Asthma prescribing according to Arg16Gly beta-2 genotype: a randomised trial in adolescents.

INTRODUCTION: The A allele of rs1042713 (Arg16 amino acid) in the ß2-adrenoreceptor is associated with poor response to long-acting ß2-agonist (LABA) in young people with asthma. Our aim was to assess whether the prescribing of second-line controller with LABA or a leukotriene receptor antagonist according to Arg16Gly genotype would result in improvements in Pediatric Asthma-Related Quality of Life Questionnaire (PAQLQ). METHODS: We performed a pragmatic randomised controlled trial (RCT) via a primary care clinical research network covering England and Scotland. We enrolled participants aged 12-18 years with asthma taking inhaled corticosteroids. 241 participants (mean±sd age 14.7±1.91 years) were randomised (1:1) to receive personalised care (genotype directed prescribing) or standard guideline care. Following a 4-week run-in participants were followed for 12 months. The primary outcome measure was change in PAQLQ. Asthma control, asthma exacerbation frequency and healthcare utilisation were secondary outcomes. RESULTS: Genotype-directed prescribing resulted in an improvement in PAQLQ compared to standard care (0.16, 95% CI 0.00-0.31; p=0.049), although this improvement was below the pre-determined clinical threshold of 0.25. The AA genotype was associated with a larger improvement in PAQLQ with personalised versus standard care (0.42, 95% CI 0.02-0.81; p=0.041). CONCLUSION: This is the first RCT demonstrating that genotype-driven asthma prescribing is associated with a significant improvement in a clinical outcome compared to standard care. Adolescents with the AA homozygous genotype benefited most. The potential role of such ß2-adrenoceptor genotype directed therapy in younger and more severe childhood asthma warrants further exploration.

Genome-wide association study of asthma exacerbations despite inhaled corticosteroid use.

RATIONALE: Substantial variability in response to asthma treatment with inhaled corticosteroids (ICS) has been described among individuals and populations, suggesting the contribution of genetic factors. Nonetheless, only a few genes have been identified to date. We aimed to identify genetic variants associated with asthma exacerbations despite ICS use in European children and young adults and to validate the findings in non-Europeans. Moreover, we explored whether a gene-set enrichment analysis could suggest potential novel asthma therapies. METHODS: A genome-wide association study (GWAS) of asthma exacerbations was tested in 2681 children of European descent treated with ICS from eight studies. Suggestive association signals were followed up for replication in 538 European asthma patients. Further evaluation was performed in 1773 non-Europeans. Variants revealed by published GWAS were assessed for replication. Additionally, gene-set enrichment analysis focused on drugs was performed. RESULTS: 10 independent variants were associated with asthma exacerbations despite ICS treatment in the discovery phase (p≤5×10-6). Of those, one variant at the CACNA2D3-WNT5A locus was nominally replicated in Europeans (rs67026078; p=0.010), but this was not validated in non-European populations. Five other genes associated with ICS response in previous studies were replicated. Additionally, an enrichment of associations in genes regulated by trichostatin A treatment was found. CONCLUSIONS: The intergenic region of CACNA2D3 and WNT5A was revealed as a novel locus for asthma exacerbations despite ICS treatment in European populations. Genes associated were related to trichostatin A, suggesting that this drug could regulate the molecular mechanisms involved in treatment response.

Genome-wide association study of inhaled corticosteroid response in admixed children with asthma.

