Is Alzheimer's disease inherited, is it genetic, is it contagious?

Alzheimer's disease

is a chronic, progressive disease that impairs memory, thinking and movement. Some studies show that a person is at increased risk of developing Alzheimer's disease if they have a relative with the disorder.

Alzheimer's disease

is the most common cause of dementia and can seriously affect a person's ability to think, make judgments and carry out everyday tasks. Doctors have known about Alzheimer's disease for years, but many aspects of the condition and possible treatments remain unknown. The causes of Alzheimer's disease are unclear. Modern research shows that many factors can contribute to the development of Alzheimer's disease, one of which is genetics or heredity.

Is Alzheimer's disease inherited?

Scientists describe genetic risks for Alzheimer's disease in terms of two factors: risk genes and determinant genes.

When a person has risk genes, it means they are more likely to develop the disease. For example, a woman with the BRCA1 and BRCA2 genes has a higher risk of developing breast cancer.

Determined genes can directly cause the development of the disease.

Scientists have discovered several risk and deterministic genes for Alzheimer's disease.

Transmission routes

Genetics is developing at an increasingly rapid pace, and there is every reason to assert that a gene, as a fragment of DNA, is indeed a carrier of hereditary characteristics, but transmitted not in exact form, but in the state of mosaic particles.

This means that under the influence of various factors that form memory loss and decreased mental abilities, only a small part of the genetic material that carries a tendency to develop dementia can be passed on to the descendant .

If a descendant is concerned with the health of the body and mind, then diseased genes may well undergo changes and lose the lion's share of their impact, that is, correction of inherited genes is possible.

Gene differences are divided into two main types:

1. Variation (not carrying pathologies).
2. Mutated (changed, capable of harm).

Dementia can develop under the influence of both types of genes, and it is enough that just one gene was mutated for a person to be doomed to a certain disease, and this is not always dementia.
What else you need to know about Alzheimer's disease:

• is there a difference in the manifestations of the disease in young and old people, in representatives of different sexes;
• what is the patient’s life expectancy and does he need care;
• what is the treatment, what methods and drugs are used;
• How to prevent the development of the disease in yourself and your loved ones.

Risk genes

Several genes pose a risk for developing Alzheimer's disease. The gene with the most significant association with Alzheimer's disease is the apolipoprotein E-e4 (APOE-e4) gene. About 20-25% of people with this gene may suffer from Alzheimer's disease. A person who inherited the APOE-e4 gene from both parents has a higher risk of developing Alzheimer's disease than a person who inherited the gene from only one. Having the gene may mean that a person exhibits symptoms at an earlier age and is diagnosed earlier. Other genes may influence late-stage Alzheimer's disease and its progression. Scientists need to do more research to find out how these genes increase the risk of developing Alzheimer's disease.

Some of these genes regulate certain factors in the brain, such as inflammation and the way nerve cells communicate. While everyone inherits the APOE gene in some form, the APOE-e3 and APOE-e2 genes have no connection with Alzheimer's disease. APOE-e2 may even have a protective effect on the brain against the disease.

Alzheimer's treatment

To date, there are no available methods that would help cure degenerative brain damage. It is also impossible to slow down the course of the disease for a long period. All methods of therapy are palliative and are aimed only at alleviating symptoms. Therefore, drugs used for Alzheimer's disease can be divided into groups: those that slow down the process of deposition of beta-amyloid plaques, restore and protect brain cells and help improve the patient's quality of life.

The effectiveness of treatment depends on the duration of medication use. Some feel better after just a few uses, while others need to take several courses of medication.

Drug treatment

The effectiveness of drug treatment is on average 70%. But a more important indicator is the body’s individual reaction to the medication. To obtain the best treatment result, the doctor will select a therapeutic regimen personally. In order to objectively evaluate the therapeutic effect of the drug, it must be taken continuously for at least 3 months.

In clinical practice for the treatment of Alzheimer's disease, drug regimens are used, including cholinesterase inhibitors and memantine. There is a moderate effect of these drugs in early and moderate dementia.

Anticholinesterase drugs or cholinesterase inhibitors

New drugs used in the treatment of Alzheimer's are cholinesterase inhibitors. These drugs stop the activity of cholinesterase. The expected effect from them is improved memory. Prescription of medications of this pharmacological group is carried out only by the attending physician. They have contraindications and can cause side effects.

