Genetic Testing

Classification

Diagnostic tests
They allow to decide a diagnosis or confirm a clinical suspect of an ill person. They can be performed during the prenatal period or during the whole post-natal period. Examples: the cytogenetic analysis to identify chromosome anomalies, the search of mutations in the CFTR gene in newborns with recurrent pulmonary infections and suspected cystic fibrosis, the identification of expansion of the FRAXA gene in patients with a mental retardation diagnosis.

Pre-clinic and pre-symptomatic tests
Several genetic diseases, especially the autosomal-dominant type, can come out afterwards. If the responsible gene is known it is possible to determine if a subject without symptoms inherited or not the mutated allele thus developing the related disease. The the genetic test result can be an opportunity to lower the mortality of the disease, prevention and adequate therapies treatments are available. However, to perform a genetic test doesn’t often imply a better clinical management of the disease, even if detecting risk subjects can be important to apply adequate preventive strategies.

Tests to evaluate genetic genetic susceptibility
Some tests allow to detect genotypes which do not directly cause the disease, but can increase the risk of developing it, if they are associated to environmental factors. Examples of these conditions are the glucose-6-phosphate dehydrogenases deficit, which predispose to acute hemolysis crisis after treatment with some drugs, or the alpha-1-antitripsine deficit, that, if smoking associated, predispose to juvenile pulmonary emphysema.

Tests to detect heterozygotes[/br]In case of autosomic recessive diseases, such as thalassemia, it is possible to detect the heterozygote carrier in the population. This research allowed to reduce the disease incidence when correctly carried on.

Medical-legal research
The presence in the human genome of highly polymorphic regions, that is individually variable, and markers useful to distinguish these regions with simple variables, allows very likely to assess paternity and biological traces of individuals.