Difference between genetic, inherited and congenital diseases

The concepts of genetic, hereditary, and congenital disease are often misleading. Sometimes we refer to certain diseases that appear from birth or that are transmitted from one family member to another using terms that are not interchangeable, not all congenital diseases are inherited and vice versa. That is why it is important to distinguish these 3 terms:

What are genetic diseases?

A genetic disease is one that develops due to changes or alterations in DNA. Sometimes genetic diseases can be hereditary and / or congenital. In fact, there are genetic diseases that do not appear from birth, but can develop throughout life and do not manifest symptoms until adulthood.

What are hereditary diseases?

A hereditary disease is the one that is transmitted through the genetic material from fathers (or mothers) to their children. The fact that it is a hereditary disease does not mean that it manifests itself at birth, that is, may or may not be congenital. On the other hand, although hereditary diseases are caused by genetic alterations, this does not imply that, if one of the parents suffers from or is a carrier of the disease, he will transmit it to all his offspring (it will depend on the patterns of hereditary transmission).

The most common inherited diseases

• Cystic fibrosis, which causes the accumulation of thick mucus and secretions in the lungs and also in the pancreas, liver and intestines.
• Huntington's disease, which affects neurons and causes movement disorders.
• Sickle cell anemia, which alters the shape of the red blood cells and alters their ability to transport oxygen.
• Myopia, which impairs the ability to see distant objects clearly.
• colour blindness, in which the ability to recognize certain colors is impaired.
• Primary dyslipidemias, in which fat metabolism is altered regardless of intake.
• Phenylketonuria, which can cause brain damage due to the accumulation of an amino acid.
• Hemochromatosis, which causes an excessive accumulation of iron in the tissues, especially at the liver level.
• Neurofibromatosis, which causes characteristic spots on the skin and tumors of the skin and of the central nervous system; it is a hereditary and congenital disease.

These listed diseases depend on single gene and its inheritance can be transmitted following various patterns depending on which chromosome the altered gene is on. Other diseases depend on the alteration of several genes on different chromosomes, which means that their inheritance does not follow such a defined pattern, such as high blood pressure, diabetes, obesity, asthma or Alzheimer's disease.

What are congenital diseases?

A congenital disease is the one that is present from birth of the baby and can be transmitted by the parents or not. Many of these diseases have a genetic basis, but others may be due to environmental factors, such as the mother's exposure to certain drugs, toxic substances, or infections during pregnancy. It is estimated that there are more than 4,000 congenital diseases which can range from mild processes to serious affectations that can affect more than one organ or systems.

Congenital diseases can be structural, if there is a malformation of any internal or external viscus (head, neck, spine, trunk, genitalia or extremities) or metabolic that affect the functioning of an organ without altering its structure. Some of these congenital diseases are:

• Cleft lip and palate.
• Spina bifida
• .
• Presence of elevated scapula.
• Clubfoot.
• Congenital inguinal hernia.
• Interatrial communication.
• Ureteral duplication.
• Achondroplasia.
• .
• Congenital toxoplasmosis.
• Fetal alcohol syndrome.

Can they be diagnosed before birth?

For some of these diseases, there are prenatal tests, such as that, that help to recognize the risk of Down syndrome or spina bifida. These tests are usually completed with others such as the amniocentesis or chorion biopsy. General Medicine Specialist