Dataset Information

Identification of a novel large deletion and other copy number variations in the CFTR gene in patients with Cystic Fibrosis from a multiethnic population.

ABSTRACT:

Background

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). There are over 2000 different pathogenic and non-pathogenic variants described in association with a broad clinical heterogeneity. The most common types of mutations in this gene are single nucleotide substitutions or small deletions and insertions. However, large rearrangements, such as large duplications or deletions, are also a possible cause of CF; these variations are rarely tested in routine screenings, and much of them remain unidentified in some populations, especially those with high ethnic heterogeneity.

Methods

The present study utilized the Multiplex Ligation-dependent Probe Amplification (MLPA) technique for the detection of duplications and deletions in 165 CF patients from the Rio de Janeiro State (Brazil), which after extensive mutational screening, still exhibited one or two unidentified CF alleles.

Results

Five patients with alterations in MLPA signals were detected. After validation, we identified three copy number variations, one large duplication (CFTRdup2-3) and two large deletions (CFTRdel25-26 and CFTRdel25-27-CTTNBP2). Two detected deletions were not validated. They were false positives caused by a small deletion of 18 base pairs (232del18) and a point mutation (S168L) in the probe binding site.

Conclusion

Our results highlight the importance of screening for large rearrangements in CF cases with no or only one CFTR mutation defined.

SUBMITTER: Martins RDS

PROVIDER: S-EPMC6625342 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

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Publications

Identification of a novel large deletion and other copy number variations in the CFTR gene in patients with Cystic Fibrosis from a multiethnic population.

Martins Raisa da Silva RDS Campos Junior Mario M Dos Santos Moreira Aline A Marques Zembrzuski Verônica V da Fonseca Ana Carolina Proença ACP Abreu Gabriella de Medeiros GM Cabello Pedro Hernan PH de Cabello Giselda Maria Kalil GMK

Molecular genetics & genomic medicine 20190614 7

<h4>Background</h4>Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). There are over 2000 different pathogenic and non-pathogenic variants described in association with a broad clinical heterogeneity. The most common types of mutations in this gene are single nucleotide substitutions or small deletions and insertions. However, large rearrangements, such as large duplications or deletions, are also a possible cause of CF; these vari ...[more]

PMID: 31199594

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Project description:The populations of the Arabian Peninsula remain the least represented in public genetic databases, both in terms of single nucleotide variants and of larger genomic mutations. We present the first high-resolution copy number variation (CNV) map for a Gulf Arab population, using a hybrid approach that integrates array genotyping intensity data and next-generation sequencing reads to call CNVs in the Qatari population.CNVs were detected in 97 unrelated Qatari individuals by running two calling algorithms on each of two primary datasets: high-resolution genotyping (Illumina Omni 2.5M) and high depth whole-genome sequencing (Illumina PE 100bp). The four call-sets were integrated to identify high confidence CNV regions, which were subsequently annotated for putative functional effect and compared to public databases of CNVs in other populations. The availability of genome sequence was leveraged to identify tagging SNPs in high LD with common deletions in this population, enabling their imputation from genotyping experiments in the future.Genotyping intensities and genome sequencing data from 97 Qataris were analyzed with four different algorithms and integrated to discover 16,660 high confidence CNV regions (CNVRs) in the total population, affecting ~28 Mb in the median Qatari genome. Up to 40% of all CNVs affected genes, including novel CNVs affecting Mendelian disease genes, segregating at different frequencies in the 3 major Qatari subpopulations, including those with Bedouin, Persian/South Asian, and African ancestry. Consistent with high consanguinity levels in the Bedouin subpopulation, we found an increased burden for homozygous deletions in this group. In comparison to known CNVs in the comprehensive Database of Genomic Variants, we found that 5% of all CNVRs in Qataris were completely novel, with an enrichment of CNVs affecting several known chromosomal disorder loci and genes known to regulate sugar metabolism and type 2 diabetes in the Qatari cohort. Finally, we leveraged the availability of genome sequence to find suitable tagging SNPs for common deletions in this population.We combine four independently generated datasets from 97 individuals to study CNVs for the first time at high-resolution in a Gulf Arab population.

Dataset Information

Identification of a novel large deletion and other copy number variations in the CFTR gene in patients with Cystic Fibrosis from a multiethnic population.

Background

Methods

Results

Conclusion

Publications

Identification of a novel large deletion and other copy number variations in the CFTR gene in patients with Cystic Fibrosis from a multiethnic population.

Similar Datasets

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