit greater IL-6 was significantly associated in the Pulmonary Arterial Hypertension Biobank cohort with greater pulmonary vascular resistance indices, lower odds of having idiopathic PAH or treatment with prostacyclin, and greater odds of having PAH associated with a repaired congenital shunt. In the CHC cohort, each log-unit greater IL-6 was significantly associated with greater mean pulmonary arterial pressure over time. Kaplan–Meier analysis in the CHC cohort revealed that IL-6 was significantly associated with clinical worsening (a composite score of mortality, transplant, or palliative surgery) (P = .037). Conclusions IL-6 was significantly associated with worse hemodynamics at baseline and over time and may be associated with clinical worsening. IL-6 may provide a less-invasive method for disease monitoring and prognosis in pediatric PAH as well as a potential therapeutic target.

Endostatin (ES) is an angiostatic peptide encoded by Col18a1. Our group has shown that a single nucleotide polymorphism (SNP) resulting in a missense mutation in Col18a1 is associated with altered disease severity and survival in PAH. We hypothesized that associations would exist between circulating serum ES levels and 1) clinical metrics of PAH severity, including survival and 2) SNPs in Col18a1. Serum samples and clinical data were obtained from 2,017 adult subjects in the PAH Biobank. Serum ES was measured with an electrochemiluminescent immunosorbent assay. Statistical associations between ES and clinical variables were examined with regression models. Genotyping was performed for protein quantitative trait loci (pQTL) analysis. Each log-unit increase in ES was associated with higher right atrial pressure (1.8 mmHg, 95% CI 1.3-2.3), higher mean pulmonary arterial pressure (2.0 mmHg, 95% CI 0.7 to 3.2), higher pulmonary vascular resistance (1.0 Wood unit, 95% CI 0.4 to 1.5), and lower 6 minute walk distance (-53.5m, 95 % CI -70.7 to -36.2). Mortality doubled for each log-unit increase in ES (2.3, 95% CI 1.6 to 3.4). In pQTL analysis, 4 SNPs in Col18a1 were associated with differences in circulating ES levels (Figure). Increased ES levels are associated with disease severity and survival in PAH, and several SNPs in Col18a1 are associated with differences in circulating ES levels. ES is a genetically-influenced determinant of disease severity in PAH.

The pro-inflammatory cytokine interleukin (IL)-6 has been associated with outcomes in small pulmonary arterial hypertension (PAH) cohorts composed largely of patients with severe idiopathic PAH (IPAH). It is unclear whether IL-6 is a marker of critical illness or a mechanistic biomarker of pulmonary vascular remodelling. We hypothesised that IL-6 is produced by pulmonary vascular cells and sought to explore IL-6 associations with phenotypes and outcomes across diverse subtypes in a large PAH cohort.IL-6 protein and gene expression levels were measured in cultured pulmonary artery smooth muscle cells (PASMCs) and endothelial cells (PAECs) from PAH patients and healthy controls. Serum IL-6 was measured in 2017 well-characterised PAH subjects representing each PAH subgroup. Relationships between IL-6 levels, clinical variables, and mortality were analysed using regression models.Significantly higher IL-6 protein and gene expression levels were produced by PASMCs than by PAECs in PAH (pIL-6 is released from PASMCs, and circulating IL-6 is associated with specific clinical phenotypes and outcomes in various PAH subgroups, including subjects with less severe disease. IL-6 is a mechanistic biomarker, and thus a potential therapeutic target, in certain PAH subgroups.

