Information for patients: Genetic testing
Catlab's Genetics department has produced an informative note aimed at patients, which briefly but clearly explains what a genetic study consists of, which sample is suitable and which methods currently exist.
Likewise, patients will also find information related to result interpretation and the advantages of carrying out these studies.
Hexanucleotide expansion in C9orf72 gene, associated with frontotemporal dementia and amyotrophic lateral sclerosis
Frontotemporal Dementia (FTD) is considered one of the most common forms of dementia in the population under the age of 65, with a prevalence of 10 cases per 100,000. Patients with DFT suffer a degeneration of the neurons in the frontal and temporal lobes that leads to changes in behavior and personality, deficits in executive functions and language deficiencies. The expansion of the C9orf72 gene is considered the most common hereditary genetic cause for both diseases. This article describes the study for this expansion at Catlab.
GENETICS - Array CGH in neurodevelopmental pathologies
The prevalence of neurodevelopmental pathologies in the general population is estimated at 1-3%. Genetic testing allows a more accurate prognosis. Today, conventional chromosomal analysis has been replaced by array comparative genomic hybridization (aCGH) techniques. At Catlab, since 2014 studies with the aCGH technique have been carried out, achieving good diagnostic performance. The good results are the product of the close relationship with the clinicians, the joint work in the diagnostic orientation, and the approach to be followed in each case, with the added value of the orientation towards the family counseling.
GENETICS - Pharmacogenetic study of the variants of the DPYD Gene in cancer patients
Fluoropyrimidines are anticancer compounds that act as antimetabolites in chemotherapies of different tumors. Its administration has to be controlled very well, since an excess of metabolites can trigger toxicity. The elimination of these metabolites is mainly controlled by the activity of the DPD enzyme. The DPYD gene encodes the DPD enzyme. It is a highly polymorphic gene, and the detection of the variants allows to predict the enzymatic activity before starting the treatment, thus preventing the adverse effects of DPD deficiency. Thus, based on the variants found, a calculation is made of the patient's ability to metabolize fluoropyrimidines. With this, we can categorize the patients according to the metabolization capacity, and the standard drug dose can be corrected and personalized.
GENETICS - Study of rearrangements in microsatellite instability of tumor DNA
The mismatch repair system (MMR) repairs small sequence errors, produced in DNA replication. Certain tumor subtypes present as a trigger mechanism a defect in the MMR genes, which gives them a biological behavior and a different prognosis to other tumors of the same tissues. This defect manifests itself at the molecular level as an instability in the size of gene regions called microsatellites. In Catlab, the analysis of five microsatellite regions is performed, using PCR and capillary electrophoresis on paraffin samples of tumor tissue, as a marker of MMR system deficiency.
EXTRA-ANALYTIC - Screening of aneuploidies in maternal blood
This November, the new Pregnancy Protocol was launched, which includes the screening of aneuploidy in maternal blood. It allows DNA detection of the fetus in the mother's blood from week 12, for women, in which biochemical screening is high risk and intermediate risk. Screening consists in the detection of numerical anomalies of chromosomes 13,18 and 21. That is, detection of Down Syndrome (Trisomy 21), Edwards Syndrome (Trisomy 18) and Patau Syndrome (Trisomy 13).
GENETICS - Molecular markers in glioma
Glioma is the most common primary tumor among intracranial malignancies. There is a growing number of biomarkers in glioma in the field of research, but currently in routine three are used: Codeletion 1p / 19q; IDH 1/2 mutation; and Methylation of MGMT.
GENETICS - TCR Clonality
The T cell receptor (TCR) is a membrane receptor, present in mature T lymphocytes (LT), constituted by two different transmembrane polypeptide chains. The αβ T lymphocytes constitute around 95% of the total circulating T lymphocytes in peripheral blood, and are the best characterized in terms of their biology and functions. Its TCR is a heterodimer consisting of an α and a β chain. The genes that code for each of the chains of the TCR, are formed by a set of different segments that, during the maturation of the LT, unite in a random and irreversible way, through a directed process of somatic recombination of the DNA. The study of the gene rearrangements of the genes encoding the TCR is a marker of clonality and, therefore, of malignancy, ideal in the diagnosis and monitoring of lineage PFS.
CYTOGENETICS - Mutations in the FLT3 Gene and Acute Myeloid Leukemia (AML) strong>
The FLT 3 receptor is found in the normal hematopoietic precursors of Bone marrow, and plays a key role in cell proliferation and survival. The gene encoding the FLT3 protein is located on chromosome 13 q12, and mutations in this gene occur with a high frequency in AML patients. The most frequent mutation is internal tandem duplication (FLT3-ITD). The most common mutation is internal tandem duplication (FLT3-ITD). This mutation is a poor prognostic factor in AML, and is associated with clinical progression and relapse.
CYTOGENETICS - Genetic markers in the myeloproliferative syndromes classification
Myeloproliferative neoplasms (NMP) are clonal disorders of hematopoietic precursor cells, characterized by the proliferation of myeloid or more lines. Classically, the NMP were subdivided according to whether the Philadelphia chromosome (BCR / ABL1), confirming a chronic myeloid leukemia (CML), or if the patient was BCR / ABL1 negative, was detected using clinical criteria. Currently, the study of mutational status of JAK2, MPL and CALR genes, plays an important role in the classification of different subtypes of NMP.
CYTOGENETICS - Array-CGH
Array-CGH technology detects dose changes (copy number changes or CNV), along the whole genome. The technique is based on the competitive hybridization between a reference DNA and a patient DNA.
CYTOGENETICS - New method of noninvasive prenatal screening. Study of fetal aneuploidy in maternal blood
Based on the study of circulating fetal DNA in maternal blood, new techniques have been developed for prenatal aneuploidy screening with high sensitivity and specificity.
CYTOGENETICS - Document of informed consent for genetic testing
For testing oriented genetic diagnosis, is necessary and required that patients know the implications of these tests before implementation, and the best guarantee that this process will be appropriate is the informed consent document.
CYTOGENETICS–Cytogenetic study of byproducts of miscarriage. Approximately 10-15% of clinically recognized pregnancies end in miscarriage, the majority of which are produced in the first trimester, and 50% of these are associated with chromosomal anomalies.
CYTOGENETIC - Y chromosome microdeletions
Infertility is a problem that affects 10-20% of couples. In some cases, the cause is microdeletions in the distal portion of chromosome Y.
Cytogenetics - Quantification of BCR-ABL reorganitation
There are some recurring cytogenetic abnormalities hematologic malignant diseases, and the first to be described was the translocation t (9; 22) (q34, q11