Detection of CFTR mutations using PCR/ARMS in a sample of Algerian population.

Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians. Wrongly considered as a European disease, CF is found in Algeria; but the literature data on the clinical profile and the spectrum of CFTR gene mutations are poor. In this study we investigate twenty-four unrelated Algerian families, with at least one child with CF. DNA extracts from blood samples of patients and parents were screened for CFTR gene mutations using Elucigene CF30 Kit which is based on a PCR/ARMS technique. Only five different mutations were identified. On the 48 alleles studied, most common mutations were: c.1521_1523delCTT (F508del) 18.75%, c.579+1G>T (711+1G>T) 12.5%, c.1624G>T (G542X) 10.41%, c.3909C>G (N1303K) 4%, and c.1652G>A (G551D) 2%. The Elucigene CF30 kit highlights a portion of CFTR mutations in the Algerian population. It remains important for a first screening as it reveals the most common mutations. All this information is of interest for genetic testing and genetic counseling in Algeria and in European countries where immigration from the Maghreb is common.

CFTR mutation combinations producing frequent complex alleles with different clinical and functional outcomes.

Genotype-phenotype correlations in cystic fibrosis (CF) may be difficult to establish because of phenotype variability, which is associated with certain CF transmembrane conductance regulator (CFTR) gene mutations and the existence of complex alleles. To elucidate the clinical significance of complex alleles involving p.Gly149Arg, p.Asp443Tyr, p.Gly576Ala, and p.Arg668Cys, we performed a collaborative genotype-phenotype correlation study, collected epidemiological data, and investigated structure-function relationships for single and natural complex mutants, p.[Gly576Ala;Arg668Cys], p.[Gly149Arg;Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys]. Among 153 patients carrying at least one of these mutations, only three had classical CF and all carried p.Gly149Arg in the triple mutant. Sixty-four had isolated infertility and seven were healthy individuals with a severe mutation in trans, but none had p.Gly149Arg. Functional studies performed on all single and natural complex mutants showed that (1) p.Gly149Arg results in a severe misprocessing defect; (2) p.Asp443Tyr moderately alters CFTR maturation; and (3) p.Gly576Ala, a known splicing mutant, and p.Arg668Cys mildly alter CFTR chloride conductance. Overall, the results consistently show the contribution of p.Gly149Arg to the CF phenotype, and suggest that p.[Arg668Cys], p.[Gly576Ala;Arg668Cys], and p.[Asp443Tyr;Gly576Ala;Arg668Cys] are associated with CFTR-related disorders. The present study emphasizes the importance of comprehensive genotype-phenotype and functional studies in elucidating the impact of mutations on clinical phenotype.

Mutational spectrum of cystic fibrosis in the Lebanese population.

BACKGROUND: Cystic fibrosis (CF) is the most common autosomal recessive disease in Caucasians; it is however, considered to be rare in the Arab populations. Reports of the cystic fibrosis transmembrane regulator (CFTR) mutations from Arabs, especially from the Lebanese population, are limited. METHODS: Twenty-two unrelated Lebanese families, with at least one child with CF, were studied. DNA extracts from blood samples of patients and parents were screened for CFTR gene mutations. RESULTS: Eleven different mutations were identified. Of the 44 alleles studied, the most common mutations were: F508del (34%), N1303K (27%), W1282X (7%), and S4X (7%). Five mutations - not previously reported in the Lebanese population - were identified; these are: S549N, G542X, 2043delG, 4016insG, and R117H-7T. CONCLUSIONS: The most common CFTR mutations in addition to five mutations not previously described in the Lebanese population were identified. Identification of CFTR mutations in the Lebanese population is important for molecular investigations and genetic counseling.

Cystic fibrosis: a new mutation in the Lebanese population.

BACKGROUND: Cystic fibrosis is the most common autosomal recessive disorder in Caucasians. Little has been reported on its occurrence in Arab and Lebanese populations where mutation distribution seems to differ from that of Europeans. We report on the occurrence of a frameshift mutation 4016insG in two Lebanese Muslim siblings, products of consanguineous parents. This mutation generates a stop codon instead of Arginine-1301 and has never been reported before. METHODS: Both probands manifested early onset of severe respiratory and pancreatic involvement. DNA analysis was performed by PCR and sequencing for exons 1, 4, 10, 11, 20, 21 of the CFTR gene. RESULTS: Both probands were found to be homozygous for the 4016insG. Their parents were both heterozygous for the same mutation. CONCLUSION: The frameshift mutation reported in this article is being described for the first time.

Unexpected diagnosis of cystic fibrosis at liver biopsy: a report of four pediatric cases.

We report here four cases of pediatric patients in whom the diagnosis of cystic fibrosis was made only after the histological examination of a liver specimen obtained by biopsy (three cases) or at autopsy (one case). There were two boys and two girls, aged 13 months to 7.5 years. None had a personal or familial history suggestive of cystic fibrosis. One patient, presenting with myocardial lesion and hepatomegaly, died of heart failure; at autopsy, the liver showed a typical aspect of focal biliary cirrhosis. In the three other cases, liver disease was the only manifestation of cystic fibrosis at the time of diagnosis. Liver biopsy examination showed focal biliary cirrhosis in one case and massive steatosis in two. In all four cases, the diagnosis was confirmed by the existence of known pathogenic mutations in the CFTR gene. The evolution was variable; one patient had progressive liver disease with severe portal hypertension after 7 years; another one had lung complications after 1 year. In conclusion, our experience recalls that the diagnosis of cystic fibrosis must be considered in children presenting with unexplained liver disease; its confirmation by molecular techniques makes it possible to set up an appropriate follow-up.