Background: Pulmonary arterial hypertension (PAH) is a rare disease characterized by pulmonary arteriole remodeling, elevated arterial pressure and resistance, and subsequent heart failure. Compared with adult-onset disease, pediatric-onset PAH is more heterogeneous and often associated with worse prognosis. Although BMPR2 mutations underlie ≈70% of adult familial PAH (FPAH) cases, the genetic basis of PAH in children is less understood. Methods: We performed genetic analysis of 155 pediatric- and 257 adult-onset PAH patients, including both FPAH and sporadic, idiopathic PAH (IPAH). After screening for 2 common PAH risk genes, mutation-negative FPAH and all IPAH cases were evaluated by exome sequencing. RESULTS: We observed similar frequencies of rare, deleterious BMPR2 mutations in pediatric- and adult-onset patients: ≈55% in FPAH and 10% in IPAH patients in both age groups. However, there was significant enrichment of TBX4 mutations in pediatric- compared with adult-onset patients (IPAH: 10/130 pediatric versus 0/178 adult-onset), and TBX4 carriers had younger mean age-of-onset compared with BMPR2 carriers. Mutations in other known PAH risk genes were infrequent in both age groups. Notably, among pediatric IPAH patients without mutations in known risk genes, exome sequencing revealed a 2-fold enrichment of de novo likely gene-damaging and predicted deleterious missense variants. Conclusions: Mutations in known PAH risk genes accounted for ≈70% to 80% of FPAH in both age groups, 21% of pediatric-onset IPAH, and 11% of adult-onset IPAH. Rare, predicted deleterious variants in TBX4 are enriched in pediatric patients and de novo variants in novel genes may explain ≈19% of pediatric-onset IPAH cases.

Background Multiple system atrophy (MSA) is marked by abnormal inclusions of α-synuclein in oligodendrogliocytes, and its etiology remains unknown. Variants in the glucocerebrosidase (GBA) gene have been associated with the other synucleinopathies, dementia with Lewy bodies, and Parkinson's disease. It is unclear whether glucocerebrosidase variants are associated with MSA. The objective of this study was to analyze the frequency of GBA variants among patients who had autopsy-proven MSA at a brain bank in New York City. Methods GBA was fully sequenced in brain tissues from 17 patients with autopsy-proven MSA for whom there was extractable DNA at the Columbia University New York Brain Bank from 2002 to 2016. To test whether brains from patients with MSA were enriched for GBA variants, the frequency of GBA variants in the MSA brains was compared with that of variants in all brains from patients with pure Alzheimer's disease (AD) at Columbia University for which GBA genotype was available (n = 82). Results Of 17 MSA brains, 4 carried GBA variants (23.5%), including 1 that was homozygous for N370S and 1 each that carried heterozygous N370S, T369M, and R496H variants. Among the comparator brains with pure AD, 3 of 82 (3.7%) carried GBA variants (P = 0.0127; Fisher exact test), including 1 each with an N370S homozygous variant, an R496H heterozygous variant, and a T369M heterozygous variant. Conclusion A higher frequency of GBA variants was observed among brains from patients who had pathologically diagnosed MSA compared with the frequency of variants in brains from patients who had AD. The results indicate a need for further investigation into the role of glucocerebrosidase and lysosomal dysfunction in the etiology of MSA.

Background Few studies have systematically investigated the association between PARKIN genotype and psychiatric co-morbidities of Parkison's disease (PD). PARKIN-associated PD is characterized by severe nigral dopaminergic neuronal loss, a finding that may have implications for behaviors rooted in dopaminergic circuits such as obsessive-compulsive symptoms (OCS). Methods The Schedule of Compulsions and Obsessions Patient Inventory (SCOPI) was administered to 104 patients with early-onset PD and 257 asymptomatic first-degree relatives. Carriers of one and two PARKIN mutations were compared with noncarriers. Results Among patients, carriers scored lower than noncarriers in adjusted models (one-mutation: 13.9 point difference, P = 0.03; two-mutation: 24.1, P = 0.001), where lower scores indicate less OCS. Among asymptomatic relatives, a trend toward the opposite was seen: mutation carriers scored higher than noncarriers (one mutation, P = 0.05; two mutations, P = 0.13). Conclusions First, a significant association was found between PARKIN mutation status and obsessive-compulsive symptom level in both PD and asymptomatic patients, suggesting that OCS might represent an early non-motor dopamine-dependent feature. Second, irrespective of disease status, heterozygotes were significantly different from noncarriers, suggesting that PARKIN heterozygosity may contribute to phenotype. © 2014 International Parkinson and Movement Disorder Society

