The 3 Differences Between Genetic and Hereditary Diseases
Human genetic material is a vast information network that defines people and determines the functioning of the human body. Alterations in this material can cause the appearance of genetic and hereditary diseases, but are there differences between these terms?
The use of the words genetic and hereditary as synonyms is a very common mistake throughout the world. Many people use both words indiscriminately to describe diseases that affect the structure of a person’s DNA or to refer to congenital diseases.
Although these terms are closely related, there are small characteristics that allow us to differentiate one from the other. Distinguishing genetic diseases from hereditary ones is important, especially in the clinical field, so we’ll being you three differences between them.
What are genetic diseases?
In order to differentiate between the two types of diseases, it’s important to know what a genetic disease is. It can be defined as ‘a pathology produced by the alteration of a gene’, that is, in a segment of DNA that encodes a specific protein.
DNA contains all a person’s genetic information, although it has several levels of organization. A set of small structures called nucleotides make up the DNA strand. Various specific segments of that strand are known as genes, and the DNA condenses to form a chromosome.
All genetic diseases are produced by the modification of one or more genes of the DNA chain, being able to alter the synthesized protein. Most of these modifications occur due to a mutation, that is, the alteration in one or more nucleotides of the DNA chain.
These types of diseases are very common throughout the world, in fact, studies estimate that they affect up to 7% of the world’s population. Today, more than 10,000 genetic diseases have been described, many of which can be fatal.
What are hereditary diseases?
On the other hand, hereditary diseases are ‘pathologies that can be transmitted from one generation to another’. In other words, they’re the diseases that parents can transmit to their children through any of the different theories of inheritance.
This type of condition is caused by alterations in a person’s sex cells. It is important to note that all people have somatic cells and sex cells or gametes. All of these cells contain the same genetic information, with a few exceptions.
Somatic cells are those that make up all the structures of the body, while gametes are eggs and sperm. The latter are responsible for transmitting information to a new generation, so a mutation in these cells can generate hereditary diseases.
Multiple studies establish that the probability that an individual will suffer from some hereditary disease will depend on the genetic load of the parents and the corresponding inheritance pattern. In this sense, there may be a risk of between 25% and 100% of having offspring affected by this type of disease.
3 differences between genetic and hereditary diseases
As you can see, both types of diseases are very similar, but still shouldn’t be used synonymously. Both types of pathologies have certain differences between them, among which the following stand out:
1. The ability to transmit the disease to their offspring
One of the main differences between genetic and hereditary diseases can be established in this section. All hereditary diseases are genetic, since they are due to an alteration in DNA and RNA, however, not all genetic pathologies are hereditary.
In this sense, there are certain alterations in the genes that can be transmitted from parents to children, such as achondroplasia or cystic fibrosis. On the other hand, there are genetic abnormalities in which the person isn’t capable of transmitting their condition to their children.
An example of a non-inheritable genetic disease is Down’s syndrome, except when it’s the product of a translocation. This is a chromosomal disease characterized by the presence of an extra chromosome 21, usually due to an error during the division of one of the gametes.
2. Cells that are affected
The DNA abnormality must be found in the parents’ sex cells in order for a disease to be inherited. In this sense, one or both gametes of the parents must be affected by the mutation in order for the disease to be transmitted, so hereditary pathologies are related to sex cells.
On the other hand, genetic diseases can affect both somatic cells and gametes. Somatic cells are more abundant in the human body, which is why most genetic conditions usually involve them.
One of the diseases caused by a somatic mutation of some type of cancer. For example, breast cancer appears by a mutation in a cell of the mammary gland, however, there’s no involvement of the maternal eggs.
3. The person suffering from the disease
In theory, genetic diseases only affect the person who is being studied, that is, the pathology affects the person that has the mutation. It’s important to take into account that the disease may or may not be transmitted to their offspring according to the points described.
The concept of hereditary disease establishes that the offspring of the person who has the alteration is the one who will suffer the consequences of the pathology. The parents may or may not suffer from the disease.
Very similar terms that shouldn’t be confused
One of the main differences between genetic and inherited diseases is the ability to pass the disease on to the next generation. A good way to summarize and highlight the main idea is to remember that all hereditary diseases are genetic, but not all genetic diseases are hereditary.
Both diseases are governed by very similar genetic bases and can appear at any time in life. The study of genes has come a long way over the years, and today it’s possible to determine the precise alteration of many diseases.
- Abarca Barriga HH, Chávez Pastor M, Trubnykova M, La Serna-Infantes JE, Poterico JA. Factores de riesgo en las enfermedades genéticas. Acta Med Peru. 2018;35(1):43-50.
- Muñoz-Nuñez M, Giron J, Molina L, Fernández L et al. Enfermedades hereditarias y técnicas de detección preimplantacionales. Revista Iberoamericana de Fertilidad. 2005; 22(5): 343-359.
- González-Lamuño D, García Fuentes M. Enfermedades de base genética. Anales Sis San Navarra. 2008; 31(Suppl 2): 105-126.
- Goss C. Genetic disorders. JEMS. 2014 Feb;39(2):64-71.
- Löwy I. How diseases became “genetic”. Cien Saude Colet. 2019 Sep 26;24(10):3607-3617.
- Mössner J. Genetische Erkrankungen und ihre Diagnostik [Diagnostic Procedures in Hereditary Diseases]. Dtsch Med Wochenschr. 2017 May;142(9):633-634.