A genetic disorder is an illness which is caused by discrepancy in an individual DNA. These discrepancy ranges from simple mutation of an individual gene to decrease or increase in the whole chromosome or various chromosomes. All these types of genetic disorders may or may not be descended.
In most cases, genetic disorders are rare and affect a few people out of a million. With all available information about the genetic disorders, this results to classification of these disorders into four broad categories. These four types of genetic disorders and are discussed below.
A Single Gene Disorder
It is also referred to as monogenic or mendelian disorder. These types of genetic disorders are evident when there is an abnormality in a single gene of a chromosome. Studies suggest that more than 4000 human diseases are as a result of a single gene mutation. It has high possibilities of being passed down in line from parents to children. These disorders are:
These are those that arise due to the abnormal gene donated from one parent that is, achondroplasia.
These types of genetic disorders caused by the abnormal genes contributed from both parents, for example, sickle cell anemia and cystic fibrosis.
It is caused due to the single abnormal gene that is on the X chromosome. Hemophilia is a best example of a disorder result by this type of discrepancy. X-linked dominant affect both the female and the male persons, while the X-linked recessive affects men more than women.
This is the single gene disorder caused by discrepancy on the Y chromosomes. Since only the male possesses this chromosome, it is only them who suffer from this condition or inherit this disorder. One good example is the male infertility which is only evident in men.
It is also referred to a maternal inheritance as it relates to the mitochondria DNA. Because the woman egg is the only one that contributes mitochondria for the development of the embryo, then mothers are the only ones who can descend this disorder. One example for a disease due to this disorder is Leber’s Hereditary optic neuropathy. The alteration of mitochondrial DNA is the major cause of this disorder.
These types of genetic disorder are as a result of various factors such as lifestyle and environment. The multifactorial disorders that associated with lifestyle includes: diabetes obesity, heart diseases, hypertension etc. The multifactorial disorders that are contributed by environmental factors are asthma, cancer, autism, cleft palate, autoimmune disease etc.
The mutations that occur to the chromosomes, usually leads to alteration of different genetic information. This leads to chromosomal disorder such as Trisomy 21 or Down syndrome. Here, a person possesses three same copies of chromosome 21.
The other examples of chromosomal abnormalities are: William’s syndrome, Klinefelter syndrome, Turner syndrome etc.
Nevertheless, there are specialists to be consulted about various types of genetic disorders who’re the genetic counselors. Through having a surveying the family history and pedigree, they are able to use these to determine risks associated with certain disorders. They also offer counseling to parents and the various methods of treating and preventing these disorders.