Rare variants in the T-box transcription factor 4 gene (TBX4) have recently been recognised as an emerging cause of paediatric pulmonary hypertension (PH). Their pathophysiology and contribution to persistent pulmonary hypertension in neonates (PPHN) are unknown. We sought to define the spectrum of clinical manifestations and histopathology associated with TBX4 variants in neonates and children with PH.We assessed clinical data and lung tissue in 19 children with PH, including PPHN, carrying TBX4 rare variants identified by next-generation sequencing and copy number variation arrays.Variants included six 17q23 deletions encompassing the entire TBX4 locus and neighbouring genes, and 12 likely damaging mutations. 10 infants presented with neonatal hypoxic respiratory failure and PPHN, and were subsequently discharged home. PH was diagnosed later in infancy or childhood. Three children died and two required lung transplantation. Associated anomalies included patent ductus arteriosus, septal defects, foot anomalies and developmental disability, the latter with a higher prevalence in deletion carriers. Histology in seven infants showed abnormal distal lung development and pulmonary hypertensive remodelling.TBX4 mutations and 17q23 deletions underlie a new form of developmental lung disease manifesting with severe, often biphasic PH at birth and/or later in infancy and childhood, often associated with skeletal anomalies, cardiac defects, neurodevelopmental disability and other anomalies.

The phenotype of Parkinson's disease (PD) in patients with and without leucine-rich repeat kinase 2 (LRRK2) G2019S mutations reportedly is similar; however, large, uniformly evaluated series are lacking. The objective of this study was to characterize the clinical phenotype of Ashkenazi Jewish (AJ) PD carriers of the LRRK2 G2019S mutation. We studied 553 AJ PD patients, including 65 patients who were previously reported, from three sites (two in New York and one in Tel-Aviv). Glucocerebrosidase (GBA) mutation carriers were excluded. Evaluations included the Montreal Cognitive Assessment (MoCA), the Unified Parkinson's Disease Rating Scale (UPDRS), the Geriatric Depression Scale (GDS) and the Non-Motor Symptoms (NMS) questionnaire. Regression models were constructed to test the association between clinical and demographic features and LRRK2 status (outcome) in 488 newly recruited participants. LRRK2 G2019S carriers (n = 97) and non-carriers (n = 391) were similar in age and age at onset of PD. Carriers had longer disease duration (8.6 years vs. 6.1 years; P 5 years (P = 0.042). Performance on the UPDRS, MoCA, GDS, and NMS did not differ by mutation status. PD in AJ LRRK2 G2019S mutation carriers is similar to idiopathic PD but is characterized by more frequent lower extremity involvement at onset and PIGD without the associated cognitive impairment.

Objective In a cohort of patients with young-onset Parkinson's disease (PD), the authors assessed (1) the prevalence of genetic mutations in those who enrolled in deep brain stimulation (DBS) programs compared with those who did not enroll DBS programs and (2) specific genetic and clinical predictors of DBS enrollment. Methods Subjects were participants from 3 sites (Columbia University, Rush University, and the University of Pennsylvania) in the Consortium on Risk for Early Onset Parkinson's Disease (CORE-PD) who had an age at onset < 51 years. The analyses presented here focus on glucocerebrosidase (GBA), leucine-rich repeat kinase 2 (LRRK2), and parkin (PRKN) mutation carriers. Mutation carrier status, demographic data, and disease characteristics in individuals who did and did not enroll in DBS were analyzed. The association between mutation status and DBS placement was assessed in logistic regression models. Results Patients who had PD with either GBA, LRRK2, or PRKN mutations were more common in the DBS group (n = 99) compared with the non-DBS group (n = 684; 26.5% vs. 16.8%, respectively; P = 0.02). In a multivariate logistic regression model, GBA mutation status (odds ratio, 2.1; 95% confidence interval, 1.0–4.3; P = 0.05) was associated with DBS surgery enrollment. However, when dyskinesia was included in the multivariate logistic regression model, dyskinesia had a strong association with DBS placement (odds ratio, 3.8; 95% confidence interval, 1.9–7.3; P < 0.0001), whereas the association between GBA mutation status and DBS placement did not persist (P = 0.25). Conclusions DBS populations are enriched with genetic mutation carriers. The effect of genetic mutation carriers on DBS outcomes warrants further exploration.