BACKGROUND: Inhaled corticosteroids (ICS) are the most widely prescribed and effective medication to control asthma symptoms and exacerbations. However, many children still have asthma exacerbations despite treatment, particularly in admixed populations, such as Puerto Ricans and African Americans. A few genome-wide association studies (GWAS) have been performed in European and Asian populations, and they have demonstrated the importance of the genetic component in ICS response. OBJECTIVE: We aimed to identify genetic variants associated with asthma exacerbations in admixed children treated with ICS and to validate previous GWAS findings. METHODS: A meta-analysis of two GWAS of asthma exacerbations was performed in 1347 admixed children treated with ICS (Hispanics/Latinos and African Americans), analysing 8.7 million genetic variants. Those with P ≤ 5 × 10-6 were followed up for replication in 1697 asthmatic patients from six European studies. Associations of ICS response described in published GWAS were followed up for replication in the admixed populations. RESULTS: A total of 15 independent variants were suggestively associated with asthma exacerbations in admixed populations (P ≤ 5 × 10-6 ). One of them, located in the intergenic region of APOBEC3B and APOBEC3C, showed evidence of replication in Europeans (rs5995653, P = 7.52 × 10-3 ) and was also associated with change in lung function after treatment with ICS (P = 4.91 × 10-3 ). Additionally, the reported association of the L3MBTL4-ARHGAP28 genomic region was confirmed in admixed populations, although a different variant was identified. CONCLUSIONS AND CLINICAL RELEVANCE: This study revealed the novel association of APOBEC3B and APOBEC3C with asthma exacerbations in children treated with ICS and replicated previously identified genomic regions. This contributes to the current knowledge about the multiple genetic markers determining responsiveness to ICS which could lead in the future the clinical identification of those asthma patients who are not able to respond to such treatment.

Genetic mannose binding lectin deficiency is associated with airway microbiota diversity and reduced exacerbation frequency in COPD.

BACKGROUND: In cystic fibrosis and bronchiectasis, genetic mannose binding lectin (MBL) deficiency is associated with increased exacerbations and earlier mortality; associations in COPD are less clear. Preclinical data suggest MBL interferes with phagocytosis of Haemophilus influenzae, a key COPD pathogen. We investigated whether MBL deficiency impacted on clinical outcomes or microbiota composition in COPD. METHODS: Patients with COPD (n=1796) underwent MBL genotyping; linkage to health records identified exacerbations, lung function decline and mortality. A nested subcohort of 141 patients, followed for up to 6 months, was studied to test if MBL deficiency was associated with altered sputum microbiota, through 16S rRNA PCR and sequencing, or airway inflammation during stable and exacerbated COPD. FINDINGS: Patients with MBL deficiency with COPD were significantly less likely to have severe exacerbations (incidence rate ratio (IRR) 0.66, 95% CI 0.48 to 0.90, p=0.009), or to have moderate or severe exacerbations (IRR 0.77, 95% CI 0.60 to 0.99, p=0.047). MBL deficiency did not affect rate of FEV1 decline or mortality. In the subcohort, patients with MBL deficiency had a more diverse lung microbiota (p=0.008), and were less likely to be colonised with Haemophilus spp. There were lower levels of airway inflammation in patients with MBL deficiency. INTERPRETATION: Patients with MBL deficient genotype with COPD have a lower risk of exacerbations and a more diverse lung microbiota. This is the first study to identify a genetic association with the lung microbiota in COPD.

A common missense variant of LILRB5 is associated with statin intolerance and myalgia.

Aims: A genetic variant in LILRB5 (leukocyte immunoglobulin-like receptor subfamily-B) (rs12975366: T > C: Asp247Gly) has been reported to be associated with lower creatine phosphokinase (CK) and lactate dehydrogenase (LDH) levels. Both biomarkers are released from injured muscle tissue, making this variant a potential candidate for susceptibility to muscle-related symptoms. We examined the association of this variant with statin intolerance ascertained from electronic medical records in the GoDARTS study. Methods and results: In the GoDARTS cohort, the LILRB5 Asp247 variant was associated with statin intolerance (SI) phenotypes; one defined as having raised CK and being non-adherent to therapy [odds ratio (OR) 1.81; 95% confidence interval (CI): 1.34-2.45] and the other as being intolerant to the lowest approved dose of a statin before being switched to two or more other statins (OR 1.36; 95% CI: 1.07-1.73). Those homozygous for Asp247 had increased odds of developing both definitions of intolerance. Importantly the second definition did not rely on CK elevations. These results were replicated in adjudicated cases of statin-induced myopathy in the PREDICTION-ADR consortium (OR1.48; 95% CI: 1.05-2.10) and for the development of myalgia in the JUPITER randomized clinical trial of rosuvastatin (OR1.35, 95% CI: 1.10-1.68). A meta-analysis across the studies showed a consistent association between Asp247Gly and outcomes associated with SI (OR1.34; 95% CI: 1.16-1.54). Conclusion: This study presents a novel immunogenetic factor associated with statin intolerance, an important risk factor for cardiovascular outcomes. The results suggest that true statin-induced myalgia and non-specific myalgia are distinct, with a potential role for the immune system in their development. We identify a genetic group that is more likely to be intolerant to their statins.

