specifications
We use the Illumina® Global Screening Array (GSA) - a DNA microarray chip designed for genotyping and large-scale genetic studies. The iScan System is a high-throughput scanner that reads the data generated by the GSA chip. This page provides an overview of the specifications and limitations of the GSA chip and iScan system.
The GSA microarray is made using Illumina’s technology, and it has specific DNA probes embedded onto a chip. These probes are designed to attach only to specific genetic variants. Genotyping with the GSA chip starts with collecting a biological sample, like a buccal swab. DNA is extracted from the sample, amplified with a process called PCR, and marked with some glowing dyes.
The marked DNA is washed over the chip, letting the specific DNA probes attach to the specific DNA probes on the chip. This step is called hybridization. The attached probes are detected using a scanner, like the Illumina iScan, and the glowing signals are measured to determine the genotype of each variant.
The data is analyzed with special software to see if specific variants are present or not. This information can be used for many things, like assessing a person’s risk for diseases, figuring out how they’ll respond to medication, and learning about their genetic ancestry and traits.
The GSA chip is a powerful tool for genetic testing and is used in many areas, such as research, clinical diagnostics, and direct-to-consumer services.
The GSA chip and iScan system are highly accurate and reliable tools for genotyping. The GSA chip has a high call rate (percentage of genotypes that can be accurately called) of over 99% and a reproducibility rate (percentage of genotypes that can be consistently reproduced) of over 99.9%. The iScan system provides accurate and consistent SNP calls across multiple scans.
The GSA chip targets ~700 000 SNPs, which are carefully selected to cover a wide range of human genetic variants. It includes SNPs associated with common diseases, pharmacogenomics, and ancestry information. The chip includes SNPs from diverse populations worldwide, making it suitable for studying genetic variations across different ethnic groups and geographic regions. This global representation is essential for research into the genetic basis of diseases and traits in different populations and has the potential to lead to more personalized and precise medical treatments, as well as ancestry and traits.
limitations
The GSA chip has several limitations:
The chip is not designed to identify all potential variants in a gene; it only tests for pre-determined genetic variants that are commercially defined. This means that other genetic changes that are not included on the chip will not be detected.
The chip can only analyze specific, pre-determined diseases and does not analyze all possible genetic conditions.
The chip does not analyze chromosomal aberrations, such as numerical aberrations (aneuploidies like Down or Turner syndrome) and structural variations (like deletions, duplications, inversions, insertions, translocations and so on), copy number variations (CNVs), mosaicism, chimerism, somatic mutations, or epigenetic changes.
The accuracy of the GSA chip and iScan system depends on the quality of the DNA sample provided. Low-quality, degraded samples result in reduced accuracy.
The GSA chip and iScan system are not diagnostic tools and should not be used to diagnose any medical condition or disease.
accreditations and referent laboratories
All our samples are processed in laboratories with the following accreditations and certifications:
▪ ISO 17025: Accredited analytical excellence.
▪ ISO 13485: Oligonucleotides according to medical devices standard.
▪ GLP: The gold standard to conduct non-clinical safety studies.
▪ GCP: Pharmacogenomic services for clinical studies.
▪ cGMP: Products and testing according to pharma and biotech requirements.