Pulmonary hypertension is associated with reduced nitric oxide bioavailability and early mortality in sickle cell disease (SCD). We previously demonstrated that placenta growth factor (PlGF), an angiogenic factor produced by erythroid cells, induces hypoxia-independent expression of the pulmonary vasoconstrictor endothelin-1 in pulmonary endothelial cells. Using a lentivirus vector, we simulated erythroid expression of PlGF in normal mice up to the levels seen in sickle mice. Consequently, endothelin-1 production increased, right ventricle pressures increased, and right ventricle hypertrophy and pulmonary changes occurred in the mice within 8 weeks. These findings were corroborated in 123 patients with SCD, in whom plasma PlGF levels were significantly associated with anemia, endothelin-1, and tricuspid regurgitant velocity; the latter is reflective of peak pulmonary artery pressure. These results illuminate a novel mechanistic pathway linking hemolysis and erythroid hyperplasia to increased PlGF, endothelin-1, and pulmonary hypertension in SCD, and suggest that strategies that block PlGF signaling may be therapeutically beneficial. This trial was registered at http://clinicaltrials.gov as #NCT00011648.

Prior US registries PAH have demonstrated changing demographics with, increasing female preponderance but have not included genomic data or hormonal information. USPHSR is a multicenter observational study to characterize demographics(with an emphasis on hormonal history), genomics, and clinical

Glucocerebrosidase (GBA) mutations have been associated with Parkinson's disease in numerous studies. However, it is unknown whether the increased risk of Parkinson's disease in GBA carriers is due to a loss of glucocerebrosidase enzymatic activity. We measured glucocerebrosidase enzymatic activity in dried blood spots in patients with Parkinson's disease (n = 517) and controls (n = 252) with and without GBA mutations. Participants were recruited from Columbia University, New York, and fully sequenced for GBA mutations and genotyped for the LRRK2 G2019S mutation, the most common autosomal dominant mutation in the Ashkenazi Jewish population. Glucocerebrosidase enzymatic activity in dried blood spots was measured by a mass spectrometry-based assay and compared among participants categorized by GBA mutation status and Parkinson's disease diagnosis. Parkinson's disease patients were more likely than controls to carry the LRRK2 G2019S mutation (n = 39, 7.5% versus n = 2, 0.8%, P < 0.001) and GBA mutations or variants (seven homozygotes and compound heterozygotes and 81 heterozygotes, 17.0% versus 17 heterozygotes, 6.7%, P < 0.001). GBA homozygotes/compound heterozygotes had lower enzymatic activity than GBA heterozygotes (0.85 µmol/l/h versus 7.88 µmol/l/h, P < 0.001), and GBA heterozygotes had lower enzymatic activity than GBA and LRRK2 non-carriers (7.88 µmol/l/h versus 11.93 µmol/l/h, P < 0.001). Glucocerebrosidase activity was reduced in heterozygotes compared to non-carriers when each mutation was compared independently (N370S, P < 0.001; L444P, P < 0.001; 84GG, P = 0.003; R496H, P = 0.018) and also reduced in GBA variants associated with Parkinson's risk but not with Gaucher disease (E326K, P = 0.009; T369M, P < 0.001). When all patients with Parkinson's disease were considered, they had lower mean glucocerebrosidase enzymatic activity than controls (11.14 µmol/l/h versus 11.85 µmol/l/h, P = 0.011). Difference compared to controls persisted in patients with idiopathic Parkinson's disease (after exclusion of all GBA and LRRK2 carriers; 11.53 µmol/l/h, versus 12.11 µmol/l/h, P = 0.036) and after adjustment for age and gender (P = 0.012). Interestingly, LRRK2 G2019S carriers (n = 36), most of whom had Parkinson's disease, had higher enzymatic activity than non-carriers (13.69 µmol/l/h versus 11.93 µmol/l/h, P = 0.002). In patients with idiopathic Parkinson's, higher glucocerebrosidase enzymatic activity was associated with longer disease duration (P = 0.002) in adjusted models, suggesting a milder disease course. We conclude that lower glucocerebrosidase enzymatic activity is strongly associated with GBA mutations, and modestly with idiopathic Parkinson's disease. The association of lower glucocerebrosidase activity in both GBA mutation carriers and Parkinson's patients without GBA mutations suggests that loss of glucocerebrosidase function contributes to the pathogenesis of Parkinson's disease. High glucocerebrosidase enzymatic activity in LRRK2 G2019S carriers may reflect a distinct pathogenic mechanism. Taken together, these data suggest that glucocerebrosidase enzymatic activity could be a modifiable therapeutic target.

