Diseases that “are passed on from parents to children” are commonly referred to as hereditary diseases. Genetic diseases are divided into three groups: chromosomal abnormalities, monogenic diseases, and hereditary polygenic diseases.
What are hereditary diseases?
Hereditary diseases are clinical pictures or illnesses that arise from errors in the genetic make-up or arise from mutations (spontaneous mutations due to environmental influences, infections during pregnancy, etc.).
Hereditary diseases are always caused by changes in individual chromosomes or chromosome segments (genes). Chromosomes occur in the cell nuclei of all multicellular living beings and contain the genetic information in the form of DNA strands on which the individual genes are located.
Humans have a total of 46 chromosomes in each cell nucleus, two of which are sex-determining (XX, XY). The remaining 44 chromosomes are crucial for the development and function of individual organs, with the individual genes having a specifying effect.
Causes
Any chromosome or gene can be damaged and cause serious hereditary diseases. In inherited chromosomal diseases, there is an abnormality in the number or structure of the chromosomes. Well-known hereditary diseases in this category are trisomy 21 (Down syndrome), Klinefelter syndrome (XXY) and Turner syndrome (only one X chromosome). These hereditary diseases often manifest themselves with reduced intelligence, altered physiognomy and physical impairments of varying degrees of severity.
In a monogenic disorder, only one gene is defective. These hereditary diseases occur frequently, complicate and hinder, for example, the formation of enzymes and proteins and are responsible for most metabolic diseases. Hemophilia, sickle cell anemia, and albinism are also among these hereditary diseases.
Monogenic defects can be inherited, but can also arise spontaneously. In the case of polygenic or multifactorial hereditary diseases, several genes are affected, which interact with one another in an incorrect way. Often, environmental influences are also decisive. This applies, for example, to the cleft palate, hereditary forms of schizophrenia and some allergies.
Typical & common hereditary diseases
- Down syndrome (trisomy 21)
- Turner Syndrome
- Cleft lip and palate (Cheilognathopalatoschisis)
- Kidney cyst (cyst kidneys)
- cretinism
- Alpha-1 antitrypsin deficiency
- Cystic fibrosis
- Haemophilia (blood disorder)
- Phenylketonuria (PKU)
- Huntington’s Disease (Huntington’s Disease)
Symptoms, ailments & signs
Due to the large number of hereditary diseases, it is impossible to describe symptoms and complaints in a standardized way. Most hereditary diseases, however, are characterized by the fact that the symptoms that accompany them appear at a certain point in life and eventually worsen. In many cases, they mean a lifelong limitation of the person concerned and can in some cases significantly shorten their lifespan.
Symptoms include metabolic disorders, nerve degeneration and genetic blindness. Since a genetic predisposition to certain ailments can be defined as a hereditary disease in the broadest sense, in some cases ailments such as heart attacks, an increased susceptibility to tumor formation and osteoporosis also fall into the group of symptoms.
Signs of hereditary diseases are often that offspring show symptoms that were already known to their parents or grandparents. The suspicion of the presence of a hereditary disease is then obvious. However, this can only be quickly assumed in the case of autosomal dominant inheritance, since autosomal recessive inheritance can be inherited by one or more generations without manifesting a disease.
In order to get an overview of the symptoms and possible signs of a hereditary disease, it makes sense for the descendants of carriers of such genes, as well as the carriers themselves, to familiarize themselves with the respective inheritance and occurrence probabilities.
Diagnosis & course
An accumulation of certain illnesses in the family can indicate hereditary diseases. Monogenic defects are difficult to diagnose and are often referred to as a “predisposition” rather than a hereditary disease. Whether and how severely the individual clinical pictures occur in the more relevant chromosomal hereditary diseases depends on whether only parts of a chromosome are damaged, one chromosome is completely missing or even appears twice.
Gender-specific hereditary diseases (X, XXY) are often associated with reduced intelligence and / or infertility. Most damage to the chromosomal genetic material does not result in a viable organism. Nature helps itself with these acute hereditary diseases and the embryo is rejected.
Many hereditary diseases therefore remain undetected. Carriers of a genetic defect do not have to show the corresponding clinical picture themselves, but they can inherit the defect in a recessive or dominant manner. Incestuous associations often produce offspring with hereditary diseases.
Complications
The complications depend very much on the hereditary disease itself and its treatment. In many cases it is possible to limit and combat the symptoms and complications with the help of early treatment. In severe cases, however, direct treatment is not possible, so that only the symptoms can be treated in order to make life and everyday life easier for the patient.
In most cases, hereditary diseases cause problems with intelligence and motor skills. This leads to mental and physical retardation. This leads to severe social problems, bullying and teasing, especially in children. With some hereditary diseases, there is a strong reduction in life expectancy due to the manifestation of different diseases.
This is especially the case when the immune system is significantly weakened and cannot provide a permanent defense. A hereditary condition cannot be treated initially, so treatment is only designed to reduce symptoms. In many cases, therapies are available that reduce symptoms and enable the patient to lead a healthy life.
When should you go to the doctor?
