Donatello Salvatore

An overview of international literature from cystic fibrosis registries: 2. Neonatal screening and nutrition/growth

BACKGROUND This is the second article related to a review of the literature based on data from national cystic fibrosis (CF) registries up to June 2008 and covering a total of 115 studies. It focuses on two topics: neonatal screening (NS) and nutritional status, with particular reference to growth. METHODS Ten papers meeting the inclusion criteria were found on the topic of NS and its impact on the course of the disease, and were analyzed according to a dedicated grid. The issue of nutrition was addressed by 14 studies, analyzed according to similar criteria. RESULTS Most of the studies report benefits of early diagnosis by NS, albeit to variable degrees. The benefits were assessed in terms of better nutritional status and growth, but also in terms of lower overall morbidity rate as compared to subjects diagnosed by symptoms. The main biases of these studies, which partly undermine the validity of their results, are also analyzed. A part of our analysis on nutrition/growth is dedicated to the identification of the most suitable parameters to define malnutrition: in children older than two years the body mass index percentile (BMIp) appears to be the most sensitive and significantly associated with respiratory function. Better nutritional status and satisfactory growth appear to be associated with better lung function and lower risk of death. The relationship between nutritional status and socio-economic status is also of interest. CONCLUSIONS CF registry studies support the outcome of cohort observational studies i.e. that pre-symptomatic early diagnosis is beneficial, especially in terms of nutritional status and growth. Studies on nutrition indicate that good nutritional status is associated with better respiratory function and prognosis. Regarding methods, the need emerged to manage potential biases of this kind of non randomized studies, resorting to suitable statistical techniques, such as matching and stratification and, above all, to multivariate methods able to provide estimates adjusted for the main covariates tested.

An overview of international literature from cystic fibrosis registries: 1. Mortality and survival studies in cystic fibrosis

Patient registries are organized systems of data collection for scientific, clinical or health strategy purposes. Aims of our review were to document scientific literature based on data and information from cystic fibrosis (CF) registries; to understand which clinical problems have been addressed and for which of these the studies concerned have correctly answered the questions raised (i.e. a methodological critique) and to identify clinical issues in need of further investigation. The review included primary studies starting from a formally constituted CF registry of at least national level, using data from the registry to evaluate research hypotheses. This article is an overview of the research undertaken, focusing in detail on the issues of mortality and survival. The studies considered here focused mainly or secondarily on survival in CF, the aim being to ascertain an improving trend, identify any prognostic factors and, in some cases, attempt to provide a predictive model of survival.

Genetic history of cystic fibrosis mutations in italy. I. Regional distribution

Earlier analysis of the Italian population showed patterns of genetic differentiation that were interpreted as being the result of population settlements going back to pre‐Roman times. DNA disease mutations may be a powerful tool in further testing this hypothesis since the analysis of diseased individuals can detect variants too rare to be resolved in normal individuals. We present data on the relative frequencies of 60 cystic fibrosis (CF) mutations in Italy and the geographical distribution of the 12 most frequent CF mutations screened in 3492 CF chromosomes originating in 13 Italian regions. The 12 most frequent mutations characterize about 73% of the Italian CF chromosomes. The most common mutation, ΔF508, has an average frequency of 51%, followed by N1303K and G542X, both with average frequencies around 5%. Multivariate analyses show that the relative frequencies of CF mutations are heterogeneous among Italian regions, and that this heterogeneity is weakly correlated with the geographical pattern of non‐DNA ‘classical’ genetic markers. The northern regions are well differentiated from the central‐southern regions and within the former group the western and eastern regions are remarkably distinct. Moreover, Sardinia shows the presence of mutation T338I, which seems absent in any other European CF chromosome. The north‐western regions of Italy, characterized by the mutation 1717‐1G→A, were under Celtic influence, while the north‐east regions, characterized by the mutations R1162X, 2183AA→G and 711 + 5G→A, were under the influence of the Venetic culture.