A total of 956 individuals with Parkinson's disease (PD) from 430 multiplex PD pedigrees were screened for 12 previously reported, pathogenic LRRK2 mutations: R793M, L1114L, I1371V, R1441C, R1441G, R1441H, Y1699C, M1869T, I2012T, I2020T, G2385R, and IVS31 +3G > A. Previous screening identified the LRRK2 G2019S mutation in 5% of our families. Only 1 of the 12 newly screened mutations, R1441C, was detected in a single family in our patient cohort. These results indicate that, although the G2019S mutation remains the most common mutation identified in familial PD patients, other mutations in LRRK2 are infrequent.

Background: Spheroid body myopathy (SBM) is a rare, autosomal dominant, neuromuscular disorder, which has only been previously reported in a single large kindred. Identification of the mutated gene in this disorder may provide insight regarding abnormal neuromuscular function. Methods: The authors completed a detailed clinical evaluation on an extensive kindred diagnosed with SBM. Genome-wide linkage analysis was performed to localize the disease gene to a specific chromosomal region. Further marker genotyping and screening of a positional, functional candidate gene were completed to detect the disease-causing mutation. Pathologic analysis of muscle biopsy was performed on three individuals. Biochemical studies were performed on one muscle biopsy specimen from an affected individual. Results: Linkage to chromosome 5q23-5q31 was detected with a lod score of 2.9. Genotyping of additional markers in a larger sample of family members produced a maximum lod score of 6.1 and narrowed the critical interval to 12.2 cM. Screening of the candidate gene titin immunoglobulin domain protein ( TTID , also known as MYOT ) detected a cytosine-to-thymine mutation in exon 2 of all clinically affected family members. Similar pathologic changes were present in all muscle biopsy specimens. Immunohistologic and biochemical analysis revealed that the TTID protein, also known as myotilin, is a component of the insoluble protein aggregate. Conclusions: A novel mutation in the TTID gene results in the clinical and pathologic phenotype termed “spheroid body myopathy.” Mutations in this gene also cause limb-girdle muscular dystrophy 1A and are associated with myofibrillar myopathy.

Importance Information on age-specific risk for Parkinson disease (PD) in patients with Gaucher disease (GD) and glucocerebrosidase ( GBA ) heterozygotes is important for understanding the pathophysiology of the genetic association and for counseling these populations. Objective To estimate the age-specific risk for PD in Ashkenazi Jewish patients with type 1 GD and in GBA heterozygotes. Design, Setting, and Participants The study included patients with GD from 2 tertiary centers, Shaare Zedek Medical Center, Jerusalem, Israel (n = 332) and Mount Sinai School of Medicine, New York, New York (n = 95). GBA noncarrier non-PD spouse control participants were recruited at the Center for Parkinson’s Disease at Columbia University, New York (n = 77). All participants were Ashekanzi Jewish and most patients (98.1%) with GD carried at least 1 N370S mutation. Main Outcomes and Measures The main outcome measure was a diagnosis of PD. Diagnosis was established in patients with GD on examination. We used a validated family history interview that identifies PD with a sensitivity of 95.5% and specificity of 96.2% to identify PD in family members. Kaplan-Meier survival curves were used to estimate age-specific PD risk among patients with GD (n = 427), among their parents who are obligate GBA mutation carriers (heterozygotes, n = 694), and among noncarriers (parents of non-PD, non-GD control participants, n = 154). The age-specific risk was compared among groups using the log-rank test. Results Among those who developed PD, patients with GD had a younger age at onset than GBA heterozygotes (mean, 54.2 vs 65.2 years, respectively; P = .003). Estimated age-specific risk for PD at 60 and 80 years of age was 4.7% and 9.1% among patients with GD, 1.5% and 7.7% among heterozygotes, and 0.7% and 2.1% among noncarriers, respectively. The risk for PD was higher in patients with GD than noncarriers ( P = .008, log-rank test) and in heterozygotes than noncarriers ( P = .03, log-rank test), but it did not reach statistical significance between patients with GD and GBA heterozygotes ( P = .07, log-rank test). Conclusions and Relevance Patients with GD and GBA heterozygotes have an increased age-specific risk for PD compared with control individuals, with a similar magnitude of PD risk by 80 years of age; however, the number of mutant alleles may play an important role in age at PD onset.

