Genetic testing for mutations in the genes responsible for human disease tests. The nucleotide sequence of the genes and the amino acid sequence of the protein encoded by the genes responsible for diseases
The constitution and the normal function of the human organism, depend on a genetic basis, that is, DNA that is present in our chromosomes. The chromosomal DNA is structured genes, corresponding to the DNA sequences to be expressed together to perform a specific function. The genes that form the DNA of the chromosomes are formed by nucleotide sequences of adenine, guanine, cytosine and thymine. Genetic tests try to determine whether the nucleotide sequence of the genes are altered, ie, nucleotides have been changed. If the nucleotides of a gene change, the protein may have one or more different amino acids, and therefore its structure and function will not be the same as that of the normal protein.
Thus, genetic testing, although they studied the nucleotide sequence of genes, detect whether the amino acids encoded by the nucleotide sequence found is the same normal protein, or a modified protein.
Investigated mutations in genetic testing, may correspond to germline mutations or somatic mutations. Germline mutations are those that are inherited from the parents, ie being present in the chromosomes of the father and / or mother are transmitted to offspring via the chromosomes that are in the sperm and ovum. These mutations can be detected in any nucleated cell in the body, because in all there is a specific set of genes (2n = 46 chromosomes: 22 pairs of non - sex chromosomes -autosomas- and a pair of sex chromosomes -XX [women] or XY [male] -). These germline mutations may be autosomal dominant or autosomal recessive. The first, autosomal dominant, are its presence in one of the alleles of the non - sex chromosomes received from either parent involves the manifestation of the disturbance (illness). Conversely, autosomal recessive, requiring that the mutation is present in both alleles from the father's and from the mother, so that the alteration is manifested. It is sometimes said that the inheritance of the disease is X - linked, because the mutated genes are present on the X chromosome (not autosomal).
There are other mutations that unlike germline mutations are not present in all cells of an organism, but only some of them. These mutations are called somatic mutations that are genetic alterations that occur during the development and are present in a tissue or organ. These mutations can also be known through genetic testing, but is required to have those samples affected tissues.
Genetic testing in Valencia Institute of Microbiology (IVAMI) are based amplification PCR methods (Polymerase Chain Reaction) of each of the exons of a gene encoding a protein. An exon, is nothing more than each of the units of expression of a gene, ie each of the amino acid sequences will be a protein. There are proteins that are composed of sequences expressed through an exon or exons few, but nevertheless, there are others that are made up of amino acid sequences expressed from many exons. Therefore, the difficulty for the study of mutations present in a protein, and therefore in the genes that encode depend on the number of exons, and each requires a PCR reaction, and at least one sequencing reaction to determine the nucleotides present. Sometimes proceeds to perform a test of quantitative PCR (qPCR) to know the length of a gene where the mutation does not correspond to a change in nucleotide sequence of a gene, but the loss of part (deletion) , or increased insertion (insertions).
Exist in our catalog of genetic testing more than 1,000 genetic diseases that we can study through genetic testing, detecting mutations in genes that have been known that are involved in them. This ratio increases as scientific studies are discovered that cause diseases or syndromes genetic alterations.
However, if an illness that was of interest was not in our catalog ( www.ivami.com ), you can notify us and we would develop the evidence needed.