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T Casals

Publications and source records attributed to T Casals.

At least 19 recordsLinked to original sources
PubMed2005

Molecular evaluation of CFTR sequence variants in male infertility of testicular origin.

Although the involvement of the CFTR gene has been well established in congenital agenesia of vas deferens, its role in non-obstructive (NOb) infertility is still a matter of debate. In order to definitively define the involvement of the CFTR gene in spermatogenic impairment and a potential synergistic contribution to known genetic and clinical factors, genetic variants in the entire coding sequence and the immediately flanking regions of the CFTR gene, along with a thorough clinical evaluation, were analysed in 83 NOb infertile patients and 87 clinically well-defined fertile individuals as controls. The results of our study showed no statistical difference between CFTR carrier frequency in the infertile and fertile population. Specifically, the IVS8-6(5T) allele carrier frequency was similar in NOb infertile patients when compared with fertile men, but it is noteworthy that, when fertile men were classified into having optimal and suboptimal fertility, no 5T allele was found among the 35 men with optimal fertility parameters. In conclusion, extensive CFTR analysis in infertile individuals and fertile population as adequate control definitively excludes the involvement of the CFTR gene variants in sperm production and stresses the importance of carefully identifying those individuals with obstructive defects, in whom CFTR screening will be beneficial.

Base Sequence↗
PubMed2005

Genotype-phenotype correlation for pulmonary function in cystic fibrosis.

BACKGROUND: Since the CFTR gene was cloned, more than 1000 mutations have been identified. To date, a clear relationship has not been established between genotype and the progression of lung damage. A study was undertaken of the relationship between genotype, progression of lung disease, and survival in adult patients with cystic fibrosis (CF). METHODS: A prospective cohort of adult patients with CF and two CFTR mutations followed up in an adult cystic fibrosis unit was analysed. Patients were classified according to functional effects of classes of CFTR mutations and were grouped based on the CFTR molecular position on the epithelial cell surface (I-II/I-II, I-II/III-V). Spirometric values, progression of lung disease, probability of survival, and clinical characteristics were analysed between groups. RESULTS: Seventy four patients were included in the study. Patients with genotype I-II/I-II had significantly lower current spirometric values (p < 0.001), greater loss of pulmonary function (p < 0.04), a higher proportion of end-stage lung disease (p < 0.001), a higher risk of suffering from moderate to severe lung disease (odds ratio 7.12 (95% CI 1.3 to 40.5)) and a lower probability of survival than patients with genotype I-II/III, I-II/IV and I-II/V (p < 0.001). CONCLUSIONS: The presence of class I or II mutations on both chromosomes is associated with worse respiratory disease and a lower probability of survival.

Adult↗
PubMed2005

[Cystic fibrosis presenting as acute recurrent pancreatitis].

Cystic fibrosis is a multiorgan autosomal recessive disease resulting from mutations in a gene located on the long arm of chromosome 7. The disease is usually diagnosed in the first few years of life when it typically presents with severe pulmonary manifestations and pancreatic insufficiency; however, a small percentage of patients with less dramatic symptoms is not diagnosed until adolescence or even adulthood. The genotype of each patient seems to influence the various forms of clinical presentation. Although uncommon, acute recurrent pancreatitis can be one of the forms of delayed presentation of cystic fibrosis. We report the case of an 17-year-old man who was diagnosed with cystic fibrosis after presenting 2 episodes of acute pancreatitis without associated pancreatic insufficiency. Subsequent study also revealed nasal polyps.

Acute Disease↗
PubMed2004

Bronchiectasis in adult patients: an expression of heterozygosity for CFTR gene mutations?

While all patients with cystic fibrosis (CF) have mutations in both CFTR alleles, often only one CFTR change is detected in patients with other lung disorders. The aim of this study was to investigate whether heterozygosity for CFTR mutations could be a determinant risk factor in the development of bronchiectasis in adult patients. We have performed the CFTR gene analysis in a cohort of 55 bronchiectasis adult patients with unknown etiology. The 5T variant (TG)m and the M470V polymorphisms were also analyzed. A general population in which the same molecular analysis was previously performed was used as the control group. The mutational spectrum of patients was also compared with that found in our CF population. CFTR mutations/variants were found in 20 patients (36%), 14 with only one mutant gene (25%). All six patients colonized by Staphylococcus aureus presented with at least one CFTR change (p = 0.001). No statistical significance was observed between patients with and without mutations for other clinical features. The 5T variant was found in four patients. Additionally, 90% of patients with mutations had the more functional M470 allele (p < 0.001). These results suggest the involvement of the CFTR gene in bronchiectasis of unknown etiology in adult patients.