BACKGROUND: Most patients with familial primary pulmonary hypertension have defects in the gene for bone morphogenetic protein receptor II (BMPR2), a member of the transforming growth factor beta (TGF-beta) superfamily of receptors. Because patients with hereditary hemorrhagic telangiectasia may have lung disease that is indistinguishable from primary pulmonary hypertension, we investigated the genetic basis of lung disease in these patients. METHODS: We evaluated members of five kindreds plus one individual patient with hereditary hemorrhagic telangiectasia and identified 10 cases of pulmonary hypertension. In the two largest families, we used microsatellite markers to test for linkage to genes encoding TGF-beta-receptor proteins, including endoglin and activin-receptor-like kinase 1 (ALK1), and BMPR2. In subjects with hereditary hemorrhagic telangiectasia and pulmonary hypertension, we also scanned ALK1 and BMPR2 for mutations. RESULTS: We identified suggestive linkage of pulmonary hypertension with hereditary hemorrhagic telangiectasia on chromosome 12q13, a region that includes ALK1. We identified amino acid changes in activin-receptor-like kinase 1 that were inherited in subjects who had a disorder with clinical and histologic features indistinguishable from those of primary pulmonary hypertension. Immunohistochemical analysis in four subjects and one control showed pulmonary vascular endothelial expression of activin-receptor-like kinase 1 in normal and diseased pulmonary arteries. CONCLUSIONS: Pulmonary hypertension in association with hereditary hemorrhagic telangiectasia can involve mutations in ALK1. These mutations are associated with diverse effects, including the vascular dilatation characteristic of hereditary hemorrhagic telangiectasia and the occlusion of small pulmonary arteries that is typical of primary pulmonary hypertension.

Primary pulmonary hypertension (PPH) is a potentially lethal disorder, because the elevation of the pulmonary arterial pressure may result in right-heart failure. Histologically, the disorder is characterized by proliferation of pulmonary-artery smooth muscle and endothelial cells, by intimal hyperplasia, and by in situ thrombus formation. Heterozygous mutations within the bone morphogenetic protein type II receptor (BMPR-II) gene (BMPR2), of the transforming growth factor beta (TGF-beta) cell-signaling superfamily, have been identified in familial and sporadic cases of PPH. We report the molecular spectrum of BMPR2 mutations in 47 additional families with PPH and in three patients with sporadic PPH. Among the cohort of patients, we have identified 22 novel mutations, including 4 partial deletions, distributed throughout the BMPR2 gene. The majority (58%) of mutations are predicted to lead to a premature termination codon. We have also investigated the functional impact and genotype-phenotype relationships, to elucidate the mechanisms contributing to pathogenesis of this important vascular disease. In vitro expression analysis demonstrated loss of BMPR-II function for a number of the identified mutations. These data support the suggestion that haploinsufficiency represents the common molecular mechanism in PPH. Marked variability of the age at onset of disease was observed both within and between families. Taken together, these studies illustrate the considerable heterogeneity of BMPR2 mutations that cause PPH, and they strongly suggest that additional factors, genetic and/or environmental, may be required for the development of the clinical phenotype.

Importance Data on the long-term cognitive outcomes of patients with PARKIN -associated Parkinson disease (PD) are unknown but may be useful when counseling these patients. Objective Among patients with early-onset PD of long duration, we assessed cognitive and motor performances, comparing homozygotes and compound heterozygotes who carry 2 PARKIN mutations with noncarriers. Design, Setting, and Participants Cross-sectional study of 44 participants at 17 different movement disorder centers who were in the Consortium on Risk for Early-Onset PD study with a duration of PD greater than the median duration (>14 years): 4 homozygotes and 17 compound heterozygotes (hereafter referred to as carriers) and 23 noncarriers. Main Outcomes and Measures Unified Parkinson Disease Rating Scale Part III (UPDRS-III) and Clinical Dementia Rating scores and neuropsychological performance. Linear regression models were applied to assess the association between PARKIN mutation status and cognitive domain scores and UPDRS-III scores. Models were adjusted for age, education, disease duration, language, and levodopa equivalent daily dose. Results Carriers had an earlier age at onset of PD ( P P = .004) at time of examination than noncarriers. They performed better than noncarriers on the Mini-Mental State Examination ( P = .010) and were more likely to receive lower scores on the Clinical Dementia Rating ( P = .003). In multivariate analyses, carriers performed better than noncarriers on the UPDRS-III ( P = .02) and on tests of attention ( P = .03), memory ( P = .03), and visuospatial ( P = .02) cognitive domains. Conclusions and Relevance In cross-sectional analyses, carriers demonstrated better cognitive and motor performance than did noncarriers with long disease duration, suggesting slower disease progression. A longitudinal follow-up study is required to confirm these findings.

