Personal experiences of cystic fibrosis (CF) carrier couples prospectively identified in CF families

This qualitative study explores the experiences of cystic fibrosis (CF) carrier couples, prospectively identified in CF families, and the impact of the resulting genetic risk on reproductive behavior. Of the 12 couples identified until 1997, seven couples participated in semistructured interviews and two couples filled in a questionnaire, two to eight years after receipt of the test-results. After receiving the results, most couples reported that they were shocked, because they did not expect to both be carriers. More anxiety was expressed by those who were pregnant (n = 4) at the time of testing. There were reported difficulties in disclosing the results to family members, and the reactions of family members were not always supportive. After testing, some couples had problems with reproductive decision-making. All viable pregnancies (17 in 8 couples) were monitored by prenatal diagnosis; all affected pregnancies were terminated (6 in 4 couples). Couples who have live-born children after testing may subsequently have concerns during infancy about the correctness of the results of prenatal diagnosis and how to inform their children. Most couples did not regret the testing and, in general, the counseling was experienced positively, although some dissatisfaction was reported with regard to the psychological support received during pregnancy. Couples supported the idea of carrier screening in the general population, although various concerns were expressed. The results indicate a preference for testing before pregnancy. These findings may be useful in investigating possible dilemmas caused by the introduction of population carrier screening. Observations reported here might also apply to other recessively inherited disorders.     

Nine mutations in the cystic fibrosis (CF) gene account for 80% of the CF chromosomes in French patients

Thirteen mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene have been screened in a French sample of 185 cystic fibrosis (CF) patients, together with their respective associated RFLP haplotypes at the linked D7S23 locus (XV2C and KM19 markers). The respective frequencies of the mutations showed that 9 of them account for 80% of the CF chromosomes. Implications for prenatal diagnosis and heterozygote detection are defined and discussed. The well-known great excess of RFLP B marker within CF chromosomes is partially explained by two already characterized mutations highly associated with haplotype B: delta F508 and G542X. Similarly, the excess of haplotype D within CF chromosomes is partially explained by the association between delta I507 and this haplotype. These results may suggest the existence of two still untested or uncharacterized mutations, whose frequencies could be near 1%, one which would be associated with haplotype B and a second which would be associated with haplotype D. The possible cause of the specific association between most of the main different CF mutations and the RFLP haplotype B is discussed.     

Proband and parent assistance in identifying relatives for cystic fibrosis carrier testing

To identify, contact, and offer free cystic fibrosis (CF) carrier education, testing, and genetic counseling to the first, second, and third degree relatives of individuals with CF, study personnel contacted probands or the parents of minor probands requesting assistance in identifying relatives. We requested family pedigrees, including names, addresses, and phone numbers and if necessary a saliva sample for determination of the specific CF mutations in the family. Two hundred three families of 220 probands being followed at a large CF clinic in the Southeastern United States were eligible for inclusion in the study. Of the 203 families 109 (53.7%) assisted by providing contact information on relatives and, when necessary, a saliva sample for mutation analysis. An additional 33 (16.4%) agreed to assist but did not provide either or both contact information or saliva samples. Sixty-one (30.1%) declined to provide assistance. Thirteen percent of the probands/parents wanted to talk with relatives before providing contact information. A logistic regression model predicting proband/parent assistance is provided. This study suggests that the active outreach method used here to identify at risk relatives to offer them CF carrier testing resulted in somewhat lower proband or parent assistance than reported by other similar approaches. The strengths and weaknesses of this approach, including comments by probands and parents on the method, are discussed. © 1996 Wiley-Liss, Inc.     

Screening for CF mutations in adult cystic fibrosis patients with a directed and optimized SSCP strategy

Twenty adolescent and adult cystic fibrosis (CF) patients have been studied for the presence of mutations in the CFTR gene. Mutations other than deltaFSOS have been detected by comparison to the single-stranded conformation polymorphism (SSCP) pattern of known mutations in eight exons, in which 80% of the more common mutations are present. Each mutation was confirmed by direct sequencing. For each of the analyzed exons, optimal SSCP conditions have been determined that allow all available known mutations in that exon to be distinguished from each other. This approach allowed mutations to be defined in 75% of the non deltaF508 alleles and 92% of all CF alleles in this cohort. © 1994 Wiley-Liss, Inc.     

