Biotechnology proposes a major avenue to developed therapies and treatments. The development and usage of biotechnology techniques have enabled us to define the structure of DNA as well as the coded message hidden in the gene of DNA. Evidently, the sequence of genes stretched on an organism’s DNA is accountable for the individual traits.
It has been discovered that faulty genes cause few diseases of the human body viz. Huntington’s disease, a degenerative disorder of nerve cells. A single gene that produces a defective protein results in nerve cell death.
The known genes for causing specific diseases can be used as targets to develop designed treatments for those diseases. Since the genes causing the disease is known, the finding of the treatment becomes cheaper and easier. The conventional pharmaceuticals are not able to reach these gene targets.
Another major reason is the large biological molecules like synthetic insulin for which biotechnology is being used. It cannot be manufactured in a traditional chemistry laboratory. Synthetic insulin can only be synthesized by living cells using biotechnological techniques. There are other large molecules also, produced by the means of biotechnology. For example, blood clotting factors for haemophiliacs, human growth hormone, fertility drugs etc.
Biotechnology has a vital role to play in present diagnostic sciences. The modern knowledge of DNA and its genes can examine the DNA of a person for following aspects:
· Prenatal diagnostic screening for diseases viz. Down syndrome
· Determination of the sex of an unborn baby
· Screening of newborns for HIV, phenylketonuria
· Screening of carriers: the unaffected individuals are identified for carrying one copy of a gene for a disease, which actually requires two copies of a gene to produce the symptom, for example haemophilia and Tay Sachs disease
· Estimation of the risk for development of adult-onset cancers by presymptomatic testing: for example bladder cancer and colon cancer). A mutation in the BRCA1 gene in a person has a high risk of developing breast cancer
· Prediction of adult onset disorders by presymptomatic testing: for familial high blood cholesterol
· Confirmation of the disease in symptomatic individuals: for example Huntington’s disease and cystic fibrosis
· Forensic testing: analysis of blood, semen, hairs for prosecutionof offenders, paternity testing.
For diagnostic DNA testing, two techniques are generally used. The first technique involves comparing the sequence of bases in the gene of the patient to that of a healthy individual and in the second technique short pieces of DNA i.e. probes are used that consist sequences complementary to suspected mutations. These probes search for the complementary sequences among the patient’s DNA, then bind to it and flag or mark it.
Biotechnology helps in the development of treatments to cure diseases in mainly two ways: gene therapy and pharmacogenomics.
Gene therapy can treat diseases by changing the genetic information of cells. Even though, gene therapy is new aspect, cases are there when patients have been cured by this technique.
Gene therapy mostly follows one of these approaches:
· the substitution of a mutated gene with a normal gene
· the knocking out the activation of the mutated gene
· Insertion of a completely new gene into the cells.
At present, somatic gene therapy is performed on body cells. In this therapy, changes in genetic information’s are not passed on to the offspring’s. By contrast, in Germline therapy, the reproductive cells (sperm and ova) are involved and any changes in genetic information’s will be transferred on to the progenies. This type of gene therapy is still in its infancy and is not being experimented on patients.
In somatic gene therapy, the vector virus delivering the gene of interest is introduced into the patient intravenously. Consequently, new gene is delivered into the cell as the vector infects the target cells.
In 1990, the first case of gene therapy was performed by doctors at the National Institutes of Health (USA) for treating a toddler girl suffering from SCID (severe combined immune deficiency). SCID is caused due to mutation in ADA gene, which regulates the formation of an enzyme, adenosine deaminase. The medical practitioners took out bone marrow cells from the girl and treated it with a vector inserted with a normal ADA gene; and then re-introduced the treated bone marrow cells into the girl. The treatment made her immune system to start functioning normally.
Gene therapy is also being explored by scientists to treat cancer cells. Several possibilities like replacing altered or missing genes causing cancer or introduction of new genes into cancer cells are being experimented to make them more susceptible to treatment.
Pharmacogenomics would help the doctors to recommend the correct medication and dosage on the basis of patient’s genetic profile, thereby minimizing the risk of undesirable reactions, over dosage and side effects. Identification of SNPs is the basis of pharmacogenomics. Earlier, the sequencing of a genome was an expensive and lengthy procedure, but with the improvement of the DNA microarray, the sequencing has become easier and quicker. SNPs are being used to map and recognize specific genes that lead to the development of diseases such as cancer, arthritis and diabetes. The proteins produced by these genes become targets for novel therapies.
Pharmacogenomics play a significant part in treatment of blood cholesterol levels, oncology, and treatment for patients with cardiovascular diseases, tailoring treatment for patients with psychiatric disorders.
Nevertheless, Pharmacogenomics is still in its infancy to individualise treatment procedures. Pharmacogenomic testing to decide a patient’s potential reaction against a treatment is sophisticated and advanced in only few countries.
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