Objective: To characterize sequence variation within the glucocerebrosidase ( GBA ) gene in a select subset of our sample of patients with familial Parkinson disease (PD) and then to test in our full sample whether these sequence variants increased the risk for PD and were associated with an earlier onset of disease. Methods: We performed a comprehensive study of all GBA exons in one patient with PD from each of 96 PD families, selected based on the family-specific lod scores at the GBA locus. Identified GBA variants were subsequently screened in all 1325 PD cases from 566 multiplex PD families and in 359 controls. Results: Nine different GBA variants, five previously reported, were identified in 21 of the 96 PD cases sequenced. Screening for these variants in the full sample identified 161 variant carriers (12.2%) in 99 different PD families. An unbiased estimate of the frequency of the five previously reported GBA variants in the familial PD sample was 12.6% and in the control sample was 5.3% (odds ratio 2.6; 95% confidence interval 1.5–4.4). Presence of a GBA variant was associated with an earlier age at onset ( p = 0.0001). On average, those patients carrying a GBA variant had onset with PD 6.04 years earlier than those without a GBA variant. Conclusions: This study suggests that GBA is a susceptibility gene for familial Parkinson disease (PD) and patients with GBA variants have an earlier age at onset than patients with PD without GBA variants.

Background Neurofibromatosis type 1 (NF1) is a common disorder of dysregulated tissue growth secondary to mutations in the tumor suppressor gene NF1. Pulmonary arterial hypertension (PAH) in patients with NF1 is hypothesized to be secondary to an underlying vasculopathy. Methods We describe the entity we term NF1-associated PAH (NF1-PAH) in four new patients and update the data on four previously published reports of patients with PAH and NF1. We performed genetic testing of the bone morphogenic protein receptor 2 (BMPR2) gene, which is mutated in 70% of patients with familial PAH and approximately 25% of patients with idiopathic PAH. We report, for the first time, pathologic findings in the autopsy-obtained lung of one patient with NF1-PAH. Results Patients with NF1-PAH have a generally poor long-term prognosis. In four patients, we observed the mosaic pattern of lung attenuation on a CT scan of the chest, a radiographic finding that can be consistent with an underlying vasculopathy. No mutations or rearrangements in the BMPR2 gene were found. We observed complex plexiform lesions in the one available autopsy specimen. Similar lesions are a hallmark of plexogenic pulmonary arteriopathy and are associated with several severe types of PAH. (Plexiform lesions should not be confused with plexiform neurofibromas, which are distinctive tumors seen in NF1.) Conclusions Our findings suggest that NF1 should be considered as being "associated with PAH" as outlined in the Revised Clinical Classification of Pulmonary Hypertension. Understanding the mechanism of PAH in NF1 may inform the pathogenesis of PAH, NF1-PAH itself, and other NF1-associated vasculopathies. The pulmonary vasculature should now be included among the arterial beds affected by NF1 vasculopathy.

