What are hereditary diseases?
Inherited diseases are genetic diseases that are transmitted by parents through DNA. They are very common, especially because one is often unaware that one is a healthy carrier of a certain disease: in most cases, in fact, hereditary diseases are discovered only if the child is affected, as a result of the fact that the partner was also, without his or her knowledge, a healthy carrier.
How are they transmitted?
The rules for the transmission of hereditary diseases between generations are very precise and can be divided into two main groups: multifactorial diseases and monogenic diseases. The former are caused by a combination of genetic and environmental factors: hypertension, celiac disease, diabetes, colon cancer and heart disease are just a few examples; genetic factors are the hereditary component of the multifactorial disease, which, however, will only manifest itself when environmental factors come into play. Monogenic diseases, however, are caused by the alteration of a single gene: we are all carriers of many genetic mutations, but only a few are harmful and cause disease; in this case transmission follows the laws discovered by Mendel, whose hereditary mechanisms are:
- Autosomal recessive
- Autosomal dominant
- X-linked recessive
- X-linked dominant
Hereditary diseases are genetic diseases
Symptoms of inherited diseases
The symptoms of hereditary diseases change depending on the type of disease.
Diagnosis of hereditary diseases
Diagnosis can be made before delivery thanks to amniocentesis, i.e. DNA study, which consists in performing several tests on the fetus, including multiple genetic screening, in order to detect (if necessary) the most common genetic diseases in the population. In Italy there are more than 6 000 hereditary diseases and the most common are:
- Mediterranean anemia (1 in 2 500 children).
- cystic fibrosis (1 in 2,700 children)
- congenital deafness (1 in 4,000 children)
- Fragile X syndrome (1 in 4,000 children).
What are the causes of inherited diseases?
The common cause of all hereditary diseases is the mutation or defect of a DNA gene: however, depending on the type of disease, the gene affected by these mutations changes. Treatments for hereditary diseases To date, some hereditary diseases cannot yet be definitively cured, but treatments are being administered to reduce symptoms and improve patients’ quality of life. This is the case, for example, of cystic fibrosis, whose palliative treatments are antibiotics, bronchodilators, mucolytics, digestive enzymes and vitamins. In the case of Mediterranean anemia, however, the main treatments are blood transfusions, bone marrow transplants or stem cell transplants accompanied by a special diet.
Which specialist to contact?
Depending on the hereditary disease, one or the other specialist should be contacted. For congenital deafness, for example, we turn to an otolaryngologist, while for cystic fibrosis, to a pulmonologist.