Alzheimer’s is a neurodegenerative disease that produces progressive neuronal degeneration or death due to the deposition of protein waste called Amyloid and TAU in brain tissue, waste that is toxic and kills neurons. The disease was described as Early Dementia by Dr. Alois Alzheimer in Germany in 1906 and later both the early-onset dementia and the late-onset dementia that affects more than 40 million people in the world were called after his surname.

From the point of view of the age of onset, Alzheimer’s disease is classified into two types: early-onset Alzheimer’s when the symptoms of the disease begin before 65 years and late-onset Alzheimer’s when the symptoms begin after the patient is 65 years.

The autosomal dominant Alzheimer’s occurs before 65 years of age and is transmitted by one of the parents to approximately 50% of the children. There are 3 causal genes for Alzheimer’s disease: the gene for the amyloid precursor protein on chromosome 21, the gene for presynyl 1 on chromosome 14 and the gene for presenilin 2 on chromosome 1. When these genes are affected, the mutation produces the disease in a hereditary way. This autosomal dominant form of Alzheimer’s disease is only suffered by 1% of the world population with Alzheimer’s. Sporadic Alzheimer’s is the most common form worldwide and may be influenced by genetic susceptibility factors but not by genes of causality.

CADASIL is the English acronym to Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy, which describes the disease.

This means that it is a degenerative disease of genetic origin in which multiple infarctions occur in the smaller and deeper arteries of the brain (white matter) and that is hereditary in nature, which means, it is transmitted directly from parents to children, causing the probability that each child inherits it to be 50%.

It can manifest itself in several ways: from very intense headaches (migraines) and paralysis of some parts of the body to loss of memory and dementia.

The diagnosis is defined by the doctor based on the following requirements:

– Presence of symptoms such as paralysis of any part of the body, dementia or repeated thrombosis.

– Must belong to a family where several people have or have had any of these symptoms over several generations (hereditary character).

– If you have no symptoms but belong to a family with CADASIL, a radiological examination of the brain called Nuclear Magnetic Resonance of the brain could show the damage in the white matter before the first symptoms appear.

Ataxia is not a disease but a syndrome characterized by gait disorder, motor coordination and balance. People with ataxia walk like a drunk person. The ataxias are closely related to alterations of the cerebellum but also can be presented by systemic diseases. For example, the main and most common cause of ataxia is alcohol intoxication that produces gait disorders, balance disorders and dysarthria.

Most ataxias also produce dysarthria-type speech disorders or word articulation problems. Dysphagia, which means difficulty swallowing due to coordination problem of all the muscles involved in the process of swallowing food, can also occur. People with ataxia, in case of having swallowing problems, may have symptoms of choking when eating.

The ataxias can be symmetrical if they affect both sides of the body and asymmetric when the coordination problem occurs on only one side of the body. In these cases, it depends on which of the two cerebellar hemispheres is altered.

Ataxia can also affect the movements of the eyes producing what is now called ocular ataxia. Any injury that alters the functioning of the cerebellum can lead to ataxia, it could be it tumors, infections, vascular lesions or neurodegenerative lesions.

There is a very varied group of Ataxias that are produced by lesions of the cerebellum and the spinal cord that are due to genetic alterations and are hereditary, they are the Spinocerebellar Ataxias. Many types of them have been described and by different genes involved.

It is a degenerative neurological disease that produces movement disorders, behavioral disorders and dementia. It is also known as Huntington’s Chorea because of the involuntary movements produced by the disease. It was described by the American physician George Huntington in the year of 1872.

The cause of Huntington’s disease is an expansion of the CAG triplet in the Huntingtin gene that controls the protein of the same name. The huntingtin alterations cause cell death especially of the neurons of the basal ganglia of the brain that are in charge of the control of the movement.

For this reason, the disease usually begins with movement disorders expressed as choreic movements, facial grimaces, tics or athetoid movements. The disease is inherited in a Mendelian fashion with an autosomal dominant inheritance pattern. This means that the children of a person with HD have a 50% chance of suffering it.

It usually occurs in young adults between 35 and 55 years old. The disease occurs when there are more than 36 repeats of the CAG triplet. It can occur at younger ages in direct relation to the number of CAG triplets. When the number of triplets is higher, the disease becomes more precocious and aggressive.

It affects both men and women, without distinction of race or social class. There is no medication to cure this disease or stop its progression. The medical treatment available is palliative and seeks to improve symptoms and quality of life by trying to prolong autonomy and independence.

It is a neurodegenerative disease of slow evolution that affects the substantia nigra of the brain that has to do with the motor system and that manifests with tremor mainly at rest, rigidity and slowness to initiate movements. It was described in 1817 by James Parkinson. It affects 1% of the population over 65 years of age and less frequently to those under 40 years, in which case it is called Juvenile Parkinson’s.

There are 2 forms of hereditary Parkinson’s. The autosomal dominant form, which implies a risk of 50% transmission to children and the autosomal recessive form that implies a risk of 25% transmission to children. There are clinical pictures suggestive of Parkinson’s disease and are known as Parkinsonism. It is triggered by trauma, infection, tumor lesions, vascular lesions or ingestion of toxic substances or medications.

The cause of Parkinson’s disease, except for genetic forms, is unknown. It is known that there is a loss of nerve cells or neurons in a brain region called Substantia Nigra, responsible to produce a chemical known as Dopamine, a neurotransmitter involved in motor processes. Dopamine deficiency produces stiffness and tremor.