Childhood asthma exacerbations and the Arg16 ß2-receptor polymorphism: A meta-analysis stratified by treatment.

BACKGROUND: The Gly-to-Arg substitution at the 16 position (rs1042713) in the ß2-adrenoceptor gene (ADRB2) is associated with enhanced downregulation and uncoupling of ß2-receptors. OBJECTIVES: We sought to undertake a meta-analysis to test the hypothesis that there is an interaction between the A allele of rs1042713 (Arg16 amino acid) and long-acting ß-agonist (LABA) exposure for asthma exacerbations in children. METHODS: Children with diagnosed asthma were recruited in 5 populations (BREATHE, Genes-Environments and Admixture in Latino Americans II, PACMAN, the Paediatric Asthma Gene Environment Study, and the Pharmacogenetics of Adrenal Suppression with Inhaled Steroid Study). A history of recent exacerbation and asthma treatment was determined from questionnaire data. DNA was extracted, and the Gly16Arg genotype was determined. RESULTS: Data from 4226 children of white Northern European and Latino origin were analyzed, and the odds ratio for exacerbation increased by 1.52 (95% CI, 1.17-1.99; P = .0021) for each copy of the A allele among the 637 children treated with inhaled corticosteroids (ICSs) plus LABAs but not for treatment with ICSs alone (n = 1758) or ICSs plus leukotriene receptor antagonist (LTRAs; n = 354) or ICSs plus LABAs plus LTRAs (n = 569). CONCLUSIONS: The use of a LABA but not an LTRA as an "add-on controller" is associated with increased risk of asthma exacerbation in children carrying 1 or 2 A alleles at rs1042713. Prospective genotype-stratified clinical trials are now required to explore the potential role of rs1042713 genotyping for personalized asthma therapy in children.

Exome-wide analysis of rare coding variation identifies novel associations with COPD and airflow limitation in MOCS3, IFIT3 and SERPINA12.

BACKGROUND: Several regions of the genome have shown to be associated with COPD in genome-wide association studies of common variants. OBJECTIVE: To determine rare and potentially functional single nucleotide polymorphisms (SNPs) associated with the risk of COPD and severity of airflow limitation. METHODS: 3226 current or former smokers of European ancestry with lung function measures indicative of Global Initiative for Chronic Obstructive Lung Disease (GOLD) 2 COPD or worse were genotyped using an exome array. An analysis of risk of COPD was carried out using ever smoking controls (n=4784). Associations with %predicted FEV1 were tested in cases. We followed-up signals of interest (p<10(-5)) in independent samples from a subset of the UK Biobank population and also undertook a more powerful discovery study by meta-analysing the exome array data and UK Biobank data for variants represented on both arrays. RESULTS: Among the associated variants were two in regions previously unreported for COPD; a low frequency non-synonymous SNP in MOCS3 (rs7269297, pdiscovery=3.08×10(-6), preplication=0.019) and a rare SNP in IFIT3, which emerged in the meta-analysis (rs140549288, pmeta=8.56×10(-6)). In the meta-analysis of % predicted FEV1 in cases, the strongest association was shown for a splice variant in a previously unreported region, SERPINA12 (rs140198372, pmeta=5.72×10(-6)). We also confirmed previously reported associations with COPD risk at MMP12, HHIP, GPR126 and CHRNA5. No associations in novel regions reached a stringent exome-wide significance threshold (p<3.7×10(-7)). CONCLUSIONS: This study identified several associations with the risk of COPD and severity of airflow limitation, including novel regions MOCS3, IFIT3 and SERPINA12, which warrant further study.

Common variants in WFS1 confer risk of type 2 diabetes.

We studied genes involved in pancreatic beta cell function and survival, identifying associations between SNPs in WFS1 and diabetes risk in UK populations that we replicated in an Ashkenazi population and in additional UK studies. In a pooled analysis comprising 9,533 cases and 11,389 controls, SNPs in WFS1 were strongly associated with diabetes risk. Rare mutations in WFS1 cause Wolfram syndrome; using a gene-centric approach, we show that variation in WFS1 also predisposes to common type 2 diabetes.

