The impact of improved nutritional status on health-related quality of life (HRQOL) is unknown for children with cystic fibrosis (CF).
Associations between nutritional status and HRQOL were examined over 2 years in 95 children, aged 9–19 years, who were followed in the Wisconsin Newborn Screening Project. HRQOL was assessed using the Cystic Fibrosis Questionnaire (CFQ). Associations between height z-score (HtZ), BMI z-score (BMIZ) and seven CFQ dimensions were evaluated.
Mean values of at least 80 were observed for all CFQ dimensions except respiratory symptoms and treatment burden. Treatment burden was significantly worse in patients with meconium ileus (57) compared to pancreatic insufficient (65) and sufficient (78) subjects, p<0.0001. HtZ and BMIZ were positively associated with physical functioning and body image (p<0.05).
Better nutritional status was associated with increased HRQOL scores. Early diagnosis through newborn screening and improved nutrition provides an opportunity to enhance quality of life and body image perception.
Rationale: Previous studies of risk factors for progression of lung disease in cystic fibrosis (CF) have suffered from limitations that preclude a comprehensive understanding of the determinants of CF lung disease throughout childhood. The epidemiologic component of the 27-year Wisconsin Randomized Clinical Trial of CF Neonatal Screening Project (WI RCT) afforded us a unique opportunity to evaluate the significance of potential intrinsic and extrinsic risk factors for lung disease in children with CF.
Objectives: Describe the most important intrinsic and extrinsic risk factors for progression of lung disease in children with CF.
Methods: Variables hypothesized at the onset of the WI RCT study to be determinants of the progression of lung disease and potential risk factors previously identified in the WI RCT study were assessed with multivariable generalized estimating equation models for repeated measures of chest radiograph scores and pulmonary function tests in the WI RCT cohort.
Measurements and Main Results: Combining all patients in the WI RCT, 132 subjects were observed for a mean of 16 years and contributed 1,579 chest radiographs, and 1,792 pulmonary function tests. The significant determinants of lung disease include genotype, poor growth, hospitalizations, meconium ileus, and infection with mucoid Pseudomonas aeruginosa. The previously described negative effect of female sex was not seen.
Conclusions: Modifiable extrinsic risk factors are the major determinants of progression of lung disease in children with CF. Better interventions to prevent or treat these risk factors may lead to improvements in lung health for children with CF.
pulmonary function test; chest X-ray; newborn screening; nutrition; sex
CDC's Newborn Screening Quality Assurance Program collaborated with several U.S. Cystic Fibrosis Care Centers to collect specimens for development of a molecular CFTR proficiency testing program using dried-blood spots for newborn screening laboratories.
Adult and adolescent patients or carriers donated whole blood that was aliquoted onto filter paper cards. Five blind-coded specimens were sent to participating newborn screening laboratories quarterly. Proficiency testing results were evaluated based on presumptive clinical assessment. Individual evaluations and summary reports were sent to each participating laboratory and technical consultations were offered if incorrect assessments were reported.
The current CDC repository contains specimens with 39 different CFTR mutations. Up to 45 laboratories have participated in the program. Three years of data showed that correct assessments were reported 97.7% of the time overall when both mutations could be determined. Incorrect assessments that could have lead to a missed case occurred 0.9% of the time, and no information was reported 1.1% of the time due to sample failure.
Results show that laboratories using molecular assays to detect CFTR mutations are performing satisfactorily. The programmatic results presented demonstrate the importance and complexity of providing proficiency testing for DNA-based assays.
Newborn Screening; Proficiency Testing; Cystic Fibrosis; DNA; mutations
There has been great variation and uncertainty about how many and what CFTR mutations to include in cystic fibrosis (CF) newborn screening algorithms, and very little research on this topic using large populations of newborns.
We reviewed Wisconsin screening results for 1994–2008 to identify an ideal panel.
Upon analyzing approximately 1 million screening results, we found it optimal to use a 23 CFTR mutation panel as a second tier when an immunoreactive trypsinogen (IRT)/DNA algorithm was applied for CF screening. This panel in association with a 96th percentile IRT cutoff gave a sensitivity of 97.3%, but restricting the DNA tier to F508del was associated with 90% (P<.0001).
