Epidemiology of cystic fibrosis-related diabetes

OBJECTIVES: Cystic fibrosis-related diabetes (CFRD) has emerged as an important complication of CF. To better understand who is at risk of developing CFRD, to gain insight into the impact of CFRD on pulmonary and nutritional status, and to assess the association of CFRD with various practice patterns and comorbid conditions, we characterized the Epidemiologic Study of Cystic Fibrosis (ESCF) patient population. STUDY DESIGN: Analyses were performed on the 8247 adolescents and adults who were evaluated at one of 204 participating sites during 1998. CFRD was defined as the use of insulin or an oral hypoglycemic agent at any time during the year. RESULTS: Previously reported risk factors for CFRD including age, gender (female), and pancreatic insufficiency were confirmed in this study. Patients with CFRD had more severe pulmonary disease, more frequent pulmonary exacerbations, and poorer nutritional status as compared with those without diabetes. CFRD also was associated with liver disease. CONCLUSIONS: CFRD is a common complication in adolescents and adults that is associated with more severe disease.     

Cystic fibrosis birth rates in Canada: a decreasing trend since the onset of genetic testing

OBJECTIVE: To estimate cystic fibrosis (CF) birth rates in Canada from 1971 to 2000 and to assess the population impact of genetic testing in families with a history of CF, after identification of the CF transmembrane conductance regulator gene in 1989. STUDY DESIGN: Age-at-diagnosis data were obtained from the Canadian Cystic Fibrosis Foundation Patient Data Registry and Canadian births for the corresponding years from Canadian Vital Statistics. Estimates of the CF birth rate in each year were based on a nonparametric model that allows the birth rate to vary across the years and adjusts for censoring of currently undiagnosed patients. RESULTS: The overall CF birth rate from 1971-1987 was 1/2714 with no increasing or decreasing trend. Beginning in 1988, 1 year before identification of the CF transmembrane conductance regulator gene, estimated CF birth rates followed a linear decline to an estimated rate of 1/3608 in 2000. CF birth rates may have stabilized in the last few years, but further decline may occur with implementation of carrier screening in the general population. CONCLUSIONS: These results demonstrate the temporal association of genetic testing and declining CF birth rates in Canada. They may assist in decisions relating to the allocation of resources for prenatal and neonatal CF screening programs.     

Quality-of-life in children and adolescents with cystic fibrosis managed in both regional outreach and cystic fibrosis center settings in Queensland

OBJECTIVES: To assess the health-related quality-of-life (HRQOL) of children/adolescents with cystic fibrosis (CF) and compare HRQOL in children managed by cystic fibrosis outreach service (CFOS) with those treated in a cystic fibrosis center (CFC). To compare HRQOL of children with CF in Queensland with previously published HRQOL data from the United States and examine the relationship between HRQOL scores and pulmonary function. STUDY DESIGN: Participants were children/adolescents with CF and their parents managed by the Royal Children's Hospital Queensland at a CFC or CFOS. Two HRQOL surveys were used: PedsQL and Cystic Fibrosis Questionnaire (CFQ). RESULTS: There were 91 CFC and 71 CFOS participants with similar demographics. PedsQL total summary score was statistically higher in CFOS, P=.05. There was no significant difference in CFQ scores between groups. Queensland parents reported lower HRQOL for their children compared with US parents (P<.01) despite similar pulmonary function. Declining pulmonary function correlated with worse CFQ scores in adolescents, P<.05. CONCLUSIONS: Children living in regional Queensland reported as good as or slightly better HRQOL compared with children attending a CFC. Parent proxy HRQOL scores were generally low suggesting a reduced perception of HRQOL by parents for their children.     

Frequency of Genotype With ΔF508 Mutation in CFTR Gene Among Iranian Cystic Fibrosis Patients With Pancreatic Insufficiency

Background:

Cystic fibrosis (CF) is the most prevalent lethal autosomal recessive disease with a broad spectrum of phenotypes. Mutation of ΔF508 in the CFTR gene is the most important and lethal mutation in CF, which contains 70% of all predisposing mutations for CF worldwide.

Objectives:

Determining frequency of genotypes with ΔF508 mutation in CFTR gene, and evaluation of correlation between genotype and phenotype of Iranian patients with CF.

Patients and Methods:

Thirty six patients were included in this cross sectional study. ΔF508 mutations in both alleles of the CFTR gene were checked.

Results:

Among 36 pediatric patients, ΔF508 mutation was detected in 9 (25%) patients; 2 patients were heterozygous, and 7 patients homozygous for this mutation. From overall 72 tracked alleles, 11 (15.2%) were found to have ΔF508 mutations. Differences in prevalence of dyspnea and bronchiectasis were significant in homozygote group, compared with non-mutated group for ΔF508.

Conclusions:

It seems that more ΔF508 mutated alleles lead to more severe symptoms of CF.     

Clinical and Genetic Features in Patients with Cystic Fibrosis in Southwestern Iran

Objective

Cystic fibrosis (CF) is a common autosomal recessive genetic disease caused by a mutation in the CF transmembrane conductance regulatory (CFTR) gene. This study attempted to identify the most common CFTR mutations and any correlations between certain mutations and the clinical presentation of the disease in CF patients in southwestern Iran.

Methods

Twenty nine common CFTR gene mutations were examined in 45 CF patients.