Highest heterogeneity for cystic fibrosis: 36 mutations account for 75% of all CF chromosomes in Turkish patients

We analyzed the CFTR locus in 83 Turkish cystic fibrosis patients to identify mutations, haplotypes, and the carrier frequency in the population. We detected 36 different mutations in 125 (75%) of the total 166 CF chromosomes. Seven novel mutations were identified: four missense (K68E, Q493P, E608G, and V1147I), two splice-site (406 -3T > C and 3849 +5G > A), and one deletion (CFTRdele17b,18). The data showed that the Turkish population has the highest genetic heterogeneity at the CFTR locus reported so far. The results of this thorough molecular analysis at the CFTR locus of a population not of European descent shows that CF is not uncommon in all such populations. The large number of mutations present, as well as the high heterogeneity in haplotypes associated with the mutations suggests that most of the mutations have persisted for a long time in the population. Consistently, the carrier frequency is assessed to be high, indicating that the disease in the population is ancient.     

Molecular characterization of Burkholderia cepacia isolates from cystic fibrosis (CF) patients in an Italian CF center

Bacteria of the Burkholderia cepacia complex consist of a number of closely related genomic species (genomovars) potentially pathogenic for cystic fibrosis (CF) patients, collectively referred to as the B. cepacia complex. The genomovar status and epidemiological relatedness of B. cepacia complex strains recovered from CF patients, attending a CF Center at the University Hospital "Policlinico Umberto I" of Rome, were investigated using 16S rRNA PCR-RFLP, recA PCR-RFLP, genomovar-specific PCR, and RAPD. Forty-seven isolates identified as B. cepacia by commercial systems were repeatedly recovered from 19 CF patients. The taxonomy approach used in this study showed that 17 of the 19 patients were colonized by B. cepacia complex strains. Genomovar III (11 strains) was the most prevalent genomovar. Two strains of genomovar I, one B. stabilis (genomovar IV), one B. multivorans (genomovar II), and 4 strains of B. anthina (genomovar VIII) were also identified. This is the first report of multiple patient colonization by B. anthina in a CF center. The epidemiological and genetic relatedness as well as the presence of molecular markers associated with virulence and transmissibility of the B. cepacia complex strains were determined and probable patient-to-patient spread was observed.     

Analyzing DNA from buccal cells is a reliable method for the exclusion of cystic fibrosis. Results of a pilot study.

PURPOSE: In children there is frequently a reason to exclude cystic fibrosis. Sweat testing is used for this. Because sweat testing has some disadvantages we investigated whether analyzing DNA for the local most common CFTR mutations, harvested from buccal cells, is reliable as a method to exclude cystic fibrosis. METHODS: In patients in whom a sweat test had been ordered during the period January 1, 2002 to December 31, 2004, we harvested buccal cell DNA for analysis. When blood was available, DNA from leukocytes was also analyzed. RESULTS: A total of 73 sweat tests were ordered during the two-year study period, mostly because of recurrent pulmonary infections (36; 49%), failure to thrive (20; 27%) and chronic diarrhea (10, 14%). In 70, children the results of the sweat test were normal, in three patients the results were borderline. Sixty buccal smears were analyzed and no patient was homozygous for cystic fibrosis, two were heterozygous for cystic fibrosis. In none of the children the diagnosis of cystic fibrosis was established. CONCLUSION: Analyzing DNA in cells, harvested from the buccal cells, is a reliable alternative to exclude cystic fibrosis. It is safe, simple, and child-friendly.     

Absence of mutations in the interspecies conserved regions of the CFTR promoter region in cystic fibrosis (CF) and CF related patients.

This study was aimed at testing if a 5.2 kb untranslated region on both sides of the first CFTR exon, shown to contain regulatory elements, could carry mutations responsible for cystic fibrosis (CF) or CF related phenotypes. Selection of the DNA segments studied within this region was based upon the identification of conserved sequences throughout evolution (phylogenetic footprints, PFs). Comparison of the CFTR sequences in eight species representing four orders of mammals (man, gibbon, rhesus monkey, squirrel, monkey, rabbit, cow, rat, and mouse) identified four clusters of PFs within the 3.9 kb of DNA sequence upstream from the initiation codon, as well as two nearby PFs at +1 kb within intron 1. Six DNA segments containing PFs were scanned for mutations by denaturing gradient gel electrophoresis (DGGE) in patients with CF (n = 29), congenital bilateral absence of the vas deferens (n = 143), or disseminated bronchiectasis (n = 33), for whom only one or no mutations had been identified despite extensive DGGE analysis of the 27 CFTR exons and exon/intron boundaries. Only one polymorphism (-966 T-->G) was identified with a frequency of 2.2% and no other sequence variations were found. This study reinforces the idea that the promoter region in the CFTR is not frequently mutated.     

