Genetic evidence supports the development of SLC26A9 targeting therapies for the treatment of lung disease.

Over 400 variants in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) are CF-causing. CFTR modulators target variants to improve lung function, but marked variability in response exists and current therapies do not address all CF-causing variants highlighting unmet needs. Alternative epithelial ion channel/transporters such as SLC26A9 could compensate for CFTR dysfunction, providing therapeutic targets that may benefit all individuals with CF. We investigate the relationship between rs7512462, a marker of SLC26A9 activity, and lung function pre- and post-treatment with CFTR modulators in Canadian and US CF cohorts, in the general population, and in those with chronic obstructive pulmonary disease (COPD). Rs7512462 CC genotype is associated with greater lung function in CF individuals with minimal function variants (for which there are currently no approved therapies; p = 0.008); and for gating (p = 0.033) and p.Phe508del/ p.Phe508del (p = 0.006) genotypes upon treatment with CFTR modulators. In parallel, human nasal epithelia with CC and p.Phe508del/p.Phe508del after Ussing chamber analysis of a combination of approved and experimental modulator treatments show greater CFTR function (p = 0.0022). Beyond CF, rs7512462 is associated with peak expiratory flow in a meta-analysis of the UK Biobank and Spirometa Consortium (p = 2.74 × 10-44) and provides p = 0.0891 in an analysis of COPD case-control status in the UK Biobank defined by spirometry. These findings support SLC26A9 as a therapeutic target to improve lung function for all people with CF and in individuals with other obstructive lung diseases.

Outcomes of Cystic Fibrosis Screening-Positive Infants With Inconclusive Diagnosis at School Age.

BACKGROUND AND OBJECTIVES: Cystic fibrosis (CF) screen-positive infants with an inconclusive diagnosis (CFSPID) are infants in whom sweat testing and genetic analysis does not resolve a CF diagnosis. Lack of knowledge about the health outcome of these children who require clinical follow-up challenges effective consultation. Early predictive biomarkers to delineate the CF risk would allow a more targeted approach to these children. METHODS: Prospective, longitudinal, multicenter, Canada-wide cohort study of CF positive-screened newborns with 1 to 2 cystic fibrosis transmembrane conductance regulator gene variants, of which at least 1 is not known to be CF-causing and/or a sweat chloride between 30 and 59 mmol/L. These were monitored for conversion to a CF diagnosis, pulmonary, and nutritional outcomes. RESULTS: The mean observation period was 7.7 (95% confidence interval 7.1 to 8.4) years. A CF diagnosis was established for 24 of the 115 children with CFSPID (21%) either because of reinterpretation of the cystic fibrosis transmembrane conductance regulator genotype or because of increase in sweat chloride concentration ≥60 mmol/L. An initial sweat chloride of ≥40 mmol/l predicted conversion to CF on the basis of sweat testing. The 91 remaining children with CFSPID were pancreatic sufficient and showed normal growth until school age. Pulmonary function as well as lung clearance index in a subgroup of children with CFSPID were similar to that of healthy controls. CONCLUSIONS: Children with CFSPID have good nutritional and pulmonary outcomes at school age, but rates of reclassifying the diagnosis are high. The initial sweat chloride test can be used as a biomarker to predict the risk for CF in CFSPID.

Cystic fibrosis-related diabetes onset can be predicted using biomarkers measured at birth.

PURPOSE: Cystic fibrosis (CF), caused by pathogenic variants in the CF transmembrane conductance regulator (CFTR), affects multiple organs including the exocrine pancreas, which is a causal contributor to cystic fibrosis-related diabetes (CFRD). Untreated CFRD causes increased CF-related mortality whereas early detection can improve outcomes. METHODS: Using genetic and easily accessible clinical measures available at birth, we constructed a CFRD prediction model using the Canadian CF Gene Modifier Study (CGS; n = 1,958) and validated it in the French CF Gene Modifier Study (FGMS; n = 1,003). We investigated genetic variants shown to associate with CF disease severity across multiple organs in genome-wide association studies. RESULTS: The strongest predictors included sex, CFTR severity score, and several genetic variants including one annotated to PRSS1, which encodes cationic trypsinogen. The final model defined in the CGS shows excellent agreement when validated on the FGMS, and the risk classifier shows slightly better performance at predicting CFRD risk later in life in both studies. CONCLUSION: We demonstrated clinical utility by comparing CFRD prevalence rates between the top 10% of individuals with the highest risk and the bottom 10% with the lowest risk. A web-based application was developed to provide practitioners with patient-specific CFRD risk to guide CFRD monitoring and treatment.

Immunoreactive trypsinogen levels in newborn screened infants with an inconclusive diagnosis of cystic fibrosis.