Proof-of-concept evaluation of trough airway hyper-responsiveness following regular racemic or levosalbutamol in genotype-stratified steroid-treated persistent asthmatic patients.

Asthmatic patients receiving ICSs (inhaled corticosteroids) may take frequent add-on therapy with salbutamol despite on-demand prescription. Frequent salbutamol use can be detrimental in asthma. The isomeric formulation of salbutamol and the B2ADR (ß2 adrenoceptor) 16 genotype may also influence this phenomenon. We performed a randomized, double-blind, placebo-controlled, triple crossover, proof of concept trial comparing 2 weeks of regular therapy with inhaled racemic salbutamol [200 µg q.i.d. (four times daily)], levosalbutamol (100 µg q.i.d.) or placebo on trough methacholine PC20 [provocative concentration causing 20% fall in FEV1 (forced expiratory volume in 1 s)] 6 h post-dose (the primary outcome) in 30 persistent asthmatic patients (15 who were Arg16 homozygous and 15 who were Gly16 homozygous) all receiving ICSs. There was no worsening of AHR (airway hyper-responsiveness) at trough to methacholine after 2 weeks regular exposure to either racemic (P=0.53) or levosalbutamol (P=0.84) compared with placebo, nor between genotypes-as dd (doubling dilution) difference in methacholine PC20 from placebo [salbutamol/Arg16=0.36 dd [95% CI (confidence interval), -0.43, 1.15]; salbutamol/Gly16=0.01 dd (95% CI, -0.47, 0.49); levosalbutamol/Arg16=-0.01 dd (95% CI, -0.89, 0.87); and levosalbutamol/Gly16=0.28 dd (95% CI, -0.22, 0.77)]. Both active treatments improved morning PEF (peak expiratory flow) in Gly16 (P=0.04 overall) but not Arg16 (P=0.50 overall) patients, whereas evening PEF improved in both Gly16 (P<0.001 overall) and Arg16 (P=0.006 overall) patients. In conclusion, the regular exposure to either racemic or levosalbutamol for 2 weeks added to ICSs did not cause worsening of AHR at trough compared with placebo; with no difference seen between B2ADR 16 genotypes.

Tmem79/Matt is the matted mouse gene and is a predisposing gene for atopic dermatitis in human subjects.

BACKGROUND: Atopic dermatitis (AD) is a major inflammatory condition of the skin caused by inherited skin barrier deficiency, with mutations in the filaggrin gene predisposing to development of AD. Support for barrier deficiency initiating AD came from flaky tail mice, which have a frameshift mutation in Flg and also carry an unknown gene, matted, causing a matted hair phenotype. OBJECTIVE: We sought to identify the matted mutant gene in mice and further define whether mutations in the human gene were associated with AD. METHODS: A mouse genetics approach was used to separate the matted and Flg mutations to produce congenic single-mutant strains for genetic and immunologic analysis. Next-generation sequencing was used to identify the matted gene. Five independently recruited AD case collections were analyzed to define associations between single nucleotide polymorphisms (SNPs) in the human gene and AD. RESULTS: The matted phenotype in flaky tail mice is due to a mutation in the Tmem79/Matt gene, with no expression of the encoded protein mattrin in the skin of mutant mice. Matt(ft) mice spontaneously have dermatitis and atopy caused by a defective skin barrier, with mutant mice having systemic sensitization after cutaneous challenge with house dust mite allergens. Meta-analysis of 4,245 AD cases and 10,558 population-matched control subjects showed that a missense SNP, rs6684514, [corrected] in the human MATT gene has a small but significant association with AD. CONCLUSION: In mice mutations in Matt cause a defective skin barrier and spontaneous dermatitis and atopy. A common SNP in MATT has an association with AD in human subjects.

Environmental risk factors for respiratory infection and wheeze in young children: A multicentre birth cohort study.