Development and evaluation of a multi-family psychoeducational program for cystic fibrosis

The development, implementation and evaluation of a psychoeducational program for families with a child affected by cystic fibrosis (CF) is described. Aim of the program was to strengthen the families' coping with CF-related problems and to improve adherence with chest physiotherapy.Sixteen families from an outpatient CF-clinic participated. Parents and children were educated both individually as well as together in multi-family groups. Teaching, practicing and group discussions were balanced in each session. In a pre-post-design the following variables were evaluated: parental coping, parental health beliefs, children's coping, adherence, and knowledge about CF.The parental coping patterns and health beliefs remained unchanged in the study group. Children developed more search for social support, whereas their competence and optimism decreased and withdrawal increased slightly as perceived by the parents. There is a subgroup with poor family functioning and adherence at pretest which improves after the intervention.Family-centered psychoeducational intervention may be a promising supportive strategy for children with CF, especially if it is dedicated to families with poor adaptation to the disease.     

Fast development of CE IVD molecular diagnostic kits: Highly specific microarray kit for 49 cystic fibrosis mutations

We present here an example of fast molecular diagnostic test development using HairLoop™ probes. This test is a microarray-based diagnostic kit, will be CE IVD labeled in 2008, and was developed for the diagnostic of 49 point mutations of the cystic fibrosis disease. Highly specific HairLoop™ probes allowed the development of this very simple-to-use kit, in less than one year.     

A 31-mutation assay for cystic fibrosis testing in the clinical molecular diagnostics laboratory

We devised a set of allele-specific probes to detect simultaneously 31 known cystic fibrosis mutations using PCR and the reverse dot blot detection format. The assay has been implemented in a clinical setting to the screening of over 750 individuals. Of these 102 Caucasians, 20 Hispanics and 1 Indian patient were affected with cystic fibrosis. The mutation detection rate in the 204 Caucasian and 40 Hispanic CF chromosomes was respectively, 88% and 85%. The availability of the probe sequences to CF screening laboratories should allow implementation of this assay in a clinical setting and comparison of its mutation typing rate among different centers. © 1995 Wiley-Liss, Inc.     

Anti-GAD65 reactive peripheral blood mononuclear cells in the pathogenesis of cystic fibrosis related diabetes mellitus

OBJECTIVE: A role of autoreactive T cells for type 1 diabetes pathogenesis is considered crucial. In our pilot study we addressed if autoreactive mononuclear cells are present also in peripheral blood of patients with other specific forms of diabetes as cystic fibrosis related diabetes (CFRD). METHODS: Cellular immune responses to a known beta-cell autoantigen (GAD65 and GAD65 derived peptides) were analysed by ELISPOT (IFN-gamma) and by protein microarray analysis in four patients suffering from CFRD, in four cystic fibrosis (CF) patients without diabetes, in eight type 1 diabetes patients (without CF) and in four healthy controls. RESULTS: Response to the autoantigen GAD65 (protein and peptides) was observed in 7/8 patients suffering from CF and in all type 1 diabetes patients. Post-stimulation production of Th1 cytokines (IFN-gamma, TNF-beta) was observed in 2/4 CFRD, 1/4 CF patients and in 7/8 type 1 diabetes patients. All these patients carry prodiabetogenic HLA-DQ genotype. Th2- and Th3 type of cytokine pattern was observed in 2/4 CF patients. Production of IL-8 was observed in the third CFRD as well as in the third CF patient and in 1/8 type 1 diabetes patient and borderline production of this chemokine was also observed in 2/4 healthy controls. No reaction was observed in the other 2/4 healthy controls and in the fourth CFRD patient who carried a strongly protective genotype and did not produce autoantibodies. The most potent peptide of GAD65 was amino acids 509-528. CONCLUSIONS: We consider our observations as a sign of a reaction directed against the self-antigen GAD65 that are closely connected to type 1 diabetes. In CF patients who do not develop diabetes autoreactive mechanisms are very probably efficiently suppressed by immune self-tolerance mechanisms. CFRD patients are a heterogenic group. To disclose those who may display features of autoimmune diabetes could have an impact for their therapy and prognosis.     

Carrier screening for cystic fibrosis in US genetic testing laboratories: a survey of laboratory directors

Initial guidelines for cystic fibrosis (CF) carrier screening were issued in 2001 by the American College of Medical Genetics and the American College of Obstetricians and Gynecologists and updated in 2004. It is unknown how these guidelines have influenced laboratory practice. This study examined the uptake of two components of these guidelines for CF screening in genetic testing laboratories. A survey of directors of US genetic testing laboratories was conducted. Of 190 respondents, 178 answered questions about CF testing. Nearly half (49%) performed some type of DNA testing for CF; most of these (92%) performed CF carrier screening. Ten percent used a 23-mutation panel for CF screening. The results of 5T tests were reported as a reflex test by 79% of laboratories, while 8% always returned 5T results and 7% never returned them. Seven percent of laboratories adopted both guidelines, 80% adopted one of the two guidelines, and 13% had not adopted either recommendation, suggesting that factors other than clinical guidelines may influence laboratories' CF screening practices. Further studies are needed to determine whether the adoption of CF screening guidelines has significant clinical or economic effects on population-based CF screening programs.     

