The application of genetics in medicine began in the early twentieth century with the understanding of Garrod and the other doctors that the laws of inheritance Mendel can explain the re-emergence of some diseases in families. Over the next 100 years, medical genetics has grown from a small section engaged in several rare hereditary diseases, to recognized medical specialty, concepts and methods which are important components of diagnosis and treatment of many diseases both frequent and rare.
Moreover, in the beginning of the XXI century completed the project “human Genome” is an international study aiming to determine the full content of the human genome as the sum of the genetic information of our species (the suffix-OTE in Greek means “all” or “full”). Now we can explore the human genome as a single solid object, rather than one gene at a time. Medical genetics has become part of the broader field of genomic medicine, conducting large-scale analysis of the human genome, including gene expression, study of variability of human genes and interaction of genes with the environment, with the aim of expanding the possibilities of medicine.
Medical genetics focuses not only on the patient but on the entire family. Comprehensive family history is an important first step for the analysis of any disease, regardless of genetic or not. As pointed out by childs, “to clarify the family history is bad practice”. Family history is important because it can be determinant in the diagnosis, it can indicate that the disease is hereditary, can tell about the natural history of the disease and the changes in its course finally, it can help determine the type of inheritance.
In addition, the family awareness component in the disease allows to evaluate the risk to other family members in need of screening or prevention, and the patient and his family may be offered genetic counselling.
Over the past few years, the project “human Genome” has made available the complete sequence of the entire deoxyribonucleic acid (DNA) of a person, the knowledge of which allows to identify all human genes, to determine the degree of their variability in different populations and in the end to understand how changes in these genes contribute to health or disease.
- Genetics is fast becoming the Central organizational element in medical practice. Here are just a few examples of the vast array of applications of genetics and genomics in medicine today.
- A child with multiple congenital malformations and normal conventional chromosome analysis, genomic test runs with high resolution to exclude submicroscopic chromosomal deletions or partial trisomy.
- A young woman with a family history of breast cancer receives targeted training, interpretation of the examinations and the support of a consultant specializing in hereditary breast cancer.
- Obstetrician-gynecologist sends samples of chorionic villi taken from the 38-year-old pregnant woman in the cytogenetics laboratory for examination to exclude abnormalities in the number or structure of chromosomes of the fetus.
- Hematologist unites family and medical history with the study of genes of a young man with deep venous thrombosis (GW) to assess the benefits and risks of the introduction of anticoagulant therapy.
- In Oncology, the use microcephaly analysis of gene expression of the tumor to determine prognosis and choice of treatment. • The oncologist is testing patients for the presence of genetic variants that can predict a good response or adverse reaction to a chemotherapy drug.
- A forensic pathologist uses a database of genetic polymorphisms in the analysis of DNA samples obtained from remains of victims and their relatives to identify the dead (e.g. 11 September 2001 in the attack on the world trade Center in new York).
- The discovery of signaling pathways of carcinogenesis, activated somatic mutation, led to the development of a powerful specific inhibitor of the path which is successfully used in the treatment of cancer. Genetic principles and approaches are not confined to one medical specialty or subspecialty, and penetrate into different areas of medicine.