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DG Exome Trio®

Whole-exome genetic analysis of the child and both parents

Maximum diagnostic performance available for complex diseases

A trio whole-exome study is a genetic test that examines all the coding regions of DNA (the exons) from a patient and their two parents. Its primary goal is to identify genetic variants that may be associated with diseases, particularly those that are rare or difficult to diagnose.

Performing a trio whole-exome sequencing facilitates the identification of de novo variants—that is, genetic changes that appear for the first time in the patient and are often responsible for rare or complex diseases. Furthermore, by comparing the patient’s results with the parents’ DNA, inherited variants that do not cause disease can be ruled out, reducing false positives and the number of variants of uncertain clinical significance (VUS). For all these reasons, trio whole-exome sequencing allows for a more accurate and reliable interpretation of genetic findings, increasing the likelihood of obtaining a clear diagnosis and more effectively guiding the clinical management of patients and family genetic counseling.

Catalog of genetic studies
Learn more about our genetic diagnostic studies by downloading the catalog.
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Service features

Features
Advice
Pre-analysis support for the choice of the best diagnostic approach for each patient and post-analysis support for the correct diagnostic interpretation of the results.
Genes
Sequencing of all coding genomic regions of more than 20,000 genes in the patient's sample and those of both parents.
Bookstore
Agilent Sure Select Human All Exon V8.
Mitochondrial DNA
For studies requiring mitochondrial DNA analysis we use the Twist Human Core Exome probe + RefSeq Panel + mitDNA Panel.
Coverage
  • Complete theoretical coverage for protein coding regions collected in RefSeq, CCDS, GENCODE1 databases.
  • Medium coverage 100-150x.
Specificity
≥99% for all reported variants. Pathogenic and Probably Pathogenic variants with low coverage and/or not well-defined heterozygosity are validated by Sanger sequencing.
Bioinformatics analysis
Identification of SNVs, Indels and CNVs2 using our Genome One software. Alignment against the GRCh38/hg38 version of the reference genome. Variant calling and annotation with information from different functional (RefSeq, Pfam), population (1000 Genomes, dbSNP, ESP6500, ExAC, gnomAD), in silico functional impact prediction (dbNSFP, dbscSNV) and clinical information (OMIM, ClinVar, HPO) databases.
Genotype-first interpretation
The variants of interest are compared with the patient's clinical picture. This approach allows the identification of new genes with clinical significance and the detection of new variants or genes associated with the pathology studied that have not yet been described.
Report of results
  • Conclusive and with specific clinical recommendations in each case.
  • Interpretation of variants based on clinical evidence and according to public and reference databases.
  • Pathogenic and probably pathogenic variants are reported according to the American College of Medical Genetics and Genomics (ACMG) classification.
  • Variants of Uncertain Clinical Significance (VUS) are reported only in those cases in which they can fully or partially explain the patient's clinical presentation.
  • Benign and Probably Benign variants will be available upon request3.
Valid samples
EDTA-anticoagulated blood, saliva collected using an Isohelix or Oragene kit, and purified DNA.
Delivery time
35 working days.

CNVs: Copy Number Variations; MLPA: Multiplex Ligation-dependent Probe Amplification; 1AgilentSureSelect Human All Exon V8 covers 100% of the protein coding sequences from CCDS version 22, GENCODE version 31 and RefSeq version 95. 2CNVsidentified with a Pathogenic or Probably Pathogenic classification may be validated by MLPA or other molecular technique upon request. 3Toreceive the complete list, please send an email to genetica@dreamgenics.com.

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If you would like to request a quotation, or if you have any questions, please do not hesitate to contact us and we will help you.
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When is it indicated?

Whole-exome sequencing of a trio is primarily recommended when the goal is to identify the genetic cause of complex or rare diseases, especially in cases where conventional testing has been insufficient.

In general, trio exome sequencing is recommended when maximum accuracy is required in the interpretation of variants, as it optimizes the identification of pathogenic changes and improves the clinical diagnosis rate compared to analyzing the patient’s whole exome alone.

Some of the main reasons for requesting a DG Exome Trio® test include:

  • When a patient presents with multiple physical, neurological, or metabolic abnormalities without a clear clinical diagnosis.
  • In cases of pediatric neurological or developmental disorders where de novo variants are common, such as global developmental delay, refractory epilepsy, autism spectrum disorders, or early-onset neurodegenerative diseases.
  • When there is no family history of the disease and a de novo mutation is suspected.
  • When previous diagnostic tests fail to identify the cause of the illness.

Additional Services

Scientific knowledge about the involvement of genetic variants in disease development is constantly evolving. In addition, the clinical presentation of a disease may change over time. Therefore, we offer variant reassessment and case reanalysis services.

Features
Re-evaluation of VUS
  • We performed the classification review according to ACMG criteria of variants initially reported as of Uncertain Clinical Significance (VUS) at 12 months and issued a new report in case of changes in their pathogenicity.
  • Additionally, this service can be performed upon request of the physician.
  • Deadline for delivery of the new report: 15 working days.
Reanalysis of the case
  • Samples from the patient and both parents are reanalyzed from the FASTQ files, taking into account the new clinical information provided by the physician. The goal is to identify new clinically relevant variants that may explain or contribute to the diagnosis, thanks to improvements in the bioinformatics pipeline and updates to the information contained in the databases used for annotation.
  • This service is performed only upon request of the physician.
  • Delivery time of the new report: 21 working days.
Raw data
Raw and processed whole-exome data (FASTQ, BAM, and VCF files, along with filtered and annotated variant files in XLS format) for the patient and both parents are available upon request.

To request one of these services, please contact us by writing an email to genetica@dreamgenics.com.

Need more information?
Please don't hesitate to contact us—we'll be happy to help.
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