INTRODUCTION: Respiratory infections and wheeze have a considerable impact on the health of young children and consume significant healthcare resources. We aimed to evaluate the effect of environmental factors on respiratory infections and symptoms in early childhood. METHODS: Environmental risk factors including: daycare attendance; breastfeeding; siblings; damp within the home; environmental tobacco smoke (ETS); child's bedroom flooring; animal exposure; road traffic density around child's home; and solid fuel pollution within home were assessed in children recruited to the GO-CHILD multicentre prospective birth cohort study. Follow-up information on respiratory infections (bronchiolitis, pneumonia, otitis media and cold or flu), wheeze and cough symptoms, healthcare utilisation and medication prescription was collected by postal questionnaires at 12 and 24 months. Log binomial and ordered logistic regression models were fitted to the data. RESULTS: Follow-up was obtained on 1344 children. Daycare was associated with increased odds of pneumonia (odds ratio [OR] = 2.39, 95% confidence interval [CI]: 1.04-5.49), bronchiolitis (OR = 1.40, 1.02-1.90), otitis media (OR = 1.68, 1.32-2.14) and emergency department attendance for wheeze (RR = 1.81, 1.17-2.80). Breastfeeding beyond 6 months was associated with a reduced odds of bronchiolitis (OR = 0.55, 0.39-0.77) and otitis media (OR = 0.75, 0.59-0.99). Siblings at home was associated with an increased odds of bronchiolitis (OR = 1.65, 1.18-2.32) and risk of reliever inhaler prescription (RR = 1.37, 1.02-1.85). Visible damp was associated with an increased odds of wheeze (OR = 1.85, 1.11-3.19), and risk of reliever inhaler (RR = 1.73, 1.04-2.89) and inhaled corticosteroid prescription (RR = 2.61, 1.03-6.59). ETS exposure was associated with an increased odds of primary care attendance for cough or wheeze (OR = 1.52, 1.11-2.08). Dense traffic around the child's home was associated with an increased odds of bronchiolitis (OR = 1.32, 1.08-2.29). CONCLUSION: Environmental factors likely influence the wide variation in infection frequency and symptoms observed in early childhood. Larger population studies are necessary to further inform and guide public health policy to decrease the burden of respiratory infections and wheeze in young children.

Robust association of the LPA locus with low-density lipoprotein cholesterol lowering response to statin treatment in a meta-analysis of 30 467 individuals from both randomized control trials and observational studies and association with coronary artery disease outcome during statin treatment.

OBJECTIVES: The LPA single-nucleotide polymorphism rs10455872 has been associated with low-density lipoprotein cholesterol (LDLc) lowering response to statins in several randomized control trials (RCTs) and is a known coronary artery disease (CAD) marker. However, it is unclear what residual risk of CAD this marker may have during statin treatment. METHODS: Using electronic medical records linked to the GoDARTS genotyped population, we identified over 8000 patients on statins in Tayside, Scotland. RESULTS: We replicated the findings of the RCTs, with the G allele of rs10455872 being associated with a 0.10 mmol/l per allele poorer reduction in LDLc in response to statin treatment, and conducted a meta-analysis with previously published RCTs (P = 1.46 × 10, n = 30 467). We showed an association between rs10455872 and CAD in statin-treated individuals and have replicated this finding in the Utrecht Cardiovascular Pharmacogenetics study (combined odds ratio 1.41, 95% confidence interval 1.17-1.68, P = 4.5 × 10, n = 8822) suggesting that statin treatment does not abrogate this well-established genetic risk for CAD. Furthermore, in a Cox proportional hazards model with LDLc measured time dependently, we demonstrated that the relationship between CAD and rs10455872 was independent of LDLc during statin treatment. CONCLUSION: Individuals with the G allele of rs10455872, which represents approximately one in seven patients, have a higher risk of CAD than the majority of the population even after treatment with statins; and therefore represent a vulnerable group requiring an alternative medication in addition to statin treatment.

Tailored second-line therapy in asthmatic children with the Arg(16) genotype.

