Chromosomal mutations are changes to one or more chromosomes in an individual. These changes can be passed on to descendants. A consequence of such mutations may be disease, malformation, or disability.
What are chromosomal mutations?
Various changes are possible on a chromosome. This is because chromosomes can break apart, resulting in mutations. There are seven types of chromosomal mutation: Deletion involves the loss of a portion of a chromosome. The term “translocation” implies that chromosomes break apart and therefore lose fragments that attach to other chromosomes. Duplication is when part of a chromosome is duplicated because the broken apart part of another chromosome has become incorporated. Inversion is when a chromosome breaks in duplicate and parts reinsert in the wrong order. Addition (or insertion) is when a chromosome has an additional fragment. A fusion, on the other hand, means that two chromosomes merge. The opposite is also possible: if a chromosome falls apart at its centromere, fission is the result. What these mutations have in common is that they are structural changes that are inherited by descendants when they are passed on to daughter cells. They can be partially visualized by light microscopy. Chromosomal mutations must be distinguished from gene mutations, in which only a single gene is altered. Such changes may be due to a variety of causes:
Causes
Various factors affect the genetic material of individuals. It is known that radiation such as radioactive radiation or UV radiation can alter genetic information. However, temperature upheavals such as cold shocks or very high temperatures can also have an effect. It is also known that toxins such as nicotine, alcohol and other drugs can potentially damage the genetic material. Mutations can also be triggered by viruses such as rubella or chickenpox, as well as gases such as ozone or industrial fumes. Research in recent decades has also shown that it is not only genetics that influence the individual, but also the experiences that the individual has can bring about a lasting change in the genetic material that is passed on to the offspring. In this respect, lifestyles and the social and material environment have an impact on hereditary information and can lead to breaks on or in chromosomes. Last, chromosome breakage can also be due to chance, without any detectable cause. The triggering factors of a mutation are called mutagens. The changes usually have negative consequences for the affected individuals.
Symptoms, complaints, and signs
The symptoms, complaints, and signs that develop as a result of one or more chromosomal mutations are completely different. The relevant question is which chromosomes have changed and how. It is known that numerous diseases, disabilities and malformations are due to chromosomal mutations. These can affect the physical, the mental and/or the spiritual sphere. The best known example of the consequences of a chromosomal mutation is translocation trisomy. This is a form of trisomy 21 (Down syndrome). In this case, parts of chromosome 21 are tripled because part of one chromosome has attached itself to another chromosome. The consequences are serious: those affected are more or less mentally impaired, have characteristic external features such as below-average height, slanted eyes, a tendency to be overweight, small ears and short fingers. Many have congenital heart defects or problems with the digestive system. Most cannot live independently and die earlier than the average population. Many work in sheltered workshops and require intensive care. Other examples of the consequences of a chromosomal mutation include catcry syndrome or Huntington’s disease (St. Vitus’ dance).
Course
It is always beneficial if an appropriate diagnosis for diseases, disabilities, and malformations is made as early as possible. This makes it possible to intervene therapeutically in a timely manner. Depending on the nature of the consequences of the alteration in or on chromosomes, the course of the disease varies. Mental disabilities, for example, cannot be reversed.
Complications
Chromosomal mutations can lead to a variety of diseases. These include mutations in the human genome that can cause neurodegenerative diseases. These are diseases in which the nervous system is damaged. Such diseases include Alzheimer’s disease, Huntington’s disease and Gerstmann-Sträussler-Scheinker syndrome. These diseases are characterized by the toxic accumulation of various proteins. This takes place in neurons, which is why movement is impaired or other functions such as memory are disturbed. To date, these diseases can only be treated to a minor extent. As the disease progresses, patients require increased assistance to cope with everyday life, up to and including full-time care. These diseases usually all lead to the death of the affected person. Furthermore, mutations in the DNA can lead to various forms of cancer. This is a disease that can occur in all tissues of the body. Due to a disturbance in cell growth, uncontrolled cell growth occurs. In this case, the affected area is removed, or radiation therapy is given. Patients require additional treatments depending on which tissue is affected. This can be a lengthy process, especially because a cured cancer can recur in the future. Therefore, regular screenings are important.
When should you go to the doctor?