Adult↗
PubMed2001

ATB(0)/SLC1A5 gene. Fine localisation and exclusion of association with the intestinal phenotype of cystic fibrosis.

The Na+-dependent amino acid transporter named ATB(0) was previously found to be located in 19q13.3 by fluorescence in situ hybridisation. Genetic heterogeneity in the 19q13.2-13.4 region, syntenic to the Cystic Fibrosis Modulator Locus 1 (CFM1) in mouse, seemed to be associated to the intestinal phenotypic variation of cystic fibrosis (CF). We performed fine chromosomal mapping of ATB(0) on radiation hybrid (RH) panels G3 and TNG. Based on the most accurate location results from TNG-RH panel, mapping analysis evidenced that ATB(0) is localised between STS SHGC-13875 (D19S995) and STS SHGC-6138 in 19q13.3, that corresponds with the immediately telomeric/distal segment of the strongest linkage region within the human CFM1 (hCFM1) syntenic region. Regarding to the genomic structure and exon organisation, our results show that the ATB(0) gene is organised into eight exons. The knowledge of the genomic structure allowed us to perform an exhaustive mutational analysis of the gene. Evaluation of the possible implication of ATB(0) in the intestinal phenotype of CF was performed on the basis of the functional characteristics of the encoded protein, its apparent relevance to meconium ileus (MI) and position in relation to the hCFM1 syntenic region. We have analysed this gene in samples from CF patients with and without MI. Several sequence variations in the ATB(0) gene were identified, although none of them seemed to be related to the intestinal phenotype of CF. Even though no particular allele or haplotype in ATB(0) appears to be associated to CF-MI disease, new SNPs identified should be useful in segregation and linkage disequilibrium analyses in families affected by other disorders caused by the impairment of neutral amino acid transport.

Alleles↗
PubMed2001

Adenosine triphosphate-binding cassette superfamily transporter gene expression in severe male infertility.

Cystic fibrosis transmembrane regulator (CFTR), multidrug-resistant (MDR)1, and multidrug resistance-associated (MRP) proteins belong to the ATP-binding cassette (ABC) transporter superfamily. A compensatory regulation of MDR1 and CFTR gene expression has been observed in CFTR knockout rodent intestine and in an epithelial cell line of human colon, whereas a high homology and similar anion binding site are shared by MRP and CFTR proteins. To provide better insight into the relationship among the expression behavior in vivo of the three genes in human testis, analysis of MDR1 and MRP gene expression in testicular biopsies was performed and related to the presence of CFTR gene mutations in congenital absence of the vas deferens (CAVD: n = 20) and non-CAVD (n = 30) infertile patients with azoospermia or severe oligozoospermia. A CFTR mutation analysis performed in both groups of patients supported the involvement of CFTR gene mutations in CAVD phenotype (85%) and in defective spermatogenesis (19%). Quantitative reverse transcription-polymerase chain reaction analysis of testicular tissue showed a CFTR-independent MDR1 and MRP gene expression in human testis, suggesting that the mechanisms underlying CFTR gene regulation in testis are different from those in intestine. These findings should contribute to the understanding of patterns of in vivo expression of CFTR, MDR1, and MRP genes in CFTR-related infertility.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Cystic fibrosis transmembrane regulator (CFTR) DeltaF508 mutation and 5T allele in patients with chronic pancreatitis and exocrine pancreatic cancer. PANKRAS II Study Group.

