Dataset Information

Use of targeted exome sequencing as a diagnostic tool for Familial Hypercholesterolaemia.

ABSTRACT:

Background

Familial Hypercholesterolaemia (FH) is an autosomal dominant disease, caused by mutations in LDLR, APOB or PCSK9, which results in high levels of LDL-cholesterol (LDL-C) leading to early coronary heart disease. An autosomal recessive form of FH is also known, due to homozygous mutations in LDLRAP1. This study assessed the utility of an exome capture method and deep sequencing in FH diagnosis.

Methods

Exomes of 48 definite FH patients, with no mutation detected by current methods, were captured by Agilent Human All Exon 50Mb assay and sequenced on the Illumina HiSeq 2000 platform. Variants were called by GATK and SAMtools.

Results

The mean coverage of FH genes varied considerably (PCSK9=23x, LDLRAP1=36x, LDLR=56x and APOB=93x). Exome sequencing detected 17 LDLR mutations, including three copy number variants, two APOB mutations, missed by the standard techniques, two LDLR novel variants likely to be FH-causing, and five APOB variants of uncertain effect. Two variants called in PCSK9 were not confirmed by Sanger sequencing. One heterozygous mutation was found in LDLRAP1.

Conclusions

High-throughput DNA sequencing demonstrated its efficiency in well-covered DNA regions, in particular LDLR. This highly automated technology is proving to be effective for heterogeneous diseases and may soon replace laborious conventional methods. However, the poor coverage of gene promoters and repetitive, or GC-rich sequences, remains problematic, and validation of all identified variants is currently required.

SUBMITTER: Futema M

PROVIDER: S-EPMC3475071 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature

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Publications

Use of targeted exome sequencing as a diagnostic tool for Familial Hypercholesterolaemia.

Futema Marta M Plagnol Vincent V Whittall Ros A RA Neil H Andrew W HA Humphries Steve Eric SE

Journal of medical genetics 20121001 10

<h4>Background</h4>Familial Hypercholesterolaemia (FH) is an autosomal dominant disease, caused by mutations in LDLR, APOB or PCSK9, which results in high levels of LDL-cholesterol (LDL-C) leading to early coronary heart disease. An autosomal recessive form of FH is also known, due to homozygous mutations in LDLRAP1. This study assessed the utility of an exome capture method and deep sequencing in FH diagnosis.<h4>Methods</h4>Exomes of 48 definite FH patients, with no mutation detected by curren ...[more]

PMID: 23054246

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Project description:ImportanceComplex disorders, such as bipolar disorder (BD), likely result from the influence of both common and rare susceptibility alleles. While common variation has been widely studied, rare variant discovery has only recently become feasible with next-generation sequencing.ObjectiveTo utilize a combined family-based and case-control approach to exome sequencing in BD using multiplex families as an initial discovery strategy, followed by association testing in a large case-control meta-analysis.Design, setting, and participantsWe performed exome sequencing of 36 affected members with BD from 8 multiplex families and tested rare, segregating variants in 3 independent case-control samples consisting of 3541 BD cases and 4774 controls.Main outcomes and measuresWe used penalized logistic regression and 1-sided gene-burden analyses to test for association of rare, segregating damaging variants with BD. Permutation-based analyses were performed to test for overall enrichment with previously identified gene sets.ResultsWe found 84 rare (frequency <1%), segregating variants that were bioinformatically predicted to be damaging. These variants were found in 82 genes that were enriched for gene sets previously identified in de novo studies of autism (19 observed vs. 10.9 expected, P = .0066) and schizophrenia (11 observed vs. 5.1 expected, P = .0062) and for targets of the fragile X mental retardation protein (FMRP) pathway (10 observed vs. 4.4 expected, P = .0076). The case-control meta-analyses yielded 19 genes that were nominally associated with BD based either on individual variants or a gene-burden approach. Although no gene was individually significant after correction for multiple testing, this group of genes continued to show evidence for significant enrichment of de novo autism genes (6 observed vs 2.6 expected, P = .028).Conclusions and relevanceOur results are consistent with the presence of prominent locus and allelic heterogeneity in BD and suggest that very large samples will be required to definitively identify individual rare variants or genes conferring risk for this disorder. However, we also identify significant associations with gene sets composed of previously discovered de novo variants in autism and schizophrenia, as well as targets of the FRMP pathway, providing preliminary support for the overlap of potential autism and schizophrenia risk genes with rare, segregating variants in families with BD.

Dataset Information

Use of targeted exome sequencing as a diagnostic tool for Familial Hypercholesterolaemia.

Background

Methods

Results

Conclusions

Publications

Use of targeted exome sequencing as a diagnostic tool for Familial Hypercholesterolaemia.

Similar Datasets

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