Memantine against Alzheimer's

Memantine is the only drug recommended by the world medical community for the treatment of Alzheimer's disease in severe dementia. This neurotropic drug is a derivative of amantadine. It has a neuroprotective effect and inhibits the progression of neurodegenerative processes. Taking it improves memory, increases the ability to concentrate, reduces fatigue, and reduces symptoms of depression.

This drug is contraindicated for epilepsy and severe renal impairment. The drug Memantine has satisfactory tolerability. To prevent stimulation of the central nervous system, it is recommended to take it in the first half of the day.

It has been clinically proven that regular use of the drug for 12 weeks leads to significant improvements in cognitive function, relieves acute behavioral symptoms and increases the ability to self-care.

Tranquilizers, neuroleptics, anticonvulsants

These groups of drugs are designed to relieve behavioral and psychotic symptoms of the disease. Antipsychotic drugs are most often used. But their use increases the risk of developing extrapyramidal symptoms - this is a complex of motor disorders of a neurological nature, such as parkinsonism syndrome, tremors, tics, convulsions, dystonia, chorea (involuntary sweeping movements). Therefore, antipsychotics are used only for severe behavioral disorders, and only drugs without anticholinergic effects are used. Tricyclic antidepressants are contraindicated for Alzheimer's disease.

Nootropics and tissue regeneration stimulators

Nootropic drugs are designed to improve intracellular metabolism in neurons. They prevent their damage and stimulate interneuron connections. Stimulators of tissue regeneration affect the cause of degenerative changes.

Psychotherapy

Psychotherapeutic methods can help patients with Alzheimer's disease overcome feelings of anger and anxiety. The psychotherapist will work with the patient, as a result of which he will be able to understand his feelings. If necessary, the doctor will prescribe medications. Psychotherapy methods are aimed at reducing anxiety and aggressiveness and improving thinking. They are not intended to improve clinical performance. In addition, psychotherapy methods are effective only at the initial stage of the disease. At more severe stages, their use does not make sense.

Art therapy for Alzheimer's patients

Art therapy as a method of psychological correction is used to combat neuroses and behavioral disorders. These are precisely the manifestations that are characteristic of patients with Alzheimer's disease. This method of treatment involves involving patients in various types of art to harmonize their mental state. Thus, through dancing, painting, music or literary creativity, abilities for self-knowledge and self-expression develop.

Art therapy for Alzheimer's disease in the following patient conditions:

• Depression and stress;
• Emotional instability;
• Emotional rejection;
• Feeling of loneliness;
• Anxiety;
• Aggressiveness.

Through commitment to art, an outlet for aggression and other negative feelings is created. Art therapy is used as an auxiliary method of treatment.

Sensory room

A sensory room is about organizing the environment in a special way. It is filled with various stimulants that affect the senses. A calming and relaxing effect is achieved through various combinations of stimuli, such as music, light, sounds, color, smells, and tactile sensations.

Classes in the sensory room for Alzheimer's disease will help with such psychological disorders as:

• neurosis;
• maladjustment;
• depression and psycho-emotional stress;
• weakening of sensory functions;

Memory Therapy

Used in late stages of the disease. This is an emotionally focused psychotherapy and it focuses on pleasant memories and happy thoughts. Using videos and photographs, as well as other items from the past, the therapist demonstrates and discusses positive memories experienced in the past. This helps to lift the patient out of depression, which has a positive effect on overall well-being, appearance and volitional functions.

Presence Stimulation

This method implies that recordings with the voices of close relatives will be played in the presence of the patient. Typically, this psychotherapeutic method is used for people with severe dementia when they are in a state of heightened emotional arousal and anxiety.

Sensory Integration

The sensory integration method involves stimulating the functioning of the senses through the coordination of various sensory systems. the purpose of its use is to stimulate the central nervous system. The senses are engaged through various exercises.

Nutrition

Patients with severe Alzheimer's are unable to control their food intake. Therefore, they often have an exhausted body and lack vitamins, nutrients and minerals.

