When permanent alteration occurs in the DNA sequence of the gene of the person, the mutation is caused. In such cases, the genetic sequence is completely changed from that of a normal person’s genes. Mutations either affect just a single DNA base pair or completely alter the chromosome segment. Generally, genetic mutations are classified into two different sub-categories –one is the hereditary mutations and the other one is acquired or somatic mutations.
- Hereditary Mutations: In this situation, the alteration in the set of genes is inherited from either of the parents; in rare scenarios from both the parents. These alterations in the genes are passed on from a parent to the offspring through the germ cells and after fertilization; the foetus that is developed continues to grow with the mutated genes.
- Somatic Mutations: Just as the name suggests, a somatic mutation occurs in the somatic cells in the body and not in the germinal cells. This type of mutation is mainly influenced by environmental factors such as ultraviolet radiations of the sun or exposure of the body to any of the nuclear radiations. Somatic mutation can also be the outcome of error in copying of the DNA sequence during the process of cell division.
Different types of genetic disorders:
- Mutation in the single gene inherited from a parent: Mutation caused in single-gene inherited from the parents is often referred to as monogenetic disorder. The diseases classified under this category are:
- Sickle-cell anaemia
- Cystic fibrosis
- Huntington’s disease
- Marfan Syndrome
- Multiple Gene Inheritance: When genetic mutations are caused due to multiple factors affected either by genetic inheritance or environmental factors; such condition is referred to as multiple gene inheritance. The chronic diseases that are caused due to such conditions are:
- High Blood Pressure
- Heart Disease
- Genetic disabilities due to chromosomes: Chromosomes are the careers of genetic materials and any slight change in their number or structure can result in mutation. This type of mutation occurs only and only during cell division. Some of the abnormalities caused due to chromosomal mutations are:
- Klinefelter’s disease –having 47 chromosomes instead of 46. In this syndrome, there is an extra pair of the X chromosome.
Turner’s syndrome –in this situation there is only 45 chromosomes instead of 46. The Y chromosome is missing.