BACKGROUND: An increased risk of chronic pancreatitis has been described among carriers of the cystic fibrosis transmembrane regulator (CFTR) mutation. In addition, patients with cystic fibrosis may have a higher risk of exocrine pancreatic cancer. AIMS: To determine the prevalence of the DeltaF508 mutation and 5T allele, the most common CFTR disease related variants, and to assess their association with lifestyle factors in an unselected series of patients with chronic pancreatitis or pancreatic cancer. SUBJECTS: Patients recruited to the multicentre PANKRAS II study with a diagnosis of chronic pancreatitis and pancreatic cancer from whom normal DNA was available. METHODS: The DeltaF508 mutation and 5T allele were analysed using polymerase chain reaction amplified normal DNA. Information on clinical and lifestyle factors was obtained through personal interviews. RESULTS: Among patients with pancreatitis, no DeltaF508 alleles were found and the prevalence of the 5T allele was 10.5%, similar to that described in the general population. Among patients with pancreatic cancer, the prevalence of the DeltaF508 mutation and the 5T allele was 2.4% and 5.5%, respectively. 5T allele carriers with cancer consumed significantly less alcohol than non-carriers (p=0.038). CONCLUSIONS: Our findings do not support the view that the DeltaF508 mutation and 5T allele confer a higher risk of chronic pancreatitis or pancreatic cancer. Nevertheless, our data suggest that interactions between CFTR polymorphism and environmental factors may play a role in the pathogenesis of these diseases. Our study emphasises the need for a multinational study to conclusively establish the role of CFTR variants as genetic susceptibility factors for chronic pancreatitis and pancreatic cancer.

Adenocarcinoma↗
PubMed2000

Characterization of a novel 21-kb deletion, CFTRdele2,3(21 kb), in the CFTR gene: a cystic fibrosis mutation of Slavic origin common in Central and East Europe.

We report a large genomic deletion of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, viz., a deletion that is frequently observed in Central and Eastern Europe. The mutation, termed CFTRdele2,3(21 kb), deletes 21,080 bp spanning introns 1-3 of the CFTR gene. Transcript analyses have revealed that this deletion results in the loss of exons 2 and 3 in epithelial CFTR mRNA, thereby producing a premature termination signal within exon 4. In order to develop a simple polymerase chain reaction assay for this allele, we defined the end-points of the deletion at the DNA sequence level. We next screened for this mutation in a representative set of European and European-derived populations. Some 197 CF patients, including seven homozygotes, bearing this mutation have been identified during the course of our study. Clinical evaluation of CFTRdele2,3(21 kb) homozygotes and a comparison of compound heterozygotes for deltaF508/CFTRdele2,3(21 kb) with pairwise-matched deltaF508 homozygotes indicate that this deletion represents a severe mutation associated with pancreatic insufficiency and early age at diagnosis. Current data show that the mutation is particularly common in Czech (6.4% of all CF chromosomes), Russian (5.2%), Belorussian (3.3%), Austrian (2.6%), German (1.5%), Polish (1.5%), Slovenian (1.5%), Ukrainian (1.2%), and Slovak patients (1.1%). It has also been found in Lithuania, Latvia, Macedonia and Greece and has sporadically been observed in Canada, USA, France, Spain, Turkey, and UK, but not in CF patients from Bulgaria, Croatia, Romania or Serbia. Haplotype analysis has identified the same extragenic CF-haplotype XV-2c/KM. 19 "A" and the same infrequent intragenic microsatellite haplotype 16-33-13 (IVS8CA-IVS 17bTA-IVS 17bCA) in all examined CFTRdele2,3(21 kb) chromosomes, suggesting a common origin for this deletion. We conclude that the 21-kb deletion is a frequent and severe CF mutation in populations of Eastern- and Western-Slavic descent.

Alleles↗
PubMed2000

A new approach for identifying non-pathogenic mutations. An analysis of the cystic fibrosis transmembrane regulator gene in normal individuals.

Given q as the global frequency of the alleles causing a disease, any allele with a frequency higher than q minus the cumulative frequency of the previously known disease-causing mutations (threshold) cannot be the cause of that disease. This principle was applied to the analysis of cystic fibrosis transmembrane conductance regulator (CFTR) mutations in order to decide whether they are the cause of cystic fibrosis. A total of 191 DNA samples from random individuals from Italy, France, and Spain were investigated by DGGE (denaturing gradient gel electrophoresis) analysis of all the coding and proximal non-coding regions of the gene. The mutations detected by DGGE were identified by sequencing. The sample size was sufficient to select essentially all mutations with a frequency of at least 0.01. A total of 46 mutations was detected, 20 of which were missense mutations. Four new mutations were identified: 1341+28 C/T, 2082 C/T, L1096R, and I11131V. Thirteen mutations (125 G/C, 875+40 A/G, TTGAn, IVS8-6 5T, IVS8-6 9T, 1525-61 A/G, M470V, 2694 T/G, 3061-65 C/A, 4002 A/G, 4521 G/A, IVS8 TG10, IVS8 TG12) were classified as non-CF-causing alleles on the basis of their frequency. The remaining mutations have a cumulative frequency far exceeding q; therefore, most of them cannot be CF-causing mutations. This is the first random survey capable of detecting all the polymorphisms of the coding sequence of a gene.