Hereditary diseases should definitely not be taken lightly, so an examination by an appropriate specialist should definitely take place. Some hereditary diseases can even be diagnosed immediately after birth, so that subsequent care by a doctor is mandatory. Of course, it is always important what kind of hereditary disease is present. Some hereditary diseases require regular treatment and medical interventions in order to avoid serious consequential damage.
The intensity of a subsequent treatment is of course always dependent on the respective hereditary disease. In some cases, only a preventive examination is necessary, so that permanent treatment by an appropriate doctor does not have to be carried out. In other cases, certain hereditary diseases require regular examination or treatment, as otherwise permanent or even fatal consequential damage can result. For this reason, the following applies: an examination for hereditary diseases should definitely be carried out on every person. Such an early examination can determine a possible hereditary disease, so that possible complications can be avoided.
Treatment & Therapy
Most of the hereditary chromosomal diseases can already be identified in the embryonic stage by testing the amniotic fluid. The parents concerned must ultimately decide for themselves whether they want to give life to a disabled child.
However, the origins of the hereditary diseases are currently not treatable. Only the symptoms can be relieved with medication. Mentally handicapped children with trisomy 21 are now allowed to lead a largely independent life in adulthood, which is achieved through targeted support, among other things. The life expectancy of people with a hereditary disease (e.g. cystic fibrosis) has also increased significantly as a result of advances in medical science.
Children with a congenital, hereditary underactive thyroid (hypothyroidism) used to be inevitably classified as “feeble-minded” and suffered from short stature. The clinical picture of this hereditary disease was called cretinism. Today the disease is suppressed by the administration of artificial thyroxine (thyroid hormone) and iodine and the children can develop normally. Many hereditary diseases have lost their flaws and can be successfully treated, even if not (yet) curable.
Outlook & forecast
The prognosis of hereditary diseases is to be determined according to the individual disease. Since human genetics must not be interfered with, fundamental changes to the DNA are not possible. Hereditary diseases can therefore only be treated symptomatically. There are diseases in which the treatment of the complaints can achieve good results and a stable quality of life is achieved.
Surgical interventions provide innumerable correction options that help improve the situation. Often, however, several operations must be performed in the course of a person’s life in order to ensure the patient’s survival. Thanks to medical advances, scientists are continuously able to find new methods or options for treatment and to implement them successfully. Nevertheless, there are also hereditary diseases for which medicine can use little or no therapeutic methods.
Often the life span of the sick person is significantly reduced with genetic defects. In addition, reduced development, visual abnormalities or mental and motor impairments are to be expected. In addition to the physical characteristics of a hereditary disease, this often leads to mental illnesses that can further worsen a prognosis. In some cases, a fetus or newborn child is unable to survive. It dies in the womb or, despite all efforts, shortly after birth.
Prevention
The early detection of hereditary diseases is important in order to reduce the effects on body and mind as well as the impairment of quality of life. Gene defects that affect the metabolism can now be treated well. Early treatment reduces the severity of the clinical picture caused by such hereditary diseases and enables those affected to lead a largely normal life.
Aftercare
Follow-up care is very difficult for many hereditary diseases. Genetic defects or mutations can have such serious consequences that medical professionals can only mitigate, correct or treat a few of them. In many cases, hereditary diseases cause severe disabilities. Those affected have to struggle with these for life.
What can be done in aftercare often only consists of physiotherapeutic or psychotherapeutic measures. However, successful treatment can be achieved for a whole range of slowly progressing hereditary diseases. What these look like depends on the disease itself.
Hereditary diseases such as hemophilia, cystic fibrosis or Down’s syndrome each have very different clinical pictures. The same applies to the cleft palate and jaw, neurofibromatosis or cystic kidneys. The aftercare measures must be based on these clinical pictures.
Generalized statements about the type of follow-up care are only permissible to the extent that the affected patient’s life is made easier as far as possible. Hereditary diseases can cause symptoms that increase or remain constant throughout life. They can significantly reduce the quality of life and the lifespan. In the case of many hereditary diseases, operations do not provide much relief. Post-operative follow-up may be necessary.
Some of the symptoms or disorders of hereditary diseases can be treated successfully these days. Psychotherapeutic care is useful for hereditary diseases where the characteristics of the disease lead to depression, feelings of inferiority or other psychological disorders.
You can do that yourself
Hereditary diseases are genetic and are passed on from one generation to the next. The person concerned can usually not take any measures against the causes of a hereditary disease. Even conventional medicine is currently not usually able to treat a genetic disease causally.
In many cases, however, those affected can help to control the risks or to alleviate the severity of the course. What an affected person can actually do himself, however, depends on which hereditary disease he suffers or which hereditary diseases have already occurred in the family.
In the case of numerous hereditary diseases, a serious disorder can already be identified during prenatal diagnosis. Expectant parents, in whose families one or more hereditary diseases are common, should therefore make use of the preventive medical check-ups offered. In the case of a severe disability, you can then decide whether you want to interrupt the pregnancy prematurely.
On the other hand, some hereditary diseases only show up in adulthood. Here, the course of the disease and the prognosis for those affected often depend on the disorder being recognized early and adequately treated. People with hereditary diseases in their families should familiarize themselves with the course and accompanying symptoms so that they can correctly interpret the first symptoms and seek medical help promptly.