Although CFTR panel selection has been challenging, our data show that a 23 mutation method optimizes sensitivity and is practically advantageous. The IRT cutoff value, however, is actually more critical than DNA in determining CF newborn screening sensitivity.
Cystic Fibrosis Transmembrane Conductance Regulator; immunoreactive trypsinogen; sensitivity
Because cystic fibrosis can be difficult to diagnose and treat early, newborn screening programs have rapidly developed nationwide but methods vary widely. We therefore investigated the costs and consequences or specific outcomes of the 2 most commonly used methods.
With available data on screening and follow-up, we used a simulation approach with decision trees to compare immunoreactive trypsinogen (IRT) screening followed by a second IRT test against an IRT/DNA analysis. By using a Monte Carlo simulation program, variation in the model parameters for counts at various nodes of the decision trees, as well as for costs, are included and applied to fictional cohorts of 100 000 newborns. The outcome measures included the numbers of newborns given a diagnosis of cystic fibrosis and costs of screening strategy at each branch and cost per newborn.
Simulations revealed a substantial number of potential missed diagnoses for the IRT/IRT system versus IRT/DNA. Although the IRT/IRT strategy with commonly used cutoff values offers an average overall cost savings of $2.30 per newborn, a breakdown of costs by societal segments demonstrated higher out-of-pocket costs for families. Two potential system failures causing delayed diagnoses were identified relating to the screening protocols and the follow-up system.
The IRT/IRT screening algorithm reduces the costs to laboratories and insurance companies but has more system failures. IRT/DNA offers other advantages, including fewer delayed diagnoses and lower out-of-pocket costs to families.
cystic fibrosis; immunoreactive trypsinogen; DNA; newborn screening; costs; sensitivity
This study examined the convergent validity of health-related quality of life (HRQOL) reported by patients with cystic fibrosis compared with their parents’ reports and objective pulmonary measures across three time points.
Ninety-two children (8–13 years) and adolescents (14–18 years) with CF and their parents completed Cystic Fibrosis Questionnaires to examine concordance with Wisconsin Chest X-Ray (WCXR) scores and pulmonary function tests, e.g., forced expiratory volume at one second (FEV1), and parent-child/adolescent concordance across multiple HRQOL domains. Concordance was analyzed relative to patient age and gender.
Parent reports were closely aligned with WCXR scores, while patient reports were more closely aligned with FEV1. Adolescents and parents of both age groups had more HRQOL domains concordant with pulmonary health measures than did child self-reports. Parent-child concordance was inversely related to child age, particularly with male adolescents. Children generally reported better HRQOL than parents. Male adolescents and their parents were more likely to have significantly discordant HRQOL scores than female adolescents and their parents. Male and female adolescents reported higher HRQOL than their parents reported for all but Vitality and Health Perception domains. Younger male children showed concordance with their parents on five of seven domains.
Parent-child/adolescent discordance on HRQOL was consistent with normative child development expectations. Findings underscore the value of enlisting perspectives from parents as well as children regarding HRQOL.
The optimal strategy for monitoring cystic fibrosis (CF) lung disease in infancy remains unclear.
To describe longitudinal associations between infant pulmonary function tests (iPFTs), chest radiograph (CXR) scores and other characteristics.
CF patients ≤ 24 months old were enrolled in a 10-center study evaluating iPFTs 4 times over a year. CXRs ~1 year apart were scored with the Wisconsin and Brasfield systems. Associations of iPFT parameters with clinical characteristics were evaluated with mixed effects models.
The 100 participants contributed 246 acceptable flow/volume (FEV0.5, FEF75) and 303 acceptable functional residual capacity (FRC) measurements and 171 CXRs. Both Brasfield and Wisconsin CXR scores worsened significantly over the 1 year interval. Worse Wisconsin CXR scores and S. aureus were both associated with hyperinflation (significantly increased FRC) but not with diminished FEV0.5 or FEF75. Parent-reported cough was associated with significantly diminished FEF75 but not with hyperinflation.