At the beginning of the disease there are no problems with eating food. Then the patient’s diet does not differ from the classic diet of proper nutrition. Patients have no dietary restrictions. Lean protein, complex carbohydrates, unsaturated fats, vitamins and minerals are recommended for Alzheimer's patients. Their diet should consist of the following products:

• Turkey and fish;
• Broccoli;
• Spinach;
• Nuts;
• Beans;
• Pasta from durum wheat;
• Legumes;
• Cereals (millet, buckwheat);
• Whole wheat bread;
• Green vegetables;
• Olive oil;
• Seaweed;
• Fruits of all colors.

An Alzheimer's patient must follow a drinking regime and drink the required amount of clean water. When dehydrated, the death of neurons in the brain increases.

You cannot force a patient to eat when he refuses or is in an unfavorable mood. To prevent burns and injuries, food should not be too hot. Number of meals - 4-5 times.

Determined genes

Researchers have identified three specific deterministic genes that may cause Alzheimer's disease:

• amyloid beta precursor (APP)
• presenilin-1 (PS-1)
• presenilin-2 (PS-2)

These genes are responsible for excessive accumulation of amyloid beta peptide, a toxic protein that accumulates in the brain and causes nerve cell damage that is characteristic of Alzheimer's disease. However, not all people with early-onset Alzheimer's disease have these genes. A person with these genes who develops Alzheimer's disease has a rare type known as familial Alzheimer's disorder. Familial Alzheimer's disease accounts for less than 5% of all cases worldwide. Alzheimer's disease, caused by genetic determinants, usually occurs before age 65. Sometimes it can develop in people aged 40-50 years.

Late stage: severe dementia

The last stage of Alzheimer's disease is manifested by the complete inability of a person to exist without care, since his activity can only be expressed by screams and obsessive movements. The patient does not recognize relatives and friends, is inadequate in the presence of strangers, loses the ability to move and, as a rule, is bedridden.

The patient at this stage is usually not only unable to control the processes of emptying, but even loses swallowing skills.

But the patient dies not from Alzheimer’s disease itself, but from exhaustion, infections or pneumonia that accompany this pathology.

Gene influence on other types of dementia

Some types of dementia are associated with other genetic defects.

Huntington's disease

, for example, is caused by a change in chromosome 4, which can manifest as progressive dementia. Huntington's disease is a dominant genetic disorder. This means that if one parent has the disease, they can pass the gene on to their offspring and they will develop the disease. Symptoms of Huntington's disease usually do not appear until age 30 to 50. This can make it difficult for doctors to predict and diagnose before a person has children and passes on the gene.

Researchers believe that Lewy body dementia, or Parkinson's disease dementia, may also have a genetic component. However, they believe that other factors not related to genetics may also play a role in the development of these conditions.

Main symptoms of the disease

This disease was first described by the German psychiatrist Alois Alzheimer back in 1907.

The disease develops gradually, and affected people regretfully note that they have senile insanity. No one notices the progressive development of the problem: neither the affected person nor his relatives. Forgetfulness is an integral part of the life of an elderly person, but it is not always associated specifically with Alzheimer's disease.

Clinical manifestations of Alzheimer's disease progress gradually, slowly growing and increasing in strength, brain cells begin to die in increased volumes. This explains memory loss and the appearance of absent-mindedness and lack of coordination. Over time, the symptoms that appear lead to complete dementia.

At an early stage of development of the disease, the following symptoms are detected:

Alzheimer's disease

1. Changeability in mood, sudden aggression, increased irritability.
2. Decreased motor activity and decreased interest in current events and the world around them.
3. Absence of memories that happened 1 hour ago, yesterday or several years ago.
4. The problem of perceiving a conversation with an interlocutor, the lack of thinking processes and comprehension of what was said or heard, the impossibility of forming an adequate answer to the question posed.
5. Decreased functions of the patient's body.

In most cases, the first signs go unnoticed. They are attributed to the fatigue or inattention of an old person. But negative processes in the head gain momentum during this period.

