Hereditary diseases are clinical pictures or diseases that are caused by errors in the hereditary disposition or are newly formed by mutations (spontaneous mutations due to environmental influences, infections during pregnancy, etc.).

Hereditary diseases are always caused by a change in individual chromosomes or chromosome sections (genes). Chromosomes are found in the cell nuclei of all multicellular organisms and contain the hereditary 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, of which two chromosomes 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

Every chromosome and every gene can be damaged and cause serious hereditary diseases. In hereditary chromosomal diseases, there is an abnormality in chromosome number or structure. 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 the formation of enzymes and proteins, for example, and are responsible for most metabolic diseases . Haemophilia, sickle cell anemia and albinism are also among these hereditary disorders.

Monogenic defects can be inherited, but they can also arise spontaneously. In the case of polygenic or multifactorial hereditary diseases, several genes are affected, which interact with each other in a faulty manner. Environmental influences are often also decisive. This applies, for example, to the cleft palate, hereditary forms of schizophrenia and some allergies .

Typical & common hereditary diseases

• Down-Syndrom (Trisomie 21)
• Turner Syndrome
• Cleft lip and palate (cheilognathopalatoschisis)
• renal cyst (cystic kidneys)
• Cretinism
• Alpha-1-Antitrypsinmangel
• cystic fibrosis
• Hemophilia (bleeding disease)
• Phenylketonurie (PKU)
• Chorea Huntington (Huntington-Krankheit)

Symptoms, Ailments & Signs

Due to the large number of hereditary diseases, it is impossible to describe symptoms and complaints in a standardized way. However, most inherited diseases are characterized by the fact that the symptoms associated with them appear at some point in life and eventually worsen. In many cases, they mean a lifelong limitation for the person concerned and can sometimes shorten their lifespan considerably.

Symptoms include metabolic disorders, nerve degeneration and genetic blindness. Due to the fact that a genetic predisposition to certain diseases can also be defined as a hereditary disease in the broadest sense, in some cases diseases such as heart attacks, an increased susceptibility to tumor formation and osteoporosis also fall within the group of symptoms.

Signs of hereditary diseases often consist in the fact that offspring show symptoms that were already known to 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 for one or more generations without the development of a disease.

In order to get an overview of the symptoms and possible signs of a hereditary disease, it makes sense for the offspring of those who tend to be carriers of such genes, as well as for the potential carriers themselves, to familiarize themselves with the relevant inheritance and occurrence probabilities.

Diagnosis & History

An accumulation of certain diseases in the family can indicate hereditary diseases . Monogenetic defects are difficult to diagnose and are often referred to as “predisposition” and not as a hereditary disease. Whether and how severe the individual clinical pictures occur in the more relevant chromosomal hereditary diseases depends on whether only parts of a chromosome are damaged, a chromosome is missing completely or even occurs twice.

Gender-specific hereditary diseases (X, XXY) are often associated with reduced intelligence and/or infertility . Most damage to the chromosomal genome does not produce a viable organism. Nature helps itself with these acute hereditary diseases and the embryo is rejected.

Many hereditary diseases thus remain undetected. Carriers of a genetic defect do not have to have the corresponding clinical picture themselves, but they can inherit the defect recessively or dominantly. Incestuous unions 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 serious cases, however, treatment is not directly 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 lead to problems with intelligence and motor skills. This leads to mental and physical retardation. This leads to strong social problems, bullying and teasing, especially in children. Some hereditary diseases lead to a sharp reduction in life expectancy due to the development of different diseases.

This is especially the case when the immune system is significantly weakened and cannot provide a permanent defense. An inherited disease cannot be treated originally, so treatment is designed only to reduce symptoms. In many cases, therapies are possible that limit the symptoms and enable the patient to live a healthy life.

When should you go to the doctor?

Hereditary diseases should definitely not be taken lightly, so an examination by a specialist should definitely take place. Some hereditary diseases can even be detected immediately after birth, so that subsequent care by a doctor is mandatory. Of course, it is always significant what kind of hereditary disease is present. Some hereditary diseases require regular treatment and medical intervention to prevent serious complications.