In this infant cohort in whom we previously reported worsening in average lung function, CXR scores also worsened over a year. The significant associations detected between both Wisconsin CXR score and S. aureus and hyperinflation, as well as between cough and diminished flows, reinforce the ability of iPFTs and CXRs to detect early CF lung disease.
cystic fibrosis; imaging; infants; lung function
Chronic pulmonary infection with Pseudomonas aeruginosa (PA) is responsible for significant morbidity and mortality in cystic fibrosis (CF). Because of the limited studies evaluating early exposure and the progression of genetic variability of PA, our goal was to assess PA in young children with CF followed in two clinic types.
A total of 39 infants with CF diagnosed through newborn screening were randomly assigned to either a segregated (PA-free) or mixed (PA-positive) clinic at two different CF centers, one of which replaced an older, mixed clinic where nosocomial acquisition was suspected. Oropharyngeal (OP) swab cultures were examined with subsequent genotyping to characterize the strains of PA isolated.
We found that 13/21 segregated clinic patients and 14/18 mixed clinic patients showed positive PA, with median acquisition ages of 3.3 and 2.2 years, respectively (P=0.57). The median time to PA acquisition, however, was significantly longer in the new clinic with proper hygiene precautions compared to an old site (5.0 vs 1.7 years, P<0.001). The majority of subjects isolated a single genotype of PA or AP-PCR types during the study period with 8 subjects clearing the isolate after only one positive culture. The development of chronic colonization yielded the predominance of a single major genotype or AP-PCR type.
Segregation of infants and young children with CF in PA negative or PA positive clinics did not alter the time to first PA isolation in this randomized assessment of facilities with hygienic precautions. During the early infection period where PA is first isolated in young children with CF, patients cleared different PA strains until a predominant strain established permanent colonization.
Pseudomonas aeruginosa; cystic fibrosis; newborn screening; arbitrarily primed polymerase chain reaction; genotype; segregated clinic; integrated clinic
A comparison of the longitudinal progression of lung disease in cystic fibrosis patients identified through newborn screening (NBS) in cohorts located in two different countries has never been performed and was the primary objective of this study.
The study included 56 patients in Brittany diagnosed through NBS between 1989 and 1994 and 69 similar patients in Wisconsin between 1985 and 1994. The onset and progression of lung disease was radiographically quantified using the Wisconsin Chest X-ray (WCXR) scoring system. A single pediatric pulmonologist blinded to all identifiers scored the films.
Generalized estimating equation analyses adjusted for age, genotype, sex, pancreatic insufficiency, and meconium ileus showed worse WCXR scores in Brittany patients compared to Wisconsin patients (average score difference=4.48; p<0.001). Percent predicted FEV1 was also worse among Brittany patients (p<0.001).
The finding of milder radiographically-quantified lung disease using the WCXR scoring system, as well as better FEV1 values, may be explained by variations in nutrition, environmental exposures, or healthcare delivery.
cystic fibrosis; Wisconsin; Brittany; chest x-ray; infection; genotype
Progression of lung disease is a major event in children with cystic fibrosis (CF), but regional differences in its evolution are unclear. We hypothesized that regional differences occur beginning in early childhood. We examined this issue by evaluating 132 patients followed in the Wisconsin Neonatal Screening Project between 1985 and 2010. We scored chest x-rays obtained every 1–2 years with the Wisconsin chest x-ray system, in which we divided the lungs into quadrants, and gave special attention to ratings for bronchiectasis (BX) and nodular/branching opacities. We compared the upper and lower quadrant scores, and upper right and left quadrant scores, as patients aged using a multivariable generalized estimation equation (GEE) model. We did a confirmatory analysis for a subset of 81 patients with chest computerized tomography (CT) images obtained in 2000 and scored using the Brody scoring system. The chest x-ray analysis shows that the upper quadrants have higher BX (p<0.001) and nodular/branching opacities (p<0.001) scores than the lower quadrants. CT analysis likewise reveals that the upper quadrants have more BX (p=0.02). Patients positive for mucoid PA showed significantly higher BX scores than patients with nonmucoid PA (p= 0.001). Chest x-ray scoring also revealed that the upper right quadrant has more BX (p< 0.001) than the upper left quadrant, and CT analysis was again confirmatory (p< 0.001). We conclude that pediatric patients with CF develop more severe lung disease in the upper lobes than the lower lobes in association with mucoid PA infections and also have more severe lung disease on the right side than on the left side in the upper quadrants. A variety of potential explanations such as aspiration episodes may be clinically relevant and provide insights regarding therapies.
cystic fibrosis; lung disease; bronchiectasis; upper lobes; mucoid Pseudomonas aeruginosa
Chest CT scans detect structural abnormalities in children with cystic fibrosis (CF), even when pulmonary function tests (PFTs) are normal. The use of chest CT is limited in clinical practice, because of concerns over expense, increased resource utilization, and radiation exposure. Quantitative chest radiography scores are useful in detecting mild lung disease, but whether they are sensitive to the presence of CT scan abnormalities has not been evaluated.