The Arg(16) ß(2) receptor genotype confers increased susceptibility to exacerbations in asthmatic children taking regular LABA (long-acting ß(2) agonists). We therefore evaluated using montelukast as an alternative to salmeterol as tailored second-line asthma controller therapy in children expressing this susceptible genotype. A total of 62 persistent asthmatic children with the homozygous Arg16 genotype were randomized to receive salmeterol (50 µg, b.i.d.) or montelukast (5 or 10 mg, once daily) as an add-on to inhaled fluticasone for 1 year. School absences (the primary outcome) were reduced with montelukast compared with salmeterol {difference in score=-0.40 [95% CI (confidence interval), -0.22 to -0.58]; P=0.005}. Salbutamol use was also reduced with montelukast compared with salmeterol [difference in score=-0.47 (95% CI, -0.16 to -0.79); P<0.0001]. Greater improvements occurred in both symptom and quality of life scores with montelukast against salmeterol, whereas there was no difference in FEV(1) (forced expiratory volume in 1 s). In conclusion, montelukast may be suitable as tailored second-line controller therapy instead of salmeterol in asthmatic children expressing the susceptible Arg(16) genotype, a move towards a personalized medicine approach to management.

The prognostic value of adipose tissue fatty acids for incident cardiovascular disease: results from 3944 subjects in the Scottish Heart Health Extended Cohort Study.

AIMS: Dietary fats are routinely considered key determinants of cardiovascular risk, yet the scientific basis of this association has never been demonstrated using objective measures of fat intakes in a large prospective study in a general population. METHODS AND RESULTS: Adipose tissue was taken from 3944 participants, predominantly aged 40-59 years, in Scotland, 1984-87. Percentages of individual fatty acids were measured using gas chromatography. Over a median of 19.5 years, 870 incident cardiovascular disease (CVD) events occurred. Hazard ratios (HRs) were obtained from Cox models and the additional prognostic value, accounting for variables in the Framingham and ASSIGN CVD risk scores, were assessed using discrimination indices. Adjusting for age, sex, total and HDL-cholesterol, systolic blood pressure, smoking, hypertensive medication use, diabetes, socio-economic status and family history, the percentage of monounsaturated adipose tissue fatty acids had a positive log-linear relationship with incident CVD: the HR comparing risk between the fourth and first quartiles was 1.29 (95% confidence interval: 1.05, 1.59). n-3 polyunsaturated fat showed the reverse trend, the corresponding result being 0.77 (0.63, 0.94). These two composite variables improved the classification of incident CVD events by 1.0 and 6.4%, respectively, with only the latter being significant at the 5% level. CONCLUSIONS: A diet which is proportionately rich in polyunsaturated fat, as opposed to other fats, is expected to decrease the risk of CVD independently of the effects of common CVD risk factors, including social deprivation. Taking account of such diets improves the classification of future CVD events.

Mannose-binding lectin genotype is associated with respiratory disease in young children: A multicenter cohort study.

BACKGROUND: Mannose-binding lectin (MBL) is an important component of the innate immune system. Polymorphisms in the MBL2 gene and promoter region are directly associated with MBL-deficiency. We sought to determine the association between MBL genotype on the frequency of common childhood respiratory infections, respiratory symptoms, and atopic outcomes in early childhood. METHODS: MBL2 gene variants were analyzed in newborns recruited to the GO-CHILD multicenter prospective cohort study. Follow-up for respiratory infection and atopy diagnoses and symptoms, healthcare utilization, and medication prescription were conducted by postal questionnaires at 12 and 24 months. RESULTS: Genotyping and follow-up were completed in 1004 children. Genotypes associated with MBL-deficiency were associated with an increased risk of bronchiolitis (relative risk [RR] 1.95, 95% confidence interval [CI] 1.33-2.85) and pneumonia (RR 2.46, 95% CI 1.16-5.22). MBL-deficient genotypes were associated with an increased risk of wheeze with shortness of breath episodes (RR 1.22, 95% CI 1.04-1.43), emergency department attendance (RR 1.90 95% CI 1.13-3.19), and hospital admission (RR 2.01, 95% CI 1.04-3.89) for wheeze. MBL-deficient genotypes were associated with a reduced risk of developing atopic dermatitis (RR 0.72, 95% CI 0.53-0.98). CONCLUSION: The positive association between MBL-deficient genotypes and bronchiolitis and pneumonia, as well as a severe wheeze phenotype in some young children, supports the hypothesis that MBL is an important component of innate immunity in the vulnerable period before the maturation of the adaptive immune system. Identification of disease-modifying genotypes may help target preventative strategies in high-risk infants.