Types of Genetic Disorders

'It's in my genes'. This is one of the most common phrases we tend to use in our daily lives. Genes are DNA segments that are carried in chromosomes. These genes help in determination and expression of different human characteristics. These characteristics include hair color, height, weight, etc. These genes even play a role in your personality expression and behavior patterns. The most important aspect of genes is that they also have the ability to pass on diseases and disorders from the parent to the progeny. This brings us to the focal point of this article. What are the different types of genetic disorders? Let us first understand, what is a genetic disorder, before moving on to the human genetic disorder types.

What are Genetic Disorders?
The diseases or illness that arise due to abnormalities or discrepancy in genes or chromosomes are known as genetic disorders. DNA is the basic unit of life and genes make up DNA. Any abnormalities within genes, changes the expression of the gene. This change may lead to different genetic disorders. Sometimes, diseases or disorders are expressed due to two recessive genes coming together. Another factor that leads to genetic disorders are environmental factors, like exposure to radiation. There are many rare genetic diseases and disorders that are seen in one person in every thousands or maybe million individuals. Let us see the different genetic disorder types.

What are the Different Types of Genetic Disorders?
Some inherited genetic diseases are known at birth and whereas some take time to get expressed. There are over 4,000 genetic disorders in humans and scientists keep discovering new disorders with each passing day, as this list of genetic disorders goes on increasing. Basically, there are four types of genetic disorders; single gene disorder, multi-factorial, chromosomal abnormalities and mitochondrial mutations.

Single Gene Disorder
The single gene disorder, also known as Mendelian or monogenic disorder. This disorder occurs when the change or mutation occurs in only a single gene. The single gene disorders have high chances of being passed down from parent to children. These disorders include:

• Autosomal disorders: They arise from one abnormal gene coming from a single parent. For example, achondroplasia.
• Autosomal recessive: This is due to an abnormal gene from both parents. For example, sickle cell anemia and cystic fibrosis
• X-Linked: These abnormalities are formed due to a single abnormal gene on the X chromosome. For example, hemophilia. There are X-linked dominant and X-linked recessive disorders. The X-linked dominant gene affects both, male and female population. In X-linked recessive disorders, men are more commonly affected, when compared to females.
• Y-Linked: In Y linked disorders, the mutation or abnormality is seen only on the Y chromosome. As only the males inherit the Y chromosome, only boys will inherit the disorder from their fathers. For example, male infertility.

Multifactorial
The multifactorial defect or polygenic problems are due to a combination of different factors like the effects of environment and lifestyle. Multi-factorial disorders include heart diseases, diabetes, hypertension, obesity, etc. The other environmental related multi-factorial disorders include:

• Asthma
• Autism
• Autoimmune diseases
• Cancer
• Ciliopathies
• Cleft palate
• Mental retardation, etc.

Chromosomal Abnormalities
The mutations that occur in chromosomes can lead to changes in various genetic information. This leads to chromosomal abnormalities like aneuploidy, that includes Down syndrome, Turner syndrome, chromosomal sequence deletion, inversion of chromosomal sequence and even translocation.

Mitochondrial Mutations
This follows a pattern of maternal inheritance as it is related to the mitochondrial DNA. Mitochondria is contributed only by the egg cells to the developing embryo. Thus, only mothers can pass mitochondria disorders to their children. For example, Leber's Hereditary Optic Neuropathy.

These were the different genetic disorder types in humans that may be expressed due to mutation. I hope this article on genetic disorders in humans has helped answer your question as to what are the different types of genetic disorders and has helped you understand them.