To determine in a cross-sectional study if quantitative chest radiography is a more sensitive marker of chest CT abnormalities than other lung disease surrogates.
Brody chest CT scores were calculated for 81 children enrolled in the Wisconsin CF Neonatal Screening Project. We determined the sensitivity for Wisconsin (WCXR) and Brasfield (BCXR) chest radiography scores, PFTs, positive cultures for P. aeruginosa (PA), and parental report of symptoms to detect a Brody score worse than the median score for study participants.
Measurements and Main Results
The mean FEV1 for the study population was 91% predicted. Abnormal WCXR and BCXR scores had the highest sensitivity to detect a chest CT score worse than the median; abnormal PFTs, parental report of symptoms, and the presence of PA had much lower sensitivity (p<0.001).
In this cross sectional study, quantitative chest radiography has excellent sensitivity to detect an abnormal chest CT and may have a role in monitoring lung disease progression in children with CF.
Chest x-ray; quantitative radiography; pulmonary function
Newborn screening (NBS) enables early treatment and some consider it a natural vehicle for genetic screening. Bioethicists argue for caution since families of carrier infants can develop psychosocial complications. This paper describes methods and feasibility of our statewide project for quality improvement of communication and psychosocial outcomes after NBS.
When NBS identifies carrier status for cystic fibrosis or sickle cell, we contact primary care providers (PCPs), answer questions, and invite them to rehearse informing the parents. Three months later we telephone parents, assess knowledge and psychosocial outcomes, provide counseling, and assist with self-referral to further resources. Afterwards, anonymous evaluation surveys are provided.
Birthing facilities provided accurate PCP names for 73% of 817 infants meeting inclusion criteria; we identified PCPs for 21% more. We reached 47.3% of PCPs in time to invite a rehearsal; 60% of these accepted. We successfully called 50.2% of eligible parents; 61% recalled a PCP explanation and 48.5% evaluated the explanation favorably. Evaluations by parents with limited health literacy were less favorable.
It is feasible to follow parents for psychosocial outcomes after NBS. Preliminary data about communication is mixed, but further data will soon describe psychosocial outcomes, and investigate outcomes’ associations with communication.
Newborn Screening; Genetic counseling; Genetic screening; Cystic fibrosis; Sickle cell trait; Provider-patient communication; Communication quality assurance
Newborn screening (NBS) for CF has become widespread, although there are multiple strategies. Little is known about outcomes such as age of diagnosis after different NBS methods.
We used the U.S. Cystic Fibrosis Foundation Patient Registry to identify infants with CF born between 2001 and 2008 in states that utilized NBS. We compared ages at diagnosis, genotyping, sweat test, and first visit to a CF Centre between states that used serial immunoreactive trypsinogen (IRT/IRT) levels and states that used IRT and DNA analysis (IRT/DNA).
We identified 1,288 infants with CF. Compared to infants born in IRT/IRT states, infants born in IRT/DNA states were younger at the time of diagnosis (median 2.3 weeks versus 4.0 weeks in IRT/IRT states, p<0.001), genotyping (0.7 weeks versus 5.3 weeks, p<0.001), and initial CF Centre visit (5.9 weeks versus 7.7 weeks, p=0.008).
Although there is room to improve outcomes with both strategies, infants born in IRT/DNA states have treatment initiated at a younger age than infants born in IRT/IRT states.
To assess whether reporting “possible cystic fibrosis (CF)” newborn screening (NBS) results via fax plus simultaneous telephone contact with primary care providers (PCPs), versus fax alone, influenced three outcomes: getting a sweat chloride test, age at sweat chloride test, and sweat-testing before 8 weeks old.