In many cases, a chromosomal mutation can be diagnosed before birth. Pregnant women should definitely take advantage of the preventive examinations offered and make an additional appointment with a gynecologist in case of complications or an uneasy feeling. If any malformations, disabilities or diseases become apparent after birth, immediate clarification by a physician is necessary. In most cases, this is done routinely. However, sometimes signs of chromosomal mutation are not detected until later. In any case, immediate medical diagnosis and treatment is necessary, otherwise serious complications may develop. Parents who notice symptoms of a heart defect or digestive system disease in their child should consult the pediatrician immediately. In the case of severe malformations or disabilities, accompanying psychological advice should also be sought – initially only for the parents and later in life also for the affected child. An emergency physician should be consulted if complications arise and the child cannot breathe properly, for example, or shows the first signs of dehydration.
Treatment and therapy
However, if an intellectual disability such as trisomy 21 is present, those affected can be treated with the best possible support at an early stage. This means that they are individually socially integrated according to their needs. This also applies to mental disabilities based on a different chromosomal mutation. Since affected persons often also have physical problems, these must also be taken into account and treated at an early stage in order to enable them to lead a largely normal life. Treatment and therapy must always be oriented to the individual case and the given problem. The goal is always to enable individuals with a congenital chromosomal mutation and the resulting limitations to live as independently as possible and to participate in social life. Depending on the severity and treatability of the limitations, this may require different steps and measures: The spectrum ranges from casual care to placement in a nursing home. It should be noted that affected persons are dependent on a helpful social environment and early therapies from the very beginning.
Outlook and prognosis
A chromosomal mutation cannot be cured according to current possibilities. Therefore, the prognosis must be considered unfavorable. For legal reasons, intervention in human genetics is forbidden according to the current status in our society. Therefore, the only option left to medicine is to provide relief from the individual symptoms caused by the inherited mutation. Depending on the effects on physical health, it is increasingly possible to achieve an improvement in health. Although a cure is nevertheless not given, life-prolonging measures have become significantly more successful in recent years.Likewise, numerous therapeutic methods have been developed that lead to an immense improvement in the quality of life for many diseases. As soon as a person suffering from a chromosomal mutation begets offspring, he passes on his genetic defect to the next generation. Nevertheless, the effects can be quite different. In many cases, parents and children have the same diseases and symptoms. Likewise, the offspring may have significantly stronger or weaker symptoms. In some people, the existing chromosomal defect does not lead to any impairments. Nevertheless, it is present and can in turn lead to a completely different health picture in one’s own children. In addition, other diseases may result that contribute significantly to the overall health condition.
Prevention
Accordingly, the question arises as to how harmful changes in the genetic material can be prevented. In principle, it can be said that preventive measures are hardly possible. However, it has been proven that women aged 40 and older, for example, have a high risk of giving birth to a child with Down syndrome or other hereditary defects. It is also known that avoiding certain environmental and stimulant toxins is helpful. If in doubt, prenatal diagnostics can provide information about the child’s health condition.
Follow-up
In the case of a chromosomal mutation, options for aftercare prove relatively difficult in most cases. In this regard, these conditions cannot be completely prevented or treated by a doctor, so the measures of an aftercare depend very much on the exact treatment of the disease. An independent cure cannot occur with a chromosomal mutation, so that the affected person is always dependent on treatment by a doctor. If the affected person wishes to have children, genetic testing and counseling can also be performed to prevent the disease from recurring in the descendants. The symptoms of a chromosomal mutation can be relatively well alleviated by special and intensive support. The parents and relatives of the patient are especially needed in their support to enable the affected person to lead an ordinary life. In severe cases, however, the patient has to stay in a nursing home if the relatives cannot take over the care completely. The disease may also limit the life expectancy of the affected person. Since chromosomal mutation can also lead to malformations or deformities, these can also be corrected by surgery.
What you can do yourself
Possibilities for self-help are not given in the case of a chromosomal mutation occurring. This is because the chromosomes (and their damage) cannot be influenced in any way. It can only be tried to deal with resulting disease patterns. For example, the oncogenes that occasionally arise can lead to cancer, which in turn requires completely different measures for self-help. The same applies to trisomies. Chromosomal mutations that are already present at birth because they arose from one of the two germ cells not infrequently lead to considerable impairment of the individual. Often the mutations are lethal, if they do not only affect a small cell focus. Accordingly, all measures for self-help are not applicable here either. Only medical help can be useful, as far as the occurring damages are treatable. In the case of persons who have disease patterns that are in turn due to such mutations, an examination of the germ cells can be a good help in family planning. After all, all chromosomal mutations are heritable insofar as they also occur in the germ cells. Accordingly, these cells can be tested to minimize any risks in family planning. Since trisomies can also be traced back to chromosomal mutations and these usually occur more in the germ cells with increasing age, screening tests can also be useful here.