An overview of international literature from cystic fibrosis registries. Part 3. Disease incidence, genotype/phenotype correlation, microbiology, pregnancy, clinical complications, lung transplantation, and miscellanea

This is the third article related to a review of the literature based on data from national cystic fibrosis (CF) patient registries up to June 2008 and covering a total of 115 published studies. It focuses on several topics: CF incidence, genotype/phenotype correlation, microbiology, pregnancy/paternity, clinical complications, lung transplantation, and others. Seventy seven papers meeting the inclusion criteria were found to be related to the topics listed above. Another seven studies, already evaluated in previous papers of this series, were recalled for specific topics. Incidence is described by several studies, results being quite different from one country to another and quite inhomogeneous among regions within the same country. Studies on genetics address the genotype/phenotype correlation and look for a predictive value of CFTR mutations in terms of clinical outcome, with controversial results. Papers on microbiology describe the clinical relevance of different pathogens and their role in the progress of CF lung disease. A few articles give information on the features of CF women undergoing a pregnancy and try to identify the ones associated with a better outcome. Studies on clinical complications discuss prevalence and the role of haemoptysis, pneumothorax, CF related diabetes, ABPA and cancer. Papers on lung transplantation focus on models able to improve the selection criteria for transplantation candidates and the factors linked to post transplantation survival. Finally, several studies deal with a number of interesting topics related to CF epidemiology: clinical trial methodology, quality of care comparison among countries and centers, relationship between diagnosis and age/gender, and evaluation of pharmacological therapy. On the whole, CF Registries have already contributed to important advances in the knowledge of the natural history of CF, establishing the foundations for future improvement in CF research and care.

Comprehensive Cystic Fibrosis Mutation Epidemiology and Haplotype Characterization in a Southern Italian Population

We screened the whole coding region of the cystic fibrosis transmembrane regulator (CFTR) gene in 371 unrelated cystic fibrosis (CF) patients from three regions of southern Italy. Forty‐three mutations detected 91.5% of CF mutated chromosomes by denaturing gradient gel electrophoresis analysis, and three intragenic CFTR polymorphisms predicted a myriad of rare mutations in uncharacterized CF chromosomes. Twelve mutations are peculiar to CF chromosomes from southern Italy: R1158X, 4016insT, L1065P and 711+1G>T are present in 6.3% of CF chromosomes in Campania; G1244E and 852del22 are present in 9.6% of CF chromosomes in Basilicata and 4382delA, 1259insA, I502T, 852del22, 4016insT, D579G, R1158X, L1077P and G1349D are frequent in Puglia (19.6% of CF alleles). Several mutations frequently found in northern Italy (e.g., R1162X, 711+5G>T) and northern Europe (e.g., G551D, I507del and 621+1G>T) are absent from the studied population. The I148T‐3195del6 complex allele was present in two CF chromosomes, whereas I148T was present in both alleles (as a single mutation) in another CF patient and in five CF carriers; this could result from crossover events. The haplotype analysis of three intragenic polymorphisms (IVS8CA, IVS17bTA and IVS17bCA) compared with data from other studies revealed that several mutations (3849+10kbC>T, 1717‐1G>A, E585X, 3272‐26G>A, L558S, 2184insA and R347P) originated from multiple events, whereas others (R1158X and S549R) could be associated with one or more intragenic recombinant events. Given the large population migration from southern Italy, knowledge of the CF molecular epidemiology in this area is an important contribution to diagnosis, counselling and interlaboratory quality control for molecular laboratories worldwide.

Liver expression in cystic fibrosis could be modulated by genetic factors different from the cystic fibrosis transmembrane regulator genotype.

During a multicentric study conducted in Southern Italy, we studied five sets of cystic fibrosis siblings bearing a strongly discordant liver phenotype, three with genotype DeltaF508/R553X, one with genotype DeltaF508/unknown, and one with genotype unknown/unknown. The siblings of each set were raised in the same family environment, and there were no interpair differences in nutritional state or in therapy compliance. All siblings had pancreatic insufficiency and moderate respiratory expression. One sibling of each of the five sets was free of liver involvement, and the other had severe liver expression. Other causes of liver disease (viral, metabolic, and genetic other than cystic fibrosis) were ruled out. Therefore, environmental factors, nutritional state, and therapy compliance are not involved in the liver expression of cystic fibrosis in the five unrelated sibships. This suggests that modifier genes, inherited independently of the cystic fibrosis transmembrane regulator gene, could modulate the liver expression in cystic fibrosis patients.

