Before the test is conducted
A genetic diagnosis allows:
- A better understanding of the mechanisms of the disease, allowing to anticipate problems and act, whenever possible, in its treatment. The number of genetic diseases with specific treatments are growing, but a correct diagnosis is required to have access to these treatments.
- Genetic counseling, as it permits defining the risk of the disease repeating within the family.
- End of the journey for a diagnosis, leading to the decreased need for complementary tests and optimization of the medical follow-up.
Genome is the entire genetic material in the form of DNA present in each of our cells. The cells use our Genome as a great book which contains a number of recipes, called genes, to elaborate our proteins. The human species has approximately 20 thousand distinct genes. In our great book, which is the genome, only some pages, in fact, bring recipes and the set of such pages is what we call Exome. It’s this part of the genome that contains a great part of the mutations that can cause a genetic disease.
The Exome represents less than 2% of our Genome, however, the great majority of the genetic conditions are caused by mutations occurring in this region. The cost of Exome sequencing is much less expensive and faster than the genome sequencing, as it represents a smaller region, being, thus, a cost-effective manner to investigate rare diseases. In addition, the regions outside the exome are not analyzed due to its difficulty to interpret, since the scientific knowledge concerning such regions is still very limited.
The Gene Panels are composed by selected genes, with a strong relation with a specific group of diseases or with a specific disease. Thus, this is the most cost-effective way when there’s a specific clinical suspicion.
Yes, Exome allows the evaluation of almost all the 20,000 genes known in the international scientific literature, responsible for causing thousands of genetic diseases.
The genomic analysis techniques are recent and subject to periodic adjustments to increase test accuracy. In addition, the clinical meaning of the variants is continuously updated, according to new findings regarding the genes and its effects in our health and diseases. In some cases, the interpretations may change with new scientific discoveries and, therefore, the results must not be addressed as unchangeable. The current genomic analysis techniques cover 95% and 99% of the sequences of interest. It’s possible that an analysis does not indicate the cause of the investigated disease. Upon medical prescription, a new analysis can be conducted by Mendelics, which may charge, at its discretion, for such reanalysis or another analysis not related with the initial question.
Another technical NGS limitation is that it is not optimized to analyze chromosomal structural changes and nucleotide repetition expantions, such as in Huntington’s disease.
To conduct the tests in our laboratory, depending on the test, the sample can be blood or oral mucosa, without differences in terms of quality in the test result.
Blood collection: Fasting or any other type of preparation is not required.
It can be conducted in any laboratory preferred by the patient and the collected sample is stable for three to four days in room temperature.
Oral mucosa collection: It’s necessary to perform the oral hygiene followed by absolute fasting over 30 minutes before the collection (in case of lesions, injuries or mouth ulcers, we do not recommend the collection through oral mucosa due to contamination).
To conduct the test
The following is required to conduct the tests:
- Medical prescription concerning the suspected disease and, preferably, with a summary of the patient’s clinical history. This information is crucial to guide the search for the genetic variants responsible for the clinical picture.
- Signature of a consent term, containing information on:
– Test indications and limitations.
– Risks associated with the test;
– Report content with the result, which will be exclusively directed to answer the medical suspicion.
No, with the Collection Kit, the blood or oral mucosa sample can be collected anywhere and sent to Mendelics’ laboratory, located in São Paulo, Brazil.
The sample must be sent under room temperature, without requiring refrigeration. We recommend that the blood sample is sent as soon as the collection is conducted, due to its stability of approximately 3 to 4 days. The oral mucosa collection may last for up to one month.
Test turnaround time (TAT)
Whole Exome Sequencing: 45 consecutive days
Panels: between 30 and 45 consecutive days (depending on the panel)
Day One – Genomic Newborn Screening: 14 to 28 consecutive days
MLPA: 30, 45 or 75 consecutive days (depending on the gene)
* The expected date is an estimate from the verification of the documentation, pending issues and quality control of the biological sample. In case of next generation sequencing, a complementary analysis can be required through other methods and this will, then, lead to a new TAT estimate.
Click the button RESULTS and select your profile, follow the directions to check the test progress. When the result of your test is available for download, the system will automatically send a warning e-mail.
Due to it being a high complexity test (genetic sequencing) it’s not always possible to advance steps of this process.
The next generation sequencing can be divided into three major steps: laboratory, bioinformatics and medical analysis. In the laboratory step, the DNA is extracted from the sample collected from the patient and the genetic material is sequenced. The sequencing generates such a significant amount of information that computer programs are required to initially address such data. In the bioinformatics step, the entire data generated by the laboratory sequencing, is processed, elaborated and organized, generating a great list of variants present in the DNA region studied in the test. These two steps take from 15 to 20 days to be completed.
In the analysis step, the geneticist physicians will analyze the identified variants and evaluate if there’s something related to the patient’s clinical picture. Once the test reaches the medical analysis step, it can be prioritized. Priority is given to cases where patients are submitted to surgeries or, then, admitted to hospital under severe conditions and the test result may change the medical conduct.
In case of the Whole Exome Sequencing, it’s important to emphasize that, even if the test has been given priority, when the medical analysis step is reached, a complementary analysis can be required. Such need can only be defined by the medical team in the medical analysis step.
The test was completed. What’s next?
All of us have between 25 thousand to 30 thousand variations in our DNA. Most of these variants are neutral or are not related to any disease.
Abracadabra, an artificial intelligence system developed by Mendelics, assists the physicians to analyze the tests filtering the variants with high probability to be associated to the patient’s clinical condition. The analysis will focus in the study of the variants which explain the clinical picture presented by the patient. Thus, most of the variants which are not related to the patient’s clinical condition will not be individually analyzed nor actively sought.
In case the patient or the responsible individual wishes to have access to all the variants identified in his/her test, such data will be fully available in the system, but requires expert professionals to conduct the data analysis.
In some situations, it can be necessary to verify if the DNA variant detected in the patient’s sample was inherited from his/her parents.
For guidance and clarification, we suggest an appointment for genetic counseling.
The genomic analysis techniques are recent and are rapidly evolving. The clinical meaning of the variants is continuously updated with the scientific knowledge advance, therefore, in the future, a negative result can be different.
With the increasing number of individuals investigated by the new genomic sequencing techniques, it’s possible that in the next few years more information allowing to reevaluate the current result appears.
It’s possible that an analysis does not initially indicate a variant as being the cause of the investigated disease. In the case of the Whole Exome Sequencing, if the pathogenic variant is not found, Mendelics’ physicians may carry out a new analysis of the data. Such reanalysis is subsequently conducted and incorporates the most recent scientific advances.
The DNA sample will be used only for the requested test and, then, discarded.
Mendelics commits to store the encrypted digital file for at least five years. The results are confidential and can only be released to other medical professionals or to third-parties upon the patient’s or their legal responsible’s consent.
As Mendelics fundamental policy, the company will not apply for any patents involving the human genes identified by us. Mendelics believes that the human genome is the patrimony of humanity and the access to genetic information is the right of each individual.