Retrospective cohort comparison of infants born in Wisconsin whose PCPs received telephone intervention (n=301), versus recent historical controls whose PCP did not (n=355). Intervention data were collected during a longitudinal research and quality improvement effort; de-identified comparison data were constructed from auxiliary NBS tracking information. Parametric and nonparametric statistical analyses tested for group differences.
Most infants (92%) with “possible CF” NBS results whose PCPs lacked telephone intervention ultimately underwent sweat-testing, underlining efficacy for fax-only reporting. Telephone intervention was significantly associated with improvements in infants undergoing sweat-testing at both ≤6 and <8 weeks and a slight, but non-significant, 3.5-day reduction in infants’ age at sweat-testing. The effect of telephone intervention was greater for PCPs whose patients underwent sweat-testing at community-affiliated medical centers versus academic medical centers (p=0.008).
Reporting “possible CF” NBS results via fax plus simultaneous telephone follow-up with PCPs increases the number of infants who have sweat chloride tests before 8 weeks of age, when affected infants are more likely to receive full benefits of early diagnosis and treatment.
Neonatal screening; sweat chloride testing; heterozygote; genetic carrier detection; genetic testing; public health genetics; parent-provider communication
Rationale: Most children with cystic fibrosis (CF) experience a slow decline in spirometry, although some children continue to be at risk for more significant lung disease progression. Chest computed tomography (CT) scans have been shown to be more sensitive to changes in lung disease than spirometry and may provide a means for predicting future lung disease progression.
Objectives: We hypothesized that Brody chest CT scan scores obtained in 2000 in a prospectively monitored cohort of children with CF would be associated with the most recent measures of lung disease severity.
Methods: Brody chest CT scan scores were calculated for 81 children enrolled in the Wisconsin CF Neonatal Screening Project. Multivariable linear regression was used to determine associations between Brody scores and the most recent (age 21 yr or June 30, 2010, whichever was later) measures of CF lung disease.
Measurements and Main Results: The mean observation time after the chest CT scan was 7.5 years. Brody chest CT scan scores were significantly associated with the most recent measures of spirometry (P < 0.001) and Wisconsin and Brasfield chest radiograph scores (P < 0.001). The strength of this association was much stronger than spirometry obtained near the time of the chest CT scan (P < 0.01) but not chest radiograph scores.
Conclusions: Chest CT scan scores are associated with future lung disease severity, and quantitative chest imaging (chest CT scan and chest radiograph scores) is more strongly associated with future lung disease severity than measures of spirometry. These findings may help clinicians identify patients at risk of future lung disease progression.
chest x-ray; pulmonary function tests; FEV1; quantitative chest radiography
This cross-sectional mixed method study was a long-term follow-up evaluation of families who participated in an earlier survey of their understanding of cystic fibrosis (CF) genetics and their infants’ false-positive CF newborn screening (NBS) results. Thirty-seven of the original 138 parents participated in the follow-up telephone survey. Results showed parents who received genetic counseling at the time of their infants’ diagnostic sweat tests had significantly higher long-term retention of genetic knowledge than those without genetic counseling. However, both groups still had misconceptions and lacked accurate information about the actual risk associated with being a CF carrier. Most parents either had already informed (65%) or planned to inform (19%) their children about the child’s carrier status. Mean child age at the time of disclosure was 9.2 years. Situational prompts were the most common reasons for informing their children. Neither parental knowledge, medical literacy, nor parental education predicted whether parents informed their children about their carrier status. False-positive NBS results for CF were not associated with parental perceptions of child vulnerability 11–14 years after the testing. Although the sample from this study was small, these findings underscore the benefits of genetic counseling at the time of the diagnostic sweat test and offer information that can assist parents in talking with their children about the implications of having one CFTR mutation.
cystic fibrosis; false-positive; genetic counseling; newborn screening; psychosocial
Over the last 20 years since the discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, more than 1,600 different putatively pathological CFTR mutations have been identified. Until now, however, copy number mutations (CNMs) involving the CFTR gene have not been methodically analyzed, resulting almost certainly in the underascertainment of CFTR gene duplications compared with deletions. Here, high-resolution array comparative genomic hybridization (averaging one interrogating probe every 95 bp) was used to analyze the entire length of the CFTR gene (189 kb) in 233 cystic fibrosis chromosomes lacking conventional mutations. We succeeded in identifying five duplication CNMs that would otherwise have been refractory to analysis. Based upon findings from this and other studies, we propose that deletion and duplication CNMs in the human autosomal genome are likely to be generated in the proportion of approximately 2–3:1. We further postulate that intragenic gene duplication CNMs in other disease loci may have been routinely underascertained. Finally, our analysis of ±20 bp flanking each of the 40 CFTR breakpoints characterized at the DNA sequence level provide support for the emerging concept that non-B DNA conformations in combination with specific sequence motifs predispose to both recurring and nonrecurring genomic rearrangements.