An overview of international literature from cystic fibrosis registries. Part 4: Update 2011

A total of 53 national cystic fibrosis (CF) patient registry studies published between July 2008 and November 2011 have been reviewed, focusing on the following topics: CF epidemiology, nutrition, microbiology, clinical complications, factors influencing diagnosis and lung disease, effects of socioeconomic status, therapeutic strategy evaluation, clinical trial methodology. The studies describe the clinical characteristics of CF patients, the incidence and prevalence of disease and role of gender gap, as well as the influence of socioeconomic status and environmental factors on clinical outcomes, covering a variety of countries and ethnic groups. Original observations describe patients as they get older, with special reference to the adult presentation of CF and long-term survival. Methodological aspects are discussed, covering the design of clinical trials, survival analysis, auxometry, measures of quality of life, follow up of lung disease, predictability of disease progression and life expectancy. Microbiology studies have investigated the role of selected pathogens, such as Burkholderia species and MRSA. Pulmonary exacerbations are discussed both as a factor influencing morbidity and an endpoint in clinical trials. Finally, some studies give insights on complications, such as CF-related diabetes and hemoptysis, and emerging problems, such as chronic nephropathy.

Phenotype/genotype correlation and cystic fibrosis related diabetes mellitus (Italian Multicenter Study).

BACKGROUND A genotype/phenotype correlation between early onset cystic fibrosis related diabetes (CFRD) and the N1303K mutation of the CF gene was previously identified in a small series of 28 CFRD patients, out of 313 CF patients. PATIENTS AND METHODS In order to confirm the observation, data of 141 CFRD patients out of 1,229 CF patients attending 14 Italian CF centers were collected. All patients were older than 10 years and had been genotyped. RESULTS DeltaF508 was the most frequent mutation (147/282 alleles: 52%) and N1303K the second most frequent mutation (18/282 alleles: 6.3%) in CFRD patients, without significant difference as compared with CF patients without DM (52% vs 48.6% and 6.3% vs 5.1%, respectively). W1282X was the third most frequent mutation in CFRD patients, more frequent than in CF patients without DM (5.3% vs 2%; p<0.001). CONCLUSIONS Unlike the previous study, we did not find a higher frequency of the N1303K mutation in CFRD patients; moreover, data from this large CF series showed a significant correlation between the W1282X mutation and CFRD.

Molecular epidemiology of cystic fibrosis mutations and haplotypes in southern Italy evaluated with an improved semiautomated robotic procedure.

We screened for 22 cystic fibrosis (CF) mutations in DNA from a first cohort of 69 CF patients from southern Italy using a semiautomated allele specific oligonucleotide (ASO) dot blot procedure based on two multiplex PCR amplifications. Seven mutations (delta F508, N1303K, G542X, 1717-1 G-->A, W1282X, 1148T, and R553X) identified 77.6% of CF chromosomes. Detection reached 79.8% with the 2183 AA-->G mutation analysed with the restriction generating PCR method. Thus, we included the 2183 AA-->G mutation in the ASO protocol and set up the conditions to amplify the gene regions that include the eight mutations in a single multiplex PCR reaction. With this method we tested the DNA of the first cohort of 69 CF patients, a second cohort of 63 CF patients, and 300 carrier relatives; we also performed 12 prenatal diagnoses. The results from the 132 CF patients showed differences in the distribution of CF mutations between the south and north of Italy. The XV2c, KM19, and intron 8 VNDR haplotypes suggested the presence, in CF chromosomes bearing undetected mutations, of a limited number of unknown mutations typical of southern Italy. Finally, for six of the eight mutations, we compared the ASO procedure with the methods based on restriction enzymes; the results obtained with the two procedures were identical for all the 57 chromosomes compared.

Validation of a predictive survival model in Italian patients with cystic fibrosis

BACKGROUND In 2001 Liou published a 5-year survival model using CFF Registry data. AIMS To evaluate its validity in predicting survival in Italian CF patients. METHODS In a retrospective study on 945 patients, the 9 variables selected by Liou were analyzed, vital status on December 2008 recorded and observed and expected deaths compared. To develop a new model, patients were randomly divided into a derivation (n=475) and a validation sample (n=470). RESULTS A significant difference was found between observed and expected deaths based on Lious model (62 vs 94), with a 34% reduction in mortality (p<0.05). A new model (based on FEV1, Staphylococcus aureus and Burkholderia cepacia complex infection, number of pulmonary exacerbations/year) was generated, that correctly predicted survival in the validation sample (31 observed vs 29 expected deaths, p=0.660). CONCLUSIONS The Liou model did not adequately predict 5-year survival in our CF population that, compared to the one in which it was originally tested, could benefit from 10 years of improvement in treatments and practice patterns. A new generated model, based on only four variables, was more accurate in predicting 5-year survival in Italian CF patients.