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Cystic fibrosis is the most common life-limiting autosomal recessive disease in western countries with an incidence of 1:2500 in United States and 1:1000 in some European countries. Similar incidences were noted for the Middle East with variations from 1 in 2560 to 1 in 15,876 according to the degree of consanguinity. This is a preliminary systematic study that aims to assess the incidence and carrier rate of cystic fibrosis in the Middle Eastern Lebanese population; known for a high frequency of consanguinity. One hundred thirteen DNA samples were collected from neonatal blood cards obtained from newborns to healthy unrelated families with no previous history of Cystic fibrosis. Screening for Cystic Fibrosis-causing pathogenic variants was performed using next generation sequencing, and 17 different single nucleotide variants were detected, including six pathogenic and likely pathogenic. 5.5%-7% newborns were found to be carriers of a variant strongly suggestive of pathogenicity and comparable to published literature worldwide. This pilot analysis highlights the challenging interpretation of CFTR variants in a country underrepresented by large ethnic population analyses, and stresses the importance of premarital screening programs for Cystic fibrosis., (© 2021 John Wiley & Sons Ltd/University College London.)

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., (Copyright © 2010 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.)

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.

Genetic testing for cystic fibrosis and CFTR-related disorders mostly relies on laborious molecular tools that use Sanger sequencing to scan for mutations in the CFTR gene. We have explored a more efficient genetic screening strategy based on next-generation sequencing ( NGS) of the CFTR gene. We validated this approach in a cohort of 177 patients with previously known CFTR mutations and polymorphisms. Genomic DNA was amplified using the Ion AmpliSeq™ CFTR panel. The DNA libraries were pooled, barcoded, and sequenced using an Ion Torrent PGM sequencer. The combination of different robust bioinformatics tools allowed us to detect previously known pathogenic mutations and polymorphisms in the 177 samples, without detecting spurious pathogenic calls. In summary, the assay achieves a sensitivity of 94.45% (95% CI: 92% to 96.9%), with a specificity of detecting nonvariant sites from the CFTR reference sequence of 100% (95% CI: 100% to 100%), a positive predictive value of 100% (95% CI: 100% to 100%), and a negative predictive value of 99.99% (95% CI: 99.99% to 100%). In addition, we describe the observed allelic frequencies of 94 unique definitely and likely pathogenic, uncertain, and neutral CFTR variants, some of them not previously annotated in the public databases. Strikingly, a seven exon spanning deletion as well as several more technically challenging variants such as pathogenic poly-thymidine-guanine and poly-thymidine (poly- TG-T) tracts were also detected. Targeted NGS is ready to substitute classical molecular methods to perform genetic testing on the CFTR gene. [ABSTRACT FROM AUTHOR]