CFTR; copy number mutation; CNM; copy number variation; CNV; deletion; duplication; CGH
Identification of new immunogenic antigens that diagnose initial Pseudomonas aeruginosa infections in patients with cystic fibrosis (CF) alone or as an adjunct to microbiology is needed. In the present study, a proteomic analysis was performed to obtain a global assessment of the host immune response during the initial P. aeruginosa infection of patients with CF. Matrix-assisted laser desorption ionization-time of flight mass spectrometry was used to identify outer membrane protein L (OprL), a non-type III secretion system (TTSS) protein, as an early immunogenic protein during the initial P. aeruginosa infection of patients with CF. Longitudinal Western blot analysis of sera from 12 of 14 patients with CF detected antibodies to OprL during the initial P. aeruginosa infection. In addition, also detected were antibodies to ExoS, ExoU, or ExoS and ExoU, the latter indicating sequential P. aeruginosa infections during initial infections. Detection of serum reactivity to OprL, along with proteins of the TTSS, and in conjunction with microbiology may diagnose initial P. aeruginosa infections in patients with CF.
We recently reported that 60% of newly diagnosed CF children who had pancreatic insufficiency (PI) responded to treatment initiation and achieved catch-up weight gain to a level comparable to their birth weight Z-score within 2 years of diagnosis (“responders”), while the remaining 40% failed to do so (“non-responders”). The present study examined the impact of this early weight recovery on subsequent growth pattern and pulmonary status at age 6 years.
Patients and Methods
Sixty-three children with CF who had PI but no meconium ileus, and were enrolled in the Wisconsin CF Neonatal Screening Project, were studied. “Responders” were defined by a recovery of weight Z-score comparable to that at birth within 2 years of diagnosis. During ages 2–6, growth was evaluated with the combination of height and body mass index. Pulmonary status was evaluated by symptoms, spirometry, quantitative chest radiography and respiratory microbiology.
The majority (71%) of the responders maintained their early weight recovery through age 6 years while only 32% of the non-responders achieved substantial growth improvement during age 2 to 6 years. Proportionately fewer responders reported cough symptoms (10% daytime cough, p =0.02; 22% nighttime cough, p=0.05) compared to non-responders (41% daytime cough, 45% nighttime cough) at age 6. Percent predicted FEV1 (%FEV1) at age 6 was 11% higher in responders (99.5 ± 13.9%) compared to non-responders (88.3 ± 18.5%), p = 0.015. Responders had significantly better Brasfield (20.1 ± 1.4, p = 0.01) and Wisconsin chest radiographic scores (8.3 ± 3.3, p = 0.04) compared to non-responders (Brasfield 18.9 ± 1.8, Wisconsin 12.3 ± 8.3). Respiratory microbiology was not significantly different. Multiple regression analyses indicated that the positive association between responder and %FEV1 at age 6 years remained statistically significant after controlling for infections with Pseudomonas aeruginosa and Staphlococcus aureus and chest radiographic scores. Growth patterns during 2–6 years of age were not associated with pulmonary measures at age 6.
CF patients with PI who achieved early growth recovery within 2 years of diagnosis had fewer cough symptoms, higher lung function and better chest radiography scores at 6 years of age.