BACKGROUND: Newborn screening (NBS) for cystic fibrosis (CF) not only identifies infants with a diagnosis of CF, but also those with an uncertain diagnosis of cystic fibrosis (CF), i.e. CF transmembrane conductance regulator (CFTR)-related metabolic syndrome (CRMS) or CF screen positive inconclusive diagnosis (CFSPID). These infants have an uncertain long-term outcome and it is currently unclear around time of diagnosis, which infants are at higher risk of later fulfilling a CF diagnosis. In this study, we hypothesised that immunoreactive trypsinogen (IRT) levels, used in NBS as a marker of pancreatic disease and function, may reflect the degree of CFTR dysfunction in each individual and therefore would help to identify those with CRMS/CSPID who are later at risk for meeting the criteria of CF. METHODS: In this longitudinal, prospective study, infants with CRMS/CFSPID and CF were recruited and followed in 9 CF clinics (Canada and Italy). We compared NBS IRT levels between CF and CRMS/CFSPID, and between children with CRMS/CFSPID→CF and CRMS/CFSPID→CRMS/CFSPID during the period of June 2007 to April 2016. RESULTS: Ninety eight CRMS/CFSPID and 120 CF subjects were enrolled. During the study period, 14 (14.3%) CRMS/CFSPID subjects fulfilled the diagnostic criteria for CF (CRMS/CFSPID→CF), while the diagnosis remained uncertain (CRMS/CFSPID→ CRMS/CFSPID) in 84 (85.7%) subjects. Significantly higher NBS IRT concentrations (ng/ml) were present in CF than CRMS/CFPSID (median (interquartile range): 143.8 (99.8-206.2) vs. 75.0 (61.0-105.9); P < 0.0001). Infants with CRMS/CFSPID→CF (n = 14) had significantly higher NBS IRT concentrations (ng/ml) than CRMS/CFSPID→ CRMS/CFSPID (n = 83) (median (interquartile range): 108.9 (72.3-126.8) vs. 73.7(60.0-96.0); P = 0.02). CONCLUSIONS: Amongst infants who tested positive on NBS for CF, there is a gradation of elevated NBS IRT concentrations. Infants with CF have higher NBS IRT levels than CRMS/CFPSID, and higher NBS IRT concentrations were present in infants with CRMS/CFSPID→CF than CRMS/CFSPID→ CRMS/CFSPID. NBS IRT concentrations, in concert with other factors, may have the potential to predict the likelihood of CF amongst infants with CRMS/CFSPID.

The impact of electronic consultation on a Canadian tertiary care pediatric specialty referral system: A prospective single-center observational study.

BACKGROUND: Champlain BASE™ (Building Access to Specialists through eConsultation) is a web-based asynchronous electronic communication service that allows primary-care- practitioners (PCPs) to submit "elective" clinical questions to a specialist. For adults, PCPs have reported improved access and timeliness to specialist advice, averted face-to-face specialist referrals in up to 40% of cases and high provider satisfaction. OBJECTIVE: To determine whether the expansion of eConsult to a pediatric setting would result in similar measures of improved healthcare system process and high provider acceptance reported in adults. DESIGN: Prospective observational cohort study. SETTING: Single Canadian tertiary-care academic pediatric hospital (June 2014-16) servicing 1.2 million people. PARTICIPANTS: 1. PCPs already using eConsult. 2.Volunteer pediatric specialists provided services in addition to their regular workload. 3.Pediatric patients (< 18 years-old) referred for none-acute care conditions. MAIN OUTCOMES AND MEASURES: Specialty service utilization and access, impact on PCP course-of-action and referral-patterns and survey-based provider satisfaction data were collected. RESULTS: 1064 eConsult requests from 367 PCPs were answered by 23 pediatric specialists representing 14 specialty-services. The top three specialties represented were: General Pediatrics 393 cases (36.9%), Orthopedics 162 (15.2%) and Psychiatry 123 (11.6%). Median specialist response time was 0.9 days (range <1 hour-27 days), most consults (63.2%) required <10minutes to complete and 21/21(100%) specialist survey-respondents reported minimal workload burden. For 515/1064(48.4%) referrals, PCPs received advice for a new or additional course of action; 391/1064(36.7%) referrals resulted in an averted face-to-face specialist visit. In 9 specialties with complete data, the median wait-time was significantly less (p<0.001) for an eConsult (1 day, 95%CI:0.9-1.2) compared with a face-to-face referral (132 days; 95%CI:127-136). The majority (>93.3%) of PCPs rated eConsult as very good/excellent value for both patients and themselves. All specialist survey-respondents indicated eConsult should be a continued service. CONCLUSIONS AND RELEVANCE: Similar to adults, eConsult improves PCP access and timeliness to elective pediatric specialist advice and influences their care decisions, while reporting high end-user satisfaction. Further study is warranted to assess impact on resource utilization and clinical outcomes.

Quantitative tissue polymerase chain reaction for Epstein-Barr virus in pediatric solid organ recipients.

BACKGROUND: Infections caused by herpes virus, in particular, Epstein-Barr virus (EBV), remain a major challenge in solid organ transplantation. Little is known about the significance of tissue EBV load. METHODS: Twenty-three tissue biopsy specimens (19 kidney, 3 gastrointestinal, and 1 tonsil specimen) and 2 bronchoalveolar lavage specimens from 14 pediatric transplant recipients (10 kidney, 3 liver, 1 combined transplant) were subject to tissue EBV polymerase chain reaction (PCR) semiquantitative analysis and enzyme-linked immunosorbent assay (ELISA) methods. Results of biopsies were correlated with clinical data. RESULTS: Five of 14 patients had clinically diagnosed EBV disease: 2 patients presented with a septic picture with multiorgan failure and pneumonitis; 1 patient had mononucleosis; 1 patient had an increase in serum creatinine level, lymphadenopathy, and chronic fatigue; and 1 patient had EBV nephritis. These 5 patients underwent 12 biopsies at the time of clinically active infection; 8 biopsies had positive results (up to 111 copies/10 microL of extracted DNA). Conversely, 1 of the remaining 13 tissue biopsy specimens from asymptomatic patients had positive results on ELISA, but undetectable viral load, whereas 8 patients had a positive EBV immunoglobulin G titer with historic evidence of EBV replication in the blood. No patient without evidence of EBV had positive EBV tissue PCR results. CONCLUSION: Increased EBV load was found in more than 50% of patients, pointing to a previously underrecognized importance of EBV detection in tissues from transplant recipients. The presence of EBV in tissue correlated with the presence of viremia, whereas tissue PCR had 100% specificity. EBV load should be included in biopsy evaluation.