DNA repair

The process by which the cell identifies and repairs the damages done to the DNA molecules is known as DNA repair. DNA damage can be caused due to normal metabolic activities or environmental factors like Radiations or Ultra-Violet light. This results in the molecular lesions as many as 1 million per day. There is a high possibility that the lesions cause structural damage to the DNA molecule and they can also modify or eliminate totally the ability of cell to transcribe the gene that affected the encodes of DNA.

Several other lesions are harmful for the mutation of the genome of cell and this affects the survival of its daughter cell after undergoing the process of mitosis. The process of DNA repair is carried out constantly as it responds continuously to the damage in structure of DNA.

Extra cellular environment, age of cell, type of cell are some of the factors on which rate of DNA repair is dependent. Any cell which has a large amount of DNA damage or it can no longer be effectively repaired, such cell enter the following 3 stages

• Senescence, which is stage of dormancy and it is irreversible
• programmed cell death, apoptosis which is also known as cell suside
• unregulated division of cell which finally leads to serious health problems like cancer and tumor

The DNA repair ability is very important to integirty of the genome of the cell. It is very essential that the DNA repairing fuction is carried out smoothly for the normal functioning of that organism.

Gene therapy

Genes are carried on the chromosomes and they are the basic functional and physical units of hereditary. Genes provide the guidance for specific sequences of the basis which encodes instructions of making proteins. Even thought gene get vital attention the key role is played by the proteins, which perform most of the life functions and is also responsible for number of cellular structures. But in case if the genes are altered, proteins cannot perform their normal functions and may result in genetic disorders.

Gene therapy provides various ways and means for fixing the genetic disorders or defects. There are number of approaches which can be used by Gene therapy. Depending upon the type of disorder the most suitable approach is adopted generally. Following are some of the common approaches adopted by the research teams:

An insertion of the normal gene is done in the non specific location within genome to replace the non functional gene.

The normal gene can be replaced in place of some abnormal gene via the homologous recombination

With the help of reverse mutation, the abnormal or the defective gene can be repaired by which it can return to its normal gene functions.

There can be modification done in the regulation of the particular gene.

Multifactorial Disorders

It is studied by researchers that a genetic component is responsible for most of the diseases and conditions in human beings. Some disorders like the cystic fibrosis or the sickle cell anemia are a result of mutations in a single gene. However, the cause of many other diseased conditions is very complex. Some of the common disorders like diabetes, heart disease and obesity are not a result of a single genetic cause, but they are caused due to the result of multiple genes, in combination with the environmental factors as well as the lifestyle of the person. Multifactorial Disorder is caused by the interaction of genetic and non-genetic factors along with the environmental factors.

Multifactorial Disorders are frequently seen clustering in families, but they do no have a well-established pattern of inheritance. Thus, it becomes difficult to determine whether a person is at risk to inherit or pass on this disorder to the next generation. Multifactorial Disorders are very complex, hence difficult to treat as well as study as the particular factor responsible for most of these disorders are not yet identified.

There are many common diseases seen running in the family, but the simple inheritance pattern of a single gene disorder is seen lacking there. These Multifactorial Disorders includes diseases like epilepsy, manic depression, asthma, schizophrenia and hypertension. Some of the developmental abnormalities also come under this category like the cleft palate, neural tube defects like spina bifida and congenital heart defects.

The Multifactorial Disorders have a very low heritability in comparison with the single gene disorder. For instance: only 5-7% of your close relatives or family members of diabetics suffer from the same disease, and lower would be the case for single gene disorder such as cystic fibrosis. This clearly states that a single genetic factor is never responsible to cause diseased conditions in your body. There are a number of genes that combine along with the environmental factors like exposure to hazardous chemicals or poor diets, which cause disorders in a person.

The occurrence of the Multifactorial Disorders is thought to be dependent on the balance of risks. There exists a balance between the variants of genes with positive as well as negative effects, and between environmental factors again with positive as well as negative effects. Too many negative factors, both environmental and genetic may tilt the balance towards various disorders.

In a Multifactorial Disorder, sometimes the risk may depend on the sex of the affected person. For instance, pyloric stenosis is a Multifactorial Disorder occurring five times more often in males as compared to females. If a female suffers from pyloric stenosis, her as well as her parent's risk of having other child affected with this condition will be higher than if a male child would be suffering with it. The occurrence of this condition in females has a higher genetic liability apparently, a number of abnormal genes are isolating in the family.

Thus, we can shortly state that there is a similar risk for the first-degree relatives such as parents, siblings or offspring's to develop Multifactorial Disorder. The severity of the disorder and the sex of the person can play a role in modifying the risk. Some of the common chronic diseases are Multifactorial Disorders of the genes. The conditions with Multifactorial Disorder include cancer, birth defects, coronary artery diseases and mental disorders.