Anti-GAD65 reactive peripheral blood mononuclear cells in the pathogenesis of cystic fibrosis related diabetes mellitus

Objective: A role of autoreactive T cells for type 1 diabetes pathogenesis is considered crucial. In our pilot study we addressed if autoreactive mononuclear cells are present also in peripheral blood of patients with other specific forms of diabetes as cystic fibrosis related diabetes (CFRD). Methods: Cellular immune responses to a known β-cell autoantigen (GAD65 and GAD65 derived peptides) were analysed by ELISPOT (IFN-γ) and by protein microarray analysis in four patients suffering from CFRD, in four cystic fibrosis (CF) patients without diabetes, in eight type 1 diabetes patients (without CF) and in four healthy controls. Results: Response to the autoantigen GAD65 (protein and peptides) was observed in 7/8 patients suffering from CF and in all type 1 diabetes patients. Post-stimulation production of Th1 cytokines (IFN-γ, TNF-β) was observed in 2/4 CFRD, 1/4 CF patients and in 7/8 type 1 diabetes patients. All these patients carry prodiabetogenic HLA-DQ genotype. Th2- and Th3 type of cytokine pattern was observed in 2/4 CF patients. Production of IL-8 was observed in the third CFRD as well as in the third CF patient and in 1/8 type 1 diabetes patient and borderline production of this chemokine was also observed in 2/4 healthy controls. No reaction was observed in the other 2/4 healthy controls and in the fourth CFRD patient who carried a strongly protective genotype and did not produce autoantibodies. The most potent peptide of GAD65 was amino acids 509–528. Conclusions: We consider our observations as a sign of a reaction directed against the self-antigen GAD65 that are closely connected to type 1 diabetes. In CF patients who do not develop diabetes autoreactive mechanisms are very probably efficiently suppressed by immune self-tolerance mechanisms. CFRD patients are a heterogenic group. To disclose those who may display features of autoimmune diabetes could have an impact for their therapy and prognosis.     

Comparative evaluation of the Iatron serological Candida check kit and the API 20C kit for identification of medically important Candida species.

A newly developed commercial serological test (Iatron Laboratories, Inc., Tokyo, Japan) for the rapid identification of medically important species of Candida was evaluated against the API 20C (Analytab Products, Plainview, N.Y.) and the standard Wickerham assimilation and fermentation procedures. Our results indicated that the Iatron and the API 20C methods are 95% accurate since both permitted identification of 78 of 82 Candida isolates, representing eight medically important species. None of the tests on nine Cryptococcus, six Trichosporon, three Geotrichum, three Saccharomyces, and one Rhodotorula species yielded false-positive reactions. False-positive serological tests occurred with a species of Pichia and Candida rugosa. The API 20C procedure correctly identified C. rugosa but not the Pichia sp. The Iatron method permitted reliable identification of the Candida species in 10 min to 5 h, whereas the API 20C procedure required 48 to 72 h. Neither method could properly identify sucrose-negative Candida tropicalis or Candida lusitaniae isolates. In addition, Candida albicans isolates could be serotyped by the Iatron method.     

Comparison of mannitol salt agar and blood agar plates for identification and susceptibility testing of Staphylococcus aureus in specimens from cystic fibrosis patients

Antimicrobial susceptibilities of Staphylococcus aureus strains can be determined accurately by using isolates from mannitol salt agar, and yellow isolates on mannitol salt agar at quantities of >1+ can be reported as S. aureus. These methods decrease the time to identification/antimicrobial susceptibility testing of S. aureus and decrease costs through eliminating additional testing.     

Superantigens and cystic fibrosis: resistance of presenting cells to dexamethasone

Staphylococcus aureus, a common pulmonary pathogen in cystic fibrosis (CF), produces exotoxins that are extremely potent superantigens. A number of animal studies have shown that superantigens cause pulmonary inflammation, but the possible role of superantigens in CF has not been investigated. The present study assessed possible differences between control and CF B cells in presenting superantigens to T cells. Immortalized B-cell lines were used as superantigen-presenting cells to avoid environmental influences (e.g., infection or antibiotics) common to freshly isolated cells. The results show that CF B-cell lines presented a staphylococcal superantigen to the immortalized T-cell line (Jurkat) as effectively as did control B-cell lines as measured by interleukin-2 production. However, in contrast to the case for control B-cell lines, dexamethasone did not inhibit CF B-cell lines from presenting superantigen. The resistance of superantigen-presenting CF B cells to corticosteroids suggests that the pulmonary response to superantigens may be poorly regulated in CF, leading to an exaggerated inflammatory response to S. aureus.