Biochemical and genetic test methods

Our dedicated team ensures the highest quality standards applied for each analysis and for results you can rely on

Our genetic expertise and state-of-the-art testing methodology is at the heart of the services we provide.

 

 

  1. Genetic Test Methods

Biochemical and genetic testing methods and workflows

CENTOGENE´s in-depth medical expertise is supported by the application of cutting-edge technologies. We utilize almost all of the existing testing methods in our workflows, processing every sample in-house. We adhere for each testing method to the highest international standards (CAP, CLIA, ISO) for establishment and validation.

Genetic and biochemical testing methods at CENTOGENE

Sanger sequencing

The term DNA sequencing refers to methods for determining the order of the nucleotide bases adenine, guanine, cytosine and thymine – in a molecule of DNA using a capillary sequencer.

Hotspot analysis:

Investigates mutations that show an increased frequency in the population. There are different hotspot mutations based on the ethnicity/ancestry of each patient (as provided by physician).

Full gene sequencing:

Analysis of the entire protein-coding regions of a gene (associated with a specific disorder ) including exon-intron boundaries.


Fragment length analysis

Some diseases are caused by insertions/deletions which cannot be detected via classical Sanger sequencing. Moreover, in some genes, there are repeats of nucleotide motives CAG. The size of the repeat regions consisting of e.g. CAGs varies between individuals and is polymorphic in normal individuals. However, when the number of repeats exceeds a certain threshold, neurological symptoms may be caused (pathological repeat expansion). In these cases, fragment length analysis (FLA) and/or repeat primed assays are utilized to detect the extent of the expanded repeats using a capillary sequencer.

Downloads for biochemical and genetic testing methods

  • Request form - Whole genetic test portfolio

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Deletion/duplication testing

It identifies large deletions or duplications using MLPA, qPCR or ddPCR.

MPLA:

MLPA (multiplex ligation-dependent probe amplification) is a semiquantitative multiplex PCR method detecting abnormal copy numbers of up to 50 different genomic DNA or RNA sequences, which is able to distinguish sequences differing in only one nucleotide. Probes bind to the DNA, are ligated and amplified by PCR. Results are obtained using a capillary sequencer.

Although for most hereditary conditions (partial) gene deletions or duplications account for less than 10% of all disease-causing mutations, for many other disorders this is 10 to 30 % or even still higher. The inclusion of MLPA in clinical settings can therefore significantly increase the detection rate of many genetic disorders.

qPCR:

The polymerase chain reaction (PCR) is one of the most powerful technologies in molecular biology. Using PCR, specific sequences within a DNA template can be copied, or “amplified,” many thousand-fold to a million-fold using sequence-specific oligonucleotides, heat-stable DNA polymerase, and thermal cycling. In real-time PCR (qPCR), the amount of DNA is measured after each cycle via fluorescent dyes that yield increasing fluorescent signals in direct proportion to the number of PCR product molecules (amplicons) generated. Data collected in the exponential phase of the reaction yield quantitative information on the starting quantity of the amplification target.

ddPCR:

In digital droplet PCR (ddPCR) is somewhat similar to a qPCR approach, however a water oil emulsion technique is used to divide the PCR solution into smaller reactions. The sample is partitioned into nanoliter-size samples and encapsulated into oil droplets. In every droplet, the amplification process (40 cycles) takes place independently. Only in droplets containing the target DNA sequence can amplification occur resulting in a fluorescent signal based on probes or DNA intercalating dye. Thus, there are only two possibilities: “positive/negative” –> digital: “on/off.” The number of positive droplets correlates to the starting amount of DNA thus allowing for absolute quantification.

Latest scientific articles - Deletion/duplication testing

  • CentoWebinar - A journey to the future: Whole genome sequencing for the diagnosis of heterogeneous genetic disorders

    Last year CENTOGENE announced its new sequencing facility for rare hereditary disorders, which uses Illumina’s HiSeq X® sequencer. Now, some months after our journey started, our CSO Prof. Peter Bauer will explain CENTOGENE’s experience using this groundbreaking next generation sequencing (NGS) technology for the clinical diagnosis, give some insights in whole genome sequencing and show interesting clinical cases.

  • Clinical exome sequencing - Results from 2819 samples reflecting 1000 families

    A study was conducted using whole exome sequencing (WES) to identify underlying pathogenic variants, or likely pathogenic variants, in 1,000 diagnostic cases from 54 different countries. Patients selected displayed a wide variety in the number, nature and severity of symptoms. Clinical information given by the requesting physicians was translated to HPO terms and WES was performed on patient samples according to standardized settings.

  • Guidelines for diagnostic next-generation sequencing

    The work was performed by a group of laboratory geneticists and bioinformaticians, and discussed with clinical geneticists, industry and patients’ representatives, and other stakeholders in the field of human genetics. The statements that were written during the elaboration of the guidelines are presented here.

Biochemical/biomarker analysis

Enzyme assay:

Measurement of enzyme activities for lysosomal storage disorders (LSDs): enzymes extracted from dried blood spots (DBS) or leucocytes convert artificial substrates into products which can be quantified using tandem mass spectrometry or via fluorimetric/spectrophotometric methods.

Biomarker analysis:

Measurement of biomarker concentrations in dried blood spots via tandem mass spectrometry.

Latest scientific articles - Biomarker and biochemical analysis

Next generation sequencing

Next generation sequencing (NGS) enables us to generate a large amount of sequencing data in a massively parallel manner (millions of sequencing reactions at the same time). This makes sequencing much faster and much more cost-effective, and thus allows us to sequence large panels, whole exomes (WES) and even whole human genomes (WGS).

Whole exome sequencing

Identifies the molecular basis of a genetic disorder in an affected person by analyzing the total number of exons (= exome), the complete protein-coding region of the genome. These regions make up in total approx. 1% of the genome.

Whole genome sequencing

Reveals comprehensive information about the genetic composition of an individual by exhaustively covering the whole genome, thus both protein-coding and non-coding regions.

Latest scientific articles - Next generation sequencing

  • CentoWebinar - A journey to the future: Whole genome sequencing for the diagnosis of heterogeneous genetic disorders

    Last year CENTOGENE announced its new sequencing facility for rare hereditary disorders, which uses Illumina’s HiSeq X® sequencer. Now, some months after our journey started, our CSO Prof. Peter Bauer will explain CENTOGENE’s experience using this groundbreaking next generation sequencing (NGS) technology for the clinical diagnosis, give some insights in whole genome sequencing and show interesting clinical cases.

  • Clinical exome sequencing - Results from 2819 samples reflecting 1000 families

    A study was conducted using whole exome sequencing (WES) to identify underlying pathogenic variants, or likely pathogenic variants, in 1,000 diagnostic cases from 54 different countries. Patients selected displayed a wide variety in the number, nature and severity of symptoms. Clinical information given by the requesting physicians was translated to HPO terms and WES was performed on patient samples according to standardized settings.

  • Guidelines for diagnostic next-generation sequencing

    The work was performed by a group of laboratory geneticists and bioinformaticians, and discussed with clinical geneticists, industry and patients’ representatives, and other stakeholders in the field of human genetics. The statements that were written during the elaboration of the guidelines are presented here.

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