Strong signs begin to manifest themselves at a time when a significant part of the brain cells are already destroyed. As a result, in addition to the initial symptoms, the following signs may appear:

• Loss of coordination in space and time (disorientation)
• The problem is recognizing familiar and important things
• Depression, uncontrollable anxiety, feeling of fear
• Apathetic mood, complete indifference
• The occurrence of hallucinations, delusional ideas
• Loss of ability to move independently or care for oneself
• Upright walking gives way to a shuffling gait
• Limb spasms may occur (in rare situations)

Symptoms of Alzheimer's disease can be aggravated by the patient being completely alone, abnormal heat or extreme cold in the room where the person lives. Negative processes can be triggered by unfamiliar things or household items, as well as large crowds of both familiar and unfamiliar people.

In addition, the cause of the problem moving from a moderate degree to a more severe one can be stimulated by the uncontrolled administration of medications or the occurrence of an inflammatory process through human infection.

Risk factors for developing Alzheimer's disease

Researchers have identified several risk factors for developing Alzheimer's disease. These include:

Age

: The most significant risk factor for developing Alzheimer's disease is age. People over 65 are more likely to develop Alzheimer's disease than younger people. By age 85, 1 in 3 people have this condition.

Family history

: Having a close relative with Alzheimer's disease increases your risk of developing it.

Head injury

: People with a history of severe head trauma, such as from a car accident or contact sports, are at higher risk of developing Alzheimer's disease.

Heart Health

: Cardiovascular health problems may increase your chance of developing Alzheimer's disease. Examples include high blood pressure, ischemic stroke, diabetes, heart disease and high cholesterol. The conditions listed above can damage blood vessels in the brain, which affects the risk of developing Alzheimer's disease.

Stages of Alzheimer's disease

Senile dementia or Alzheimer's disease goes through several stages in its development: from imperceptible symptoms to complete degradation. Each stage is characterized by specific manifestations, but they all relate to memory impairment and cognitive functions.

Predementia

The stage of pre-dementia is characterized by the occurrence of subtle cognitive impairment. Often they are detected only with detailed neurocognitive testing. Typically, it takes 7-10 years from the onset of early signs of Alzheimer's disease to diagnosis. The main disorder during this period is memory impairment. Forgetfulness concerns recent events or information learned the day before. Also, the elderly experience significant difficulties when they need to remember new information.

In addition, in the stage of pre-dementia, executive functions suffer. Thus, it is difficult for the patient to concentrate on anything and plan future actions. Difficulties are also associated with abstract thinking; it is difficult to remember and remember the meanings of some words. All these phenomena are often attributed to age-related changes. In fact, they are caused by pathological changes in brain structures. Due to the fact that at the onset of Alzheimer's disease the symptoms are mild, predementia refers to the preclinical stage of the disease. After it, cognitive changes become more pronounced.

Early dementia

At this stage of Alzheimer's disease, the main manifestation of the disease is memory impairment. This sign is the basis for the assumption of the progression of degenerative processes in the brain. At the same time, different types of memory suffer in different ways. Short-term memory is most affected, episodic and procedural memory is less affected. The person can still remember some distant events from his life, and semantic and implicit memory is also preserved. Long-learned actions and skills are remembered. At the same time, the patient is no longer able to remember new information and forgets events of the recent past. This disorder is accompanied by agnosia, a disorder of perception.

Forgetfulness of current events gradually increases. This fact becomes obvious to others. The patient has difficulties in chronological and geographical orientation. There are obvious disorders of mental operations. Abstract thinking is significantly impaired, and the ability to judge, generalize, and compare is also affected.

Despite maintaining independent living and self-care skills, patients lose the ability to independently perform financial transactions or conduct correspondence. Alzheimer's disease is accompanied by disorders of higher cortical functions. Speech, optical-spatial activity and the ability to consistently perform related actions suffer. The rate of speech decreases, the vocabulary decreases, a person cannot fully express his thoughts orally or in writing. Such disorders at this stage of disease development are characterized by distinct severity. Nevertheless, the patient adequately operates with simple concepts.

Moderate dementia

The main clinical manifestations of the stage of moderate dementia:

• violation of time orientation;
• impairment of short-term memory with preservation of long-term memory;
• the patient fills memory gaps with fictitious stories;
• self-service skills are lost;
• clumsiness appears in movements, gait changes;
• involuntary bowel movements or urination;
• Personality disorders: aggressiveness, tearfulness, irritability, tendency to wander.