BACKGROUND—Primary pulmonary hypertension (PPH), resulting from occlusion of small pulmonary arteries, is a devastating condition. Mutations of the bone morphogenetic protein receptor type II gene (BMPR2), a component of the transforming growth factor beta (TGF-β) family which plays a key role in cell growth, have recently been identified as causing familial PPH. We have searched for BMPR2 gene mutations in sporadic PPH patients to determine whether the same genetic defect underlies the more common form of the disorder. METHODS—We investigated 50 unrelated patients, with a clinical diagnosis of PPH and no identifiable family history of pulmonary hypertension, by direct sequencing of the entire coding region and intron/exon boundaries of the BMPR2 gene. DNA from available parent pairs (n=5) was used to assess the occurrence of spontaneous (de novo) mutations contributing to sporadic PPH. RESULTS—We found a total of 11 different heterozygous germline mutations of the BMPR2 gene in 13 of the 50 PPH patients studied, including missense (n=3), nonsense (n=3), and frameshift (n=5) mutations each predicted to alter the cell signalling response to specific ligands. Parental analysis showed three occurrences of paternal transmission and two of de novo mutation of the BMPR2 gene in sporadic PPH. CONCLUSION—The sporadic form of PPH is associated with germline mutations of the gene encoding the receptor protein BMPR-II in at least 26% of cases. A molecular classification of PPH, based upon the presence or absence of BMPR2 mutations, has important implications for patient management and screening of relatives. Keywords: primary pulmonary hypertension; BMPR2; BMPR-II; TGF-β

Idiopathic pulmonary arterial hypertension (IPAH; formerly known as primary pulmonary hypertension, PPH) is a rare disorder characterised by pulmonary vascular proliferation and remodelling resulting in loss of patency of the pulmonary arteries. This leads to sustained elevation of pulmonary artery pressures with subsequent progressive right heart failure and often death.1–3 While the majority of cases (>90%) have no known family history of the disease, ∼6% of the cases are known to be familial and are inherited in an autosomal dominant manner with markedly reduced penetrance.4 In previous studies, linkage analysis identified a familial IPAH locus on chromosome 2q33.5,6 Subsequent heterozygous germline mutations in the bone morphogenetic protein receptor, type II (BMPR II) gene ( BMPR2 ) were identified in at least 50% of familial cases.7–9 BMPR-II is a member of the transforming growth factor-β (TGF-β) receptor superfamily signalling pathway, which is critical in both cell differentiation and cell growth mediated through transcriptional regulation.10,11 Interestingly, germline mutations were also identified in 26–40% of sporadic cases.12,13 This study was performed to establish the frequency of BMPR2 mutations in a different population of patients with sporadic IPAH. ### Patients Between March 2002 and January 2004, 99 consecutive non-related patients >20 years of age with IPAH and negative family history were evaluated. In all cases, diagnosis of IPAH was made by experienced and specialised cardiologists or pulmonologists according to WHO criteria.1,14 Other causes of pulmonary hypertension such as illicit drug abuse or anorectic drug use were excluded by careful medical history evaluation. Underlying heart and lung diseases (recurrent pulmonary embolism, connective tissue disease, obstructive or restrictive lung disease) and HIV infection were excluded by a cascade of clinical examinations including laboratory tests, arterial blood gas analysis, chest x ray, pulmonary function tests, echocardiography, ventilation perfusion …

ObjectivesThe aim of our study was to identify genetic causes of primary pulmonary hypertension (PPH), to estimate the proportion of families with mutations in the BMPR2 (bone morphogenetic protein receptor type 2) gene, and to examine whether genetic heterogeneity might play a role.BackgroundThe BMPR2 mutations have been identified in a substantial portion of patients with familial or sporadic PPH. However, the genetic cause of PPH remains unclear in at least 45% of families.MethodsWe investigated 130 members of 10 families with at least 1 PPH patient, recruited without selection for familial disease. Manifest PPH was documented in 21 individuals. An increase in pulmonary artery systolic pressure (PASP) above 40 mm Hg during supine bicycle exercise was found in 46 healthy individuals. Their PASP increased from 21.0 ± 4.6 mm Hg at rest to 54.0 ± 9.8 mm Hg during exercise. In 51 relatives, PASP values were normal at rest and during exercise, and 12 members were classified as status unknown.ResultsTwo families showed a mutation in the BMPR2 gene. Three families with no BMBR2 mutation showed evidence for linkage to a more proximal location on chromosome 2q31 (odds ratio [OR] for linkage 1.1·106:1). This locus, designated PPH2, maps in-between the markers D2S335 and D2S2314. We obtained significant support for heterogeneity in PPH with an OR of 2.8·1011.ConclusionsWe conclude that PPH may be a genetically heterogeneous disorder with at least two—and possibly more—causative genes.