Here is a description of a few different forms of the best known cerebellar ataxias.

Hereditary ataxias are diseases of the central nervous system. The ataxia is generally the consequence of a cerebellar affliction which can affect the cerebellum itself or the fibres which conduct information and of which the transmission is done by the spinal chord (spinocerebellar tract). These diseases are genