Tauopathies represent a group of neurodegenerative diseases caused by the deposition of tau proteins in the brain. Alzheimer’s disease is considered the best-known tauopathy. To date, there is no cure for these degenerative diseases.
What is tauopathy?
Tauopathy is a collective term for several neurodegenerative diseases, all of which are associated with the development of dementia. All tauopathies are caused by the deposition of tau proteins in the brain. Tau proteins are named after the Greek letter tau. They bind to cytoskeletal proteins to perform supportive functions in animal and human cells. Normally, tau proteins link together via repetitive stretches to form filamentous structures in the cell. During linkage, the amino-terminal end of the polypeptide chain is truncated by phosphorylation. However, when hyperphosphorylation (saturation of all binding sites with phosphate groups) occurs, a protein is formed that is no longer functional and cannot form a bond with the proteins of the cytoskeleton. The protein is deposited in the brain. Hyperphosphorylation is favored by certain mutations. Six different isoforms are known for the tau protein, which can produce multiple forms of tauopathies if the appropriate genetic changes are made. Depending on the isoform, a tau protein can contain between 352 and 757 amino acids. The deposition of hyperphosphorylated tau proteins in the brain can lead to the development of Alzheimer’s disease, chronic traumatic encephalopathy (CTE or dementia pugilistica), among other diseases. Frontotemporal dementia (Pick’s disease), corticobasal degeneration, neurofibrillary tangle dementia, progressive supranuclear gaze palsy, or silver grain disease are also known to result. For all tauopathies, there is as yet no cure.
Causes
The cause of tauopathies represents the deposition of tau proteins in the brain. At the sites in the brain where these increasingly large deposits are found, functional impairment occurs, eventually leading to the death of neurons and glial cells. This causes the brain to shrink. It can shrink by up to 20 percent in the course of Alzheimer’s disease. Over time, important structures of the brain are thus lost. As a rule, this process is very slow, so that tauopathy leads to death after an average of eight years from onset. The basis of the deposition of tau proteins is their inability, as a result of hyperphosphorylation, to form sufficient bonds with the proteins of the cytoskeleton. Hyperphosphorylation can be caused by mutations. Approximately 60 different mutations of the tau gene have been discovered, all of which lead to tauopathy. Hyperphosphorylation is actually a normal process that serves as a signaling mechanism to trigger cell division. However, certain mutations increase hyperphosphorylation and produce, among other things, waste products of the tau protein that are no longer capable of binding and are thus functionless. One form of tauopathy, chronic traumatic encephalopathy, is not genetically determined, however, but is caused by frequent head injuries. Here, too, hyperphosphorylation of tau proteins occurs. It is possible that the phosphorylation here is triggered by regulatory processes. After injury, cell division must be stimulated for healing. However, this is stimulated by the signaling effect of phosphorylation.
Symptoms, complaints, and signs
The main symptom of tauopathy is the development of dementia. This is true for all forms of tauopathies. Alzheimer’s disease is considered the best-known example of this group of diseases. The term Alzheimer’s is often equated with dementia. However, this is not correct. Dementia is only the main symptom of this disease. All other diseases of this form group also develop dementia as the most important symptom. Alzheimer’s disease begins insidiously with general forgetfulness. In a further stage, the patient loses the simplest practical skills such as dressing or making coffee. In the final stage, patients suffer from apathy, loss of appetite, bedriddenness and incontinence. He can no longer recognize close persons. Corticobasal degeneration (CBD) is another disorder.In this disease, in addition to dementia, symptoms similar to those of Parkinson’s disease occur. Tremor, depression, anxiety, immobility, gait disturbances and eye movement disorders occur. In Pick’s disease, the focus is on behavioral problems and impaired performance. Progressive dementia also develops in this case. Progressive supranuclear gaze palsy is characterized by failure of the eye muscles and a Parkinson’s-like clinical picture. Silver grain disease is thought to be a special form of Alzheimer’s disease. Chronic traumatic encephalopathy is a tauopathy caused by external influences such as head injuries. Martial artists and boxers are particularly at risk of suffering from this disease in later years. This disease starts with headaches and concentration disorders. In the further course, a disturbed short-term memory, depression and emotional outbursts are added. In a final stage, the patient suffers from pronounced dementia, which makes it impossible for him or her to still cope with everyday life.
Diagnosis and course of the disease
The diagnosis of tauopathies is made by self- and external history. Furthermore, several neuropsychological tests such as the clock test or the Mini-Mental Status Test (MMST) are performed. Imaging techniques such as CT and MRI are also part of the diagnostic process. The symptoms that occur provide clues to the type of tauopathy.
Complications
Unfortunately, tauopathy cannot be completely cured, so there is no completely positive course of disease in this disorder. The affected persons suffer from different complaints in this case. It comes thereby to a loss of appetite and to an incontinence. Inner restlessness or confusion can also occur and have a very negative effect on the patient’s daily life. Many patients are then dependent on the help of other people in their lives and can no longer do many things in everyday life on their own. Depression or a tremor also occur in tauopathy. Furthermore, most patients suffer from behavioral problems and gait disorders. A loss of coordination can also occur. Due to the confusion, the risk of injuries increases enormously, so that the affected persons can also lose consciousness. Likewise, patients often suffer from headaches or concentration disorders. The symptoms of tauopathy can be limited with the help of medication. No complications occur in this process. However, a complete cure cannot be achieved. Whether there is a reduced life expectancy of the patient due to this disease cannot be predicted in general.
When should you see a doctor?
The affected person is dependent on a physician with a tauopathy. It cannot come with this illness to an independent healing, so that a treatment must be accomplished by a physician in any case. Only a correct and quick therapy can prevent further complications and discomfort. However, a complete cure is not possible with tauopathy, as it is a hereditary disease. Should the affected person wish to have children, genetic counseling should also be performed to prevent inheritance of the disease. A doctor should be consulted for tauopathy if the affected person suffers from severe loss of appetite and incontinence. In many cases, there is depression or difficulty with movement. Many also show abnormal behavior in tauopathy, which should also be checked by a doctor. Thereby also strong complaints of concentration or strong headaches can point to this disease. In the first place, tauopathy can be detected by a general practitioner or by a pediatrician. Further treatment depends on the exact complaints and is carried out by a specialist.
Treatment and therapy
Tauopathies cannot yet be treated causally today. In the context of Alzheimer’s disease, various drugs are administered, among other things, to improve memory. Symptomatic treatments are also given in the other tauopathies to improve symptoms and delay disease progression.
Prevention
Although most tauopathies have a genetic basis, a healthy lifestyle and constant mental activity can help delay disease onset and progression.
Follow-up
Taupathia is not curable and affects the life expectancy of those affected. Therefore, follow-up care for this disease is limited. Early detection is of great importance for the further course. The intake and dosage of medications as well as the course of the disease should be monitored by the physician to be treated. Possible side effects of the medication as well as new symptoms can be treated more quickly. The probability of developing pneumonia is increased in patients. This can be counteracted by taking precautions to maintain the health of the lungs, such as regular flu vaccinations. As physical impairments occur, nursing assistance is needed for daily living. In some cases, patients also require a wheelchair. Physiotherapy can also lead to an improvement or slowed progression of the impairment of movement. If possible, sports activities during leisure time are positive for body and mind. However, the type of sport and intensity should be clarified with a doctor beforehand. With the physical impairments, there are usually also psychological problems such as depression. Psychological counseling and integration into family life are important for the person affected. Friends also play a major role so that the patient is not alone with his situation and can cope with it better.
What you can do yourself
Tauopathies cannot yet be treated causally. Affected individuals are best advised to consult a neurologist so that he or she can initiate appropriate measures. Symptomatic treatment should be done in collaboration with a specialist. In the case of symptoms such as loss of appetite or bedriddenness, medical treatment is necessary. Those affected are usually already so severely ill that they can no longer act independently. This makes the help of relatives all the more important, as they must ensure that the medication is taken as prescribed and that the patient does not otherwise show any other signs of illness. In order to avoid sores when the patient is bedridden, he or she must regularly change position or be moved to a different position. In addition, various wound ointments from homeopathy can be used. Close relatives often need therapeutic support themselves as well. Particularly in the final stage of the disease, those affected are usually no longer able to recognize their acquaintances, which represents an enormous emotional burden for them. Since most tauopathies are genetically determined, prevention is also not possible. However, a healthy lifestyle and regular mental training can delay the disease. Which measures are useful and necessary in detail is best discussed with the relevant specialist.
