They refer to different but easy to confuse concepts.
To clarify the meaning of these terms, in this article we discuss the definitions of genetic, congenital, and hereditary. They are commonly heard in relation to problems with newborns , although genetic and hereditary disorders can be suffered by anyone.
The meaning of genetic, congenital and hereditary
We start by defining each term so that we know in what context they should be used:
1. Concept of genetics
When we talk about something of a genetic nature, we are referring to what has to do with genetic material, usually DNA. This concept is widely used in research and science, especially in biology, to talk about any process related to or caused by DNA.
DNA is the vehicle through which we pass on our genetic information to our descendants, as well as being the instructions for the formation and development of living beings. When we talk about genetic disorders, we refer to pathologies and disorders that are caused by modifications in the DNA , such as mutations in the code or chromosomal aberrations.
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2. Concept of hereditary
When we talk about something hereditary, it refers to what comes from our ancestors, in the form of inheritance. In the medical-scientific field, the term “heritable” is used to talk about characteristics that are capable of being transmitted to offspring through genes, rather than those similarities between relatives that are the result of non-biological factors, such as education. or economic capacity.
To carry out genetic calculations, the concept of heritability refers to the portion that, among the entire range of phenotypic variability between individuals, correlates with genetic factors, ruling out environmental ones.
3. Concept of congenital
The term congenital refers to something that we have from birth , that is ours from the moment we exist and is not something that we have obtained or developed over the years. In medicine and science it is commonly used to talk about disorders that occur in babies during the gestation period.
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Examples and differences between the concepts
To internalize the differences between these terms, we are going to explain examples of genetic, congenital and hereditary disorders, so that the distinction between these three in the medical field will be clearer.
1. Example of a genetic disorder
Genetic disorders cause more than 6,000 human diseases, including cancer . They occur when the genetic material presents an alteration, which can be congenital or acquired during life.
Usually the alterations in our DNA acquired under normal conditions (for example, people who have not been in contact with high doses of ionizing radiation) are limited to small point mutations in some cells. These mutations usually have no effect on the cell, but depending on where they occur and the number of them, they can cause disorders such as neoplasms .
Congenital mutations can be more or less serious. Congenital point mutations can occur, as is the case with cystic fibrosis . People with this genetic disease are usually carriers of a mutation that affects a few nucleotides of the CFTR gene.
In other cases, congenital mutations can affect entire chromosomes. This is the case of Robertsonian translocations, for example. These types of mutations fuse chromosomes, reducing the number of chromosome pairs in the karyotype of their carriers.
In humans, it can be the Robertsonian translocation of chromosome 21 next to chromosome 14, which gives rise to phenotypically normal individuals, but who have a greater probability of having children with trisomies of chromosome 21. 5% of Down syndrome cases are related with these types of mutations .
2. Example of hereditary disorder
Hereditary disorders, in the medical field, are necessarily genetic , since they have to be passed on to offspring. These disorders can be directly DNA-related as well as, as recently observed, have epigenetic causes.
Epigenetic factors are of an acquired nature, adjustments that our body makes to our gene expression in response to the environment. It has been seen that some of them are heritable from parents to children , as in the case of epigenetics related to intense stress in parents that predisposes children to suffer from diseases such as depression or anxiety disorders.
3. Example of congenital disorder
Congenital disorders can have a genetic, infectious or environmental origin, but all of them appear during the development of the fetus during gestation. Every year around the world, more than 300,000 newborns die during the first month of life, due to congenital anomalies .
The most common are cardiac malformations, followed by neural tube defects and Down syndrome, which also has a genetic origin as it is due to genetic mutation and is considered heritable. The fact that Down syndrome is considered a congenital disease is due solely to the fact that clinical manifestations of the syndrome occur during pregnancy.
There are preventable congenital disorders with the action of the mother , for example through vaccination, intake of folic acid (which prevents spina bifida) or through correct nutrition and prenatal care.
More than half of congenital anomalies have a non-specific cause, but the predisposing factors for them are mainly socioeconomic and demographic (such as age and income of the parents), genetic, infectious as in the case of syphilis or due to environmental contamination , such as exposure to chemicals such as Agent Orange or Thalidomide.
Bibliographic references
- WHO (2016) Congenital anomalies. Retrieved from www.who.int/en/news-room/fact-sheets/detail/congenital-anomalies on 07/23/2019.
- Genetics Alliance; The New York-Mid-Atlantic Consortium for Genetic and Newborn Screening Services. Understanding Genetics: A Guide for Patients and Medical Professionals in the New York and Mid-Atlantic Region. Washington (DC): Genetic Alliance; 2009 Jul 8. Chapter 2, Diagnosis of a genetic disease. Retrieved from www.ncbi.nlm.nih.gov/books/NBK132200/.
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