Findings

Chronic cough, intestinal obstruction, dehydration, heat exhaustion and steatorrhea were the most common early clinical symptoms among our patients. The most common mutation was ΔF508, with an allele frequency of 21%. The homozygous ΔF508 mutation was observed in eight patients (18%), and three patients (7%) were ΔF508 carriers. The 2183AA > G mutation was observed in four patients, one of whom was also a ΔF508 carrier. The R1162X mutation was detected in two patients. The G542X, R334W and N1303K mutations were detected each in one patient, the first of whom was also a ΔF508 carrier.

Conclusion

Out of 45 patients, 27 (60%) had none of the CFTR gene mutations we tested for. The most frequent mutations in southwestern Iranian patients with CF should be identified by sequencing the entire CFTR gene in order to optimize the design of a diagnostic kit for common regional mutations.     

Association of TNF-α Gene Variants With Clinical Manifestation of Cystic Fibrosis Patients of Iranian Azeri Turkish Ethnicity

Background:

Cystic fibrosis (CF), a life-limiting autosomal recessive disorder, is considered a monogenic disease that is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. According to several studies, mutation analysis of the cystic fibrosis transmembrane conductance regulator (CFTR) gene alone is insufficient to predict the phenotypic manifestations observed in cystic fibrosis (CF) patients. In addition, some patients with a milder CF phenotype do not carry any pathogenic mutation. Tumor Necrosis Factor-alpha (TNF-α) contributes to the pathophysiology of CF by causing cachexia. There is a reverse association between TNF-α concentration in patient''s sputum and their pulmonary function.

Objectives:

To assess the effect of non-CFTR genes on the clinical phenotype of CF, two polymorphic sites (-1031T/C and -308G/A) of the TNF-α gene, as a modifier, were studied.

Patients and Methods:

Focusing on the lung and gastrointestinal involvement as well as the poor growth, we first investigated the role of TNF-α gene in the clinical manifestation of CF. Furthermore, based on the hypothesis that the cumulative effect of specific alleles of multiple CF modifier genes, such as TNF-α, may create the final phenotype, we also investigated the potential role of TNF-α in non-classic CF patients without a known pathogenic mutation. In all, 80 CF patients and 157 healthy control subjects of Azeri Turkish ethnicity were studied by the PCR–RFLP method. The chi-square test with Yates'' correction and Fisher''s exact test were used for statistical analysis.

Results:

The allele and genotype distribution of the investigated polymorphisms, and their associated haplotypes were similar in all groups.

Conclusions:

There was no evidence that supported the association of TNF-α gene polymorphisms with non-classic CF disease or the clinical presentation of classic CF.     

Impact of inhaled corticosteroids on the risk of early Pseudomonas aeruginosa acquisition in cystic fibrosis

Aim: To investigate the role of inhaled corticosteroids (IC) on the risk of Pseudomonas aeruginosa acquisition before the age of 10 y in cystic fibrosis (CF) patients. Methods: For each subject the cumulative dose kg^-1 of IC received for each year of age was calculated until the end of follow-up. The age at CF diagnosis, the nutritional status (NS) and the number of respiratory exacerbations (RE) were used as surrogate measures for the severity of CF. Results: A total of 83 patients (40 M, 43 F) entered the study. Their median length of follow-up was 4.4 y, for a total of 386 person-years at risk. Twenty-three patients acquired P. aeruginosa at a median age of 4.6 y (range 0.4-9.9 y). The estimated survival without P. aeruginosa acquisition was 65% at 10 y of age. The effect of different risk factors (IC, NS, RE and age at CF diagnosis) on the probability of P. aeruginosa acquisition was evaluated: none of them was significantly associated with the risk of P. aeruginosa acquisition. In particular, patients receiving very high cumulative doses of IC (4th quartile) had a non-significantly increased risk of P. aeruginosa acquisition compared with those receiving low doses of IC (1st quartile) (hazard ratio = 1.73, 95% confidence limits 0.40-7.38).

Conclusion: This retrospective study was not able to demonstrate any role of IC in increasing the risk of P. aeruginosa acquisition. This complication seems to occur at a constant pace that is independent of CF severity and age. Prospective multi-institutional randomized studies are needed to investigate the effects of high-dose IC in CF patients.     

Continuous glucose monitoring in adolescents with cystic fibrosis

The presence of cystic fibrosis (CF)-related diabetes was evaluated in 19 adolescents with CF by continuous glucose monitoring system (CGMS) and oral glucose tolerance testing. CGMS confirmed diabetic glucose excursions in 7/19 subjects deemed diabetic on oral glucose tolerance testing. CGMS is a useful tool for detecting hyperglycemia in CF.     

Failure of conventional strategies to improve nutritional status in malnourished adolescents and adults with cystic fibrosis

The use of oral dietary supplements was compared with dietary counseling in 13 malnourished patients (3 males, mean age 18.1 years) with cystic fibrosis. Energy intake and nutritional status were evaluated over 3 months. There was no significant change in energy intake or percent ideal body weight in either group.     

Novel de novo large deletion in cystic fibrosis transmembrane conductance regulator gene results in a severe cystic fibrosis phenotype

We identified c.1521_1523delCTT and c.1679+94_2619+986del8118 in trans in a 6-year-old boy with a severe cystic fibrosis phenotype. The first deletion was inherited maternally, but the latter had arisen de novo.