Prevalence of tracheobronchomalacia is higher than previously reported in children with cystic fibrosis.

BACKGROUND: Tracheobronchomalacia (TBM) is estimated to be present in 1 in 2100 children. Previous reports suggest the prevalence is higher in children with cystic fibrosis (CF). This has clinical implications with potential to influence airway clearance and lung health. AIM: To determine the prevalence and clinical associations of TBM in Western Australian children with CF. METHODS: Children with CF born between 2001 and 2016 were included. Operation reports from bronchoscopies performed until the age of 4 were retrospectively reviewed. Data were collected on the presence, persistence defined as a repeat diagnosis, and severity of TBM. Data on genotype, pancreatic status, and symptoms at CF diagnosis were extracted from the medical record. Associations between categorical variables were compared using χ2 and Fisher's exact test. RESULTS: Of 167 children (79 male), 68 (41%) were diagnosed with TBM at least once, with TBM persistent in 37 (22%) and severe in 31 (19%). TBM was significantly associated with pancreatic insufficiency (χ2 = 7.874, p < 0.05, odds ratio [OR] 3.4), delta F508 gene mutation (χ2 = 6.489, p < 0.05, OR 2.3), and a presentation of meconium ileus (χ2 = 8.615, p < 0.05, OR 5.0). Severe malacia was less likley in females (χ2 = 4.523, p < 0.05, OR 0.42) . No significant relationship was found with respiratory symptoms at the time of CF diagnosis (χ2 = 0.742, p = 0.39). CONCLUSIONS: TBM was common in this group of children under the age of 4 with CF. A high index of suspicion for airway malacia should be considered in children with CF, particularly those who present with meconium ileus and have gastrointestinal symptoms at diagnosis.

High-quality read-based phasing of cystic fibrosis cohort informs genetic understanding of disease modification.

Phasing of heterozygous alleles is critical for interpretation of cis-effects of disease-relevant variation. We sequenced 477 individuals with cystic fibrosis (CF) using linked-read sequencing, which display an average phase block N50 of 4.39 Mb. We use these samples to construct a graph representation of CFTR haplotypes, demonstrating its utility for understanding complex CF alleles. These are visualized in a Web app, CFTbaRcodes, that enables interactive exploration of CFTR haplotypes present in this cohort. We perform fine-mapping and phasing of the chr7q35 trypsinogen locus associated with CF meconium ileus, an intestinal obstruction at birth associated with more severe CF outcomes and pancreatic disease. A 20-kb deletion polymorphism and a PRSS2 missense variant p.Thr8Ile (rs62473563) are shown to independently contribute to meconium ileus risk (p = 0.0028, p = 0.011, respectively) and are PRSS2 pancreas eQTLs (p = 9.5 × 10-7 and p = 1.4 × 10-4, respectively), suggesting the mechanism by which these polymorphisms contribute to CF. The phase information from linked reads provides a putative causal explanation for variation at a CF-relevant locus, which also has implications for the genetic basis of non-CF pancreatitis, to which this locus has been reported to contribute.

Cystic fibrosis with liver involvement in adults has a benign course. Results from a tertiary referral center cohort.

BACKGROUND: Cystic Fibrosis Liver Disease is a poorly understood entity, especially in adults, in terms of its real prevalence, natural history and diagnostic criteria, despite being the most important extrapulmonary cause of mortality. The aim was to evaluate the prevalence, characteristics and potential risk factors of liver disease in adults with cystic fibrosis, according to two diagnostic criteria accepted in the scientific literature. METHODS: Patients were recruited in a tertiary referral hospital, and laboratory, ultrasound, non-invasive liver fibrosis tests (AST to Platelet Ratio Index; Fibrosis-4 Index) and transient elastography (Fibroscan) were performed. The proportion of patients with liver disease according to the Debray and Koh criteria were evaluated. RESULTS: 95 patients were included, 48 (50.5%) females, with a mean age of 30.4 (28.6-32.2) years. According to the Debray criteria, 6 (6.3%) patients presented liver disease. According to the Koh criteria, prevalence increased up to 8.4%, being statistically different from the 25% value described in other published series (p = 0.005). Seven (7.5%) presented ultrasonographic chronic liver disease. Eleven (13%) presented liver fibrosis according to the APRI score; 95 (100%) had a normal FIB-4 value. Mean liver stiffness value was 4.4 (4.1-4.7) kPa. FEV1 (OR=0.16, p 0.05), meconium ileus (OR=14.16, p 0.002), platelets (Pearson coefficient -0.25, p 0.05) and younger age (Pearson coefficient -0.19, p 0.05) were risk factors. CONCLUSIONS: Prevalence and severity of liver disease in adult cystic fibrosis patients were lower than expected. Meconium ileus, platelets, age and respiratory function were confirmed as risk factors associated to cystic fibrosis liver disease.

Meconium Ileus, Distal Intestinal Obstruction Syndrome, and Other Gastrointestinal Pathology in the Cystic Fibrosis Patient.