Cystic Fibrosis; Growth; Malnutrition; Height; Weight; Body mass index; Pulmonary function; Chest radiograph; Newborn screening
Newborn screening (NBS) for cystic fibrosis (CF) is increasingly being implemented and is soon likely to be in use throughout the United States, because early detection permits access to specialized medical care and improves outcomes. The diagnosis of CF is not always straightforward, however. The sweat chloride test remains the gold standard for CF diagnosis but does not always give a clear answer. Genotype analysis also does not always provide clarity; more than 1500 mutations have been identified in the CF transmembrane conductance regulator (CFTR) gene, not all of which result in CF. Harmful mutations in the gene can present as a spectrum of pathology ranging from sinusitis in adulthood to severe lung, pancreatic, or liver disease in infancy. Thus, CF identified postnatally must remain a clinical diagnosis. To provide guidance for the diagnosis of both infants with positive NBS results and older patients presenting with an indistinct clinical picture, the Cystic Fibrosis Foundation convened a meeting of experts in the field of CF diagnosis. Their recommendations, presented herein, involve a combination of clinical presentation, laboratory testing, and genetics to confirm a diagnosis of CF.
Because it is clearly in the best interests of children with cystic fibrosis to be diagnosed early at <2 months, which can only be achieved routinely by newborn screening, it can be argued that this should be a human right. However, if more harm than good is likely, or if regional “readiness” does not exist, newborn screening should be deferred.
Cystic fibrosis; newborn screening; rights; ethics
All states require some kind of testing for newborns, but the policies are far from standardized. In some states, newborn screening may include genetic tests for a wide range of targets, but the costs and complexities of the newer genetic tests inhibit expansion of newborn screening. We describe the development and technical evaluation of a multiplex platform that may foster increased newborn genetic screening.
MultiCode® PLx involves three major steps: PCR, target-specific extension, and liquid chip decoding. Each step is performed in the same reaction vessel, and the test is completed in ~3 h. For site-specific labeling and room-temperature decoding, we use an additional base pair constructed from isoguanosine and isocytidine. We used the method to test for mutations within the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The developed test was performed manually and by automated liquid handling. Initially, 225 samples with a range of genotypes were tested retrospectively with the method. A prospective study used samples from >400 newborns.
In the retrospective study, 99.1% of samples were correctly genotyped with no incorrect calls made. In the perspective study, 95% of the samples were correctly genotyped for all targets, and there were no incorrect calls.
The unique genetic multiplexing platform was successfully able to test for 31 targets within the CFTR gene and provides accurate genotype assignments in a clinical setting.
The role of vitamin E in human nutrition was studied by investigation of patients with cystic fibrosis (CF) and associated pancreatic insufficiency. Vitamin E status was assessed by measurement of the plasma concentration of the principal circulating isomer, α-tocopherol. Results of such determinations in 52 CF patients with pancreatogenic steatorrhea revealed that all were deficient in the vitamin. The extent of decreased plasma tocopherol varied markedly but correlated with indices of intestinal malabsorption, such as the serum carotene concentration and percentage of dietary fat absorbed. Supplementation with 5-10 times the recommended daily allowance of vitamin E in a water-miscible form increased the plasma α-tocopherol concentrations to normal in all 19 CF patients so evaluated.
Studies on the effects of vitamin E deficiency focused on possible hematologic alterations. An improved technique was developed to measure erythrocyte hemolysis in vitro in the presence of hydrogen peroxide. While erythrocyte suspensions from control subjects demonstrated resistance to hemolysis during a 3-h incubation, all samples from tocopherol-deficient CF patients showed abnormal oxidant susceptibility, evidenced by greater than 5% hemoglobin release. The degree of peroxide-induced hemolysis was related to the plasma α-tocopherol concentration in an inverse, sigmoidal manner. The possibility of in vivo hemolysis was assessed by measuring the survival of 51Cr-labeled erythrocytes in 19 vitamin-E deficient patients. A moderate but statistically significant decrease in the mean 51Cr erythrocyte half-life value was found in this group. Measurement of erythrocyte survival before and after supplementation of 6 patients with vitamin E demonstrated that the shortened erythrocyte lifespan could be corrected to normal with this treatment. Other hematologic indices in deficient subjects, however, were normal and did not change upon supplementation with vitamin E.
It is concluded that CF is invariably associated with vitamin E deficiency, provided that the patient in question has pancreatic achylia and is not taking supplementary doses of tocopherol. Concomitant hematologic effects consistent with mild hemolysis, but not anemia, occur and may be reversed with vitamin E therapy. Patients with CF should be given daily doses of a water-miscible form of vitamin E to correct the deficiency.