The intensity of subsequent treatment is of course always dependent on the respective hereditary disease. In some cases, only a preventive check-up is necessary, so that permanent treatment by an appropriate doctor is not necessary. In other cases, certain hereditary diseases require regular examination or treatment, as otherwise permanent or even fatal consequences can result. For this reason, the following applies: An examination for hereditary diseases should definitely take place with every person. Such an early examination can identify a possible hereditary disease, so that possible complications can be avoided.

Treatment & Therapy

Amniotic fluid tests can already detect most chromosomal hereditary diseases in the embryonic stage. Ultimately, the parents concerned must decide for themselves whether they want to give birth to a disabled child.

However, the origins of the hereditary diseases are currently untreatable. Only the symptoms can be alleviated with medication. For example, mentally handicapped children with trisomy 21 are now allowed to lead largely independent lives as adults, 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 congenital, hereditary hypothyroidism (hypothyroidism) used to be inevitably classified as “demented” and suffered from short stature . The clinical picture of this hereditary disease is 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 blemishes and can be successfully treated, even if they cannot (yet) be cured.

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 in the DNA are not possible. Hereditary diseases can therefore only be treated symptomatically. There are diseases in which good results can be achieved and a stable quality of life can be achieved by treating the symptoms that arise.

Surgical interventions provide countless correction options that contribute to improving the situation. Often, however, several surgeries must be performed over the course of life to ensure the survival of the patient. Thanks to medical progress, scientists are continually able to find and successfully implement new methods or options for treatment. Nevertheless, there are parallel hereditary diseases for which medicine can apply little or no therapy.

The lifetime of the patient is often significantly reduced in the case of 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, mental illnesses often occur, which can further worsen the prognosis. In some cases, a fetus or newborn child is not viable. It dies in the womb or, despite all efforts, shortly after birth.

prevention

Early detection of hereditary diseases is important in order to reduce the effects on body and mind as well as the impairment of the quality of life. Genetic defects that affect metabolism can now be treated effectively. 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 consists only of physiotherapeutic or psychotherapeutic measures. However, successful treatment can be achieved for a whole series of slowly progressing hereditary diseases. What these look like depends on the disease itself.

In the case of hereditary diseases such as hemophilia , cystic fibrosis or Down’s syndrome, very different clinical pictures are found. The same applies to the cleft palate, neurofibromatosis or cystic kidneys. The aftercare measures must be based on these clinical pictures.

General statements about the type of aftercare are only permissible to the extent that life is made easier for the patients concerned. Hereditary diseases can cause increasing or constant severe symptoms throughout life. They can significantly reduce quality of life and lifespan. In the case of many hereditary diseases, operations provide little relief. Postoperative follow-up care may be necessary.

Some of the symptoms or disorders of inherited diseases can now be successfully treated. Psychotherapeutic care makes sense for hereditary diseases where the characteristics of the disease lead to depression, feelings of inferiority or other mental disorders.

You can do that yourself

Hereditary diseases are genetic and are passed on from one generation to the next. In most cases, the person affected cannot take any measures against the causes of a hereditary disease. Conventional medicine is currently generally not able to treat a genetically caused disease causally.

In many cases, however, those affected can help to control the risks or mitigate the severity of the course. What an affected person can actually do himself depends on which hereditary disease he is suffering from 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 diagnostics . Parents-to-be whose families have one or more hereditary diseases should therefore make use of the check-ups offered. In the event of a severe disability, they can then decide whether they want to terminate the pregnancy prematurely.

In contrast, some hereditary diseases only become apparent in adulthood. The course of the disease and the prognosis for those affected often depend on the disorder being recognized early and treated adequately. People in whose families hereditary diseases occur should familiarize themselves with the course and side effects of the diseases so that they can correctly interpret the first symptoms and seek medical help promptly.