Cystic Fibrosis Transmembrane Conductance Regulato↗
PubMed2000

Heterogeneity for mutations in the CFTR gene and clinical correlations in patients with congenital absence of the vas deferens.

Congenital absence of the vas deferens (CAVD) is a heterogeneous disorder, largely due to mutations in the cystic fibrosis (CFTR) gene. Patients with unilateral absence of the vas deferens (CUAVD) and patients with CAVD in association with renal agenesis appear to have a different aetiology to those with isolated CAVD. We have studied 134 Spanish CAVD patients [110 congenital bilateral absence of the vas deferens (CBAVD) and 24 CUAVD], 16 of whom (six CBAVD, 10 CUAVD) had additional renal anomalies. Forty-two different CFTR mutations were identified, seven of them being novel. Some 45% of the CFTR mutations were specific to CAVD, and were not found in patients with cystic fibrosis or in the general Spanish population. CFTR mutations were detected in 85% of CBAVD patients and in 38% of those with CUAVD. Among those patients with renal anomalies, 31% carried one CFTR mutation. Anomalies in seminal vesicles and ejaculatory ducts were common in patients with CAVD. The prevalence of cryptorchidism and inguinal hernia appeared to be increased in CAVD patients, as well as nasal pathology and frequent respiratory infections. This study confirms the molecular heterogeneity of CFTR mutations in CAVD, and emphasizes the importance of an extensive CFTR analysis in these patients. In contrast with previous studies, this report suggests that CFTR might have a role in urogenital anomalies.

Abnormalities, Multiple↗
PubMed1999

Missense mutations in the cystic fibrosis gene in adult patients with asthma.

Asthma is a complex genetic disorder that affects 5% of adults and 10% of children worldwide. The complete characterization of the cystic fibrosis transmembrane conductance regulator (CFTR) gene identified missense mutations in 15% of 144 unrelated adult patients with asthma, but in none of 41 subjects from the general population. The four more common mutations were analyzed in an extended sample consisting of 184 individuals from the general population and did not show a significant difference in frequency. The hyperfunctional CFTR M470 allele was detected in 90% of patients with CFTR missense mutations, but in 63% of subjects from the general population and 63% of asthma patients without CFTR mutations. None of the patients with missense mutations had the 5T allele of intron 8 of CFTR, responsible for low CFTR levels, while it was detected in 8% of asthma patients without CFTR mutations and in 9% of subjects from the general population. These findings suggest a putative role for a combination of CFTR missense mutations, including the M470 allele, in the genetic variability of asthma.

Adult↗
PubMed1999

Allele frequencies in a worldwide survey of a CA repeat in the first intron of the CFTR gene.

A dinucleotide CA repeat within intron 1 of the CFTR gene has recently been identified. We have determined the allele frequencies of this polymorphism in samples from 18 populations covering all major geographical areas, with a total of 1,816 chromosomes. When considering allele distributions, African populations presented a wider range of alleles than other populations and also presented higher expected heterozygosities. Analysis of molecular variance showed that 8.04% of the genetic variance in this locus could be attributed to differences among populations. We concluded that the polymorphism in the CA repeat in intron 1 of the CFTR gene is highly informative in populations from all geographical regions of the world. Thus, it can be applied to family studies of unknown mutations causing cystic fibrosis (CF) and can provide valuable information for genetic counseling. Moreover, its analysis should be included in the haplotypic analysis of known CF mutations.

Alleles↗
PubMed1998

Testicular CFTR splice variants in patients with congenital absence of the vas deferens.

The involvement of the five thymidine (5T) variant in intron 8 of the cystic fibrosis membrane regulator (CFTR) gene in congenital bilateral absence of the vas deferens (CBAVD) phenotype has been extensively demonstrated. This variant leads to alternative splicing of the CFTR gene which results in a wild-type transcript and one without exon 9. Little is known about expression of the CFTR gene in the testis. We analysed the level of the aberrantly spliced transcripts in testicular biopsies and correlated it with disease expression. Quantitative RT-PCR analysis in testicular biopsies from control and CBAVD patients showed a correlation between the length of the IVS8-6(T) n tract and the level of alternatively spliced transcripts. Results from histological analysis also suggest an involvement of the alternative transcript in the spermatogenic status of patients, leading to a decreased number of mature sperm forms in the tubule.

Alternative Splicing↗