The progression of cognitive impairment significantly reduces a person's ability to perform independent actions. At this stage, speech disorders and agnosia (visual perception) clearly appear. It becomes difficult for a person to construct a phrase correctly. Often its meaning is lost because the patient forgets some words or uses them in the wrong context. Such speech disorders lead to dysgraphia and dyslexia. The first is the loss of writing skills, and the second is the loss of reading skills. A progressive praxis disorder deprives the patient of the ability to self-care, even basic skills are lost. Thus, a patient with Alzheimer’s at this stage cannot undress or dress independently, or eat food.

With moderate severity of senile dementia, a “shift of the situation into the past” is observed, in other words, memories of the long past are revived, and the people around him are perceived as persons from this past.

Severe dementia

Regardless of the type of disease, in the last stage of Alzheimer's, profound decay of memory, loss of concepts of time, amnesia and disorientation, delusional inferences and judgments, loss of ideas about one's own personality and psychomotor skills are observed.

The patient's speech consists of single words or individual phrases. Subsequently, speech skills are completely lost. At the same time, the ability to maintain emotional contact and perceive others remains for a long time.

The severe stage of dementia is accompanied by complete apathy. Aggressive attacks may occur. Mental and physical exhaustion of patients is observed. They become completely dependent on others. They move with difficulty and therefore rarely get out of bed. As a result of prolonged immobilization, muscle mass is lost, congestive pneumonia and bedsores develop. It is these complications that cause death.

The causes of Alzheimer's disease are not fully understood. Currently, there are more than 10 theories of the occurrence of this pathology. In Alzheimer's disease, the causes of neurodegenerative disorders are explained through 4 main hypotheses.

Cholinergic hypothesis

According to this theory, the pathology is provoked by a decrease in the production of the neurotransmitter acetylcholine. However, modern researchers have questioned this theory, since drug supplementation of this substance did not lead to an improvement in the patient’s condition.

Amyloid hypothesis

According to this theory, beta-amyloid deposition is the main cause of the disease. Beta-amyloid plaques are deposited on the outside and inside of neurons. As a result, the transmission of signals between neurons is disrupted, after which they die.

Tau hypothesis

According to it, the disease begins after deviations begin to occur in the structure of the tau protein. This is what leads to disruption of the functioning of brain cells. The affected neuron begins the process of combining strands of tau protein, which disrupts the biochemical transmission of signals between the tiles. After which the cells themselves die. A sequence of neurodegenerative changes is initiated following the accumulation of beta-amyloid.

Hereditary hypothesis

There is a genetic predisposition to Alzheimer's disease. So, if close relatives have this disease, family members have an increased risk of developing this pathology. Mutations on chromosomes 21, 19, 14, and 1 are thought to cause Alzheimer's disease. It is believed that genetic predisposition slightly increases the likelihood of developing the disease, but does not necessarily cause it.

Early signs of Alzheimer's disease

Alzheimer's disease is usually accompanied by a gradual loss of memory and brain function. Early symptoms may include periods of forgetfulness or memory loss. Over time, a person may experience confusion or disorientation in familiar environments, including at home.

Other symptoms may include:

• changes in mood or personality
• confusion about time and place
• difficulty with routine tasks such as doing laundry or cooking
• difficulty recognizing objects
• difficulty recognizing people

The aging process can naturally deteriorate a person's memory, but Alzheimer's disease leads to longer periods of forgetfulness.

Over time, a person with Alzheimer's disease may need more and more assistance with activities of daily living, such as brushing teeth, getting dressed, and eating. They may experience agitation, restlessness, personality disorders and speech problems. The life expectancy of a person with Alzheimer's disease is usually 8 to 10 years after the first symptoms of the disease appear.

Because people with advanced Alzheimer's disease are unable to care for themselves or may not understand the importance of food, common causes of death include malnutrition, malnutrition, or pneumonia.

Prognosis and life expectancy

The prognosis of the disease is unfavorable, since it is based on a progressive neurodegenerative process. It is possible to slow down the progression of the pathology and stabilize the patient’s condition for a limited period of time, no more than 3 years, with adequate and long-term therapy. However, the constantly progressive loss of essential body functions inevitably leads to death. How long people live with Alzheimer's disease at the last stage depends on the rate of death of brain neurons.

The average life expectancy of a patient after diagnosis is 7 years. Less than 3% of patients live longer than 14 years after diagnosis of the disease. The patient's life prognosis worsens due to the fact that Alzheimer's disease is difficult to diagnose in the early stages. Typically, the diagnosis is made when a person's daily activities are impaired by the development of cognitive impairment. But even then the patient remains capable of independent life. The prognosis is also complicated by concomitant pathologies, such as alcoholism, heart and vascular diseases, and diabetes.

When to see a doctor

Seeking medical help for a person who has these symptoms is vital. Your doctor can rule out other conditions that may cause dementia, such as a urinary tract infection or a brain tumor.

Family members should make a list of all medications the symptomatic person is currently taking. Your doctor can review the list to make sure your dementia symptoms are not side effects of medications.

Identifying noticeable symptoms and their progression can help the doctor identify potential patterns. Although genetic testing is available, doctors generally do not recommend it. Having the genes does not necessarily mean a person will have the condition, and testing may cause unnecessary anxiety and fear. However, a person with a family history of early Alzheimer's disease may wish to undergo genetic testing. Most doctors recommend meeting with a genetic counselor ahead of time to discuss the pros and cons of genetic testing and how they might interpret the results.

Sometimes a doctor may recommend genetic testing when a person exhibits early symptoms of Alzheimer's disease, as this may dictate possible treatments.

How to diagnose?

There are several methods - from simple to serious laboratory tests. It turns out to be difficult to do this on your own; often people who are fixated on various kinds of illnesses will find an ailment where there is none. To confirm the results, please consult your doctor.

• Tests. There are various questionnaires on the Internet and popular science magazines that allow you to give a subjective assessment of a person’s health from the point of view of the functioning of the central nervous system. The subject is asked to answer questions regarding the state of memory, interpersonal relationships with family, friends and strangers. After working on the questionnaire, you can look at the keys to the test. To ensure the reliability of the result, it is better to consult a doctor who will be able to distinguish true symptoms from fictitious ones;
• Magnetic resonance imaging. Examination of the brain makes it possible to see a complete picture of the functioning of the central nervous system. In addition to this procedure, the doctor prescribes a number of laboratory tests, which together give a holistic picture of the person’s health status.

It is not necessary to wait for obvious symptoms of the disease to appear. If you have any concerns, get examined as soon as possible. It is easier to prevent a disease and delay the onset of negative consequences than to deal with it in the later stages, when medications are powerless.

What therapeutic measures can cure AD in the future?

Effective drugs are being developed to treat Alzheimer's disease

Recent phase 3 immunotherapy studies have shown that an antibody that targets the N-terminal portion of amyloid-β prevents amyloid-β deposition in the brains of APOE ε4 carriers. Bapinezumab also reduces phosphorylated tau levels in the cerebrospinal fluid. Therefore, immunotherapy may be useful in eliminating beta-amyloid from the brains of AD patients.

The main side effects of bapinezumab, namely vasogenic cerebral edema and microhemorrhage, are more common in APOE ε4 carriers. Although bapinezumab failed to prevent cognitive and functional impairment in these clinical trials, combining Aβ immunotherapy and nootropics may lead to improved treatment outcomes.

The presence of a defective allele does not always lead to AD. This genetic isoform likely accelerates the onset and progression of the disease. However, geneticists' understanding of the potential pathogenic link between APOE ε4 and cognitive function may allow early identification of men, women, and children at increased risk of AD.

Hypothetical causes of the disease

As mentioned above, heredity only creates a favorable background for the onset and development of pathogenic changes.

What process leads to the death of neurons and the accumulation of plaques? There is no clear answer to this question.

There are three main hypotheses:

• amyloid - the disease occurs due to the deposition of amyloid beta (Aβ);
• cholinergic - due to a decrease in the synthesis of the neurotransmitter acetylcholine;
• tau hypothesis - the process is triggered by deviations in the structure of the tau protein.

The amyloid hypothesis has become most widespread and significant.

Its postulates have been repeatedly proven by its relationship with the genetic model.

Proponents of the concept believe that the accumulation of beta-amyloid consistently triggers the mechanisms of neurodegenerative processes, but does not in itself lead to pathology.

However, the true nature is not clear. It is only clear that years pass from the moment the accumulation begins until the critical point in the death of neurons is reached.