Cystic fibrosis is an autosomal-recessive defect in the cystic fibrosis transmembrane conductance regulator (CFTR) gene located on chromosome 7 that affects 1 in 2500 live White births. Defects in the gene lead to abnormally thick secretions causing chronic obstruction in the respiratory and gastrointestinal tracts. Common gastrointestinal pathology in children with cystic fibrosis includes meconium ileus in infancy and distal intestinal obstruction syndrome in childhood and exocrine pancreatic insufficiency, constipation, and rectal prolapse. This article describes the presentation, diagnosis, and management of these conditions in patients with cystic fibrosis, from birth to adulthood.

Disease-modifying genetic factors in cystic fibrosis.

PURPOSE OF REVIEW: To compile data from the past 10 years regarding the role of modifying genes in cystic fibrosis (CF). RECENT FINDINGS: CF is a model disease for understanding of the action of modifying genes. Although it is a monogenic (CFTR) autosomal recessive disease, CF presents with wide phenotypic variability. In CF, variability occurs with different intensity among patients by each organ, being organ-specific, resulting from the mutual interaction of environmental and genetic factors, including CFTR mutations and various other genes, most of which are associated with inflammatory processes. In individuals, using precision medicine, gene modification studies have revealed individualized responses to drugs depending on particular CFTR mutations and modifying genes, most of which are alternative ion channels. SUMMARY: Studies of modifying genes in CF allow: understanding of clinical variability among patients with the same CFTR genotype; evaluation of precision medicine; understanding of environmental and genetic effects at the organ level; understanding the involvement of genetic variants in inflammatory responses; improvements in genetic counseling; understanding the involvement of genetic variants in inflammatory responses in lung diseases, such as asthma; and understanding the individuality of the person with the disease.

Long-term intestinal obstruction sequelae and growth in children with cystic fibrosis operated for meconium ileus: expectancies and surprises.

BACKGROUND/PURPOSE: In the few studies on intestinal complications and growth of cystic fibrosis (CF) patients with a history of meconium ileus (MI), operated MI has not been investigated separately. We aimed to investigate the incidence of long-term intestinal obstruction sequelae [constipation, distal intestinal obstruction syndrome (DIOS)] and growth in CF patients operated for MI. METHODS: Retrospective study (1989-2016) including operative diagnoses and procedures, constipation and DIOS events, yearly Body Mass Index (BMI) measurements. Outcomes were examined in subgroups operated for MI only and for MI with atresia and/or volvulus. RESULTS: Of 49 patients followed-up for 15 (mean) years, 5 (10.2%) developed constipation and 14 (28.6%) DIOS. BMI was within normal percentiles in 53 patients over a 10-year follow-up. MI only and MI with atresia and/or volvulus did not differ in constipation and/or DIOS incidence (11/34 vs. 7/15, p=0.39) or in BMI (p=0.47). Cases with ileocecal valve resection (ICV-R) showed lower constipation and/or DIOS incidence than those without ICV-R (0/6 vs. 11/28, p=0.02) and no different BMI (p>0.05). CONCLUSIONS: CF patients operated for MI were in long-term risk for constipation/DIOS; their growth was normal. Interestingly, underlying atresia/volvulus neither increased constipation/DIOS risk nor affected growth. Strikingly, ICV-R showed no constipation/DIOS risk and no impact on growth. TYPE OF STUDY: Retrospective comparative study. LEVEL OF EVIDENCE: III.

Body composition and lung function in children with cystic fibrosis and meconium ileus.

The aim of this study was to explore whether history of meconium ileus (MI) at birth in children and adolescents with cystic fibrosis (CF) adversely affects body composition and lung function in later life. Data of children and adolescents with CF who underwent spirometry and DXA as part of their routine care were analyzed. Associations between MI (explanatory variable) and areal bone mineral density (total body less head-TBLH aBMD), lean tissue mass (LTM), and fat mass (FM) (outcomes) were assessed using general linear models. Potential relationships of TBLH aBMD, LTM, and FM with FEV1 (additional outcome) were also explored. One hundred and one subjects with CF (mean age 14 ± 3 years) were included, 19 (18.8%) of whom had history of MI. Negative associations were demonstrated between history of MI and FEV1 (P = 0.04), TBLH aBMD (P = 0.03), and FM (P < 0.01) but not between history of MI and LTM (P = 0.07) after adjustment for other variables. Lung function was positively associated with TBLH aBMD (P < 0.01) and LTM (P = 0.02) but not with FM (P = 0.20). CONCLUSION: Among children and adolescents with CF, those with history of MI have lower bone mineral density, FM, and lung function. What is Known: • Among children and adolescents with cystic fibrosis, those with history of meconium ileus in the neonatal period are at risk of having lower body mass index percentile and FEV 1 percent predicted. What is New: • Children and adolescents with cystic fibrosis and history of meconium ileus have decreased bone mineral density and fat mass compared to patients without such history. • Lower lung function in children with MI coexists with suboptimal bone mineral density.