Genetic diseases are disorders associated with irregularities in the construction of genes. Genes are the building blocks of heredity and are passed from parent to child. DNA is the instruction of protein production in the body that perform most of the tasks in cells. Moving particles are building structures smash toxins and perform various maintenance activities.
Sometimes there are certain mutations, changes in the gene or genes that affect the instructions for protein production, and thus may not work correctly or cease to function altogether. The whole thing can all lead to genetic diseases.
Mutation of genes can be inherited from one or both parents, and there are also changes in the genes “acquired” during life.
There are three types of genetic defects:
Monogenic disorders – where the mutation involves a single gene, as exemplified by sickle cell anemia.
Chromosomal abnormalities – in which chromosomes (or parts thereof) contain gaps or are amended. Chromosomes are the structures that hold our genes, and an example of a chromosomal disorder is Down syndrome.
Complex disorders in which mutations exist in two or more genes. Often a significant impact on these diseases has a style of life and the environment. Example conditions of the compound is a tumor of the colon.
This type of genetic diseases is caused by mutations in mitochondrial DNA. Mitochondria are small, round or rod-shaped organelles that are involved in the process of cellular respiration. Each mitochondrion may contain from 5 to 10 circular pieces of DNA. Because the ova (but not sperm cells) transmit their mitochondria during fertilization, mitochondrial DNA is always inherited from the female parent.
An example of genetic mitochondrial diseases are:
- an eye disease called hereditary optic nerve atrophy Laber,
- type of epilepsy called MERRF- syndrome myoclonic epilepsy with ragged red fibers
- a form of dementia melasma.
The chromosomes of various designs consisting of DNA and protein that are found in the nucleus of each cell. The chromosomes are carriers of genetic material, so abnormal chromosome or its particular structure can cause genetic disease. Abnormalities in chromosomes usually occur due to problems with cell division.
An example here is Down syndrome (trisomy 21) common disorder in which the patient has three copies of chromosome 21.
Multifactorial inheritance, which is called complex or polygenic is caused by a combination of environmental factors and mutations in different genes. For example, the susceptibility of it was found chromosomes 6, 11, 13, 14, 15, 17 and 22, at the actions causing cancer. Some chronic diseases have their source is in multifactorial disorders.
An example of them are:
- heart diseases,
- high blood pressure,
- Alzheimer’s disease,
Multifactorial inheritance is also related to inheritance features, such as fingerprint patterns, height, eye color and skin color.
The human genome is a treasure trove of human inheritance. 46 human chromosomes can accommodate nearly three billion pairs of DNA which contain about 20,500 protein-coding genes. Coding regions are less than 5% of the genome, and some chromosomes have a higher density than other genes.
The majority of genetic diseases caused by a direct result of a mutation in one gene. However, one of the most difficult problems to solve puzzles, how genes contribute to diseases that have a complex pattern of inheritance, as in cases of diabetes, asthma, cancer or mental illness. In all cases, you can not determine whether a person’s illness develops or not. It is possible that for the existence of the disease, is needed more than one mutation, and some genes may have subtle effects on susceptibility to a disease. Genes may also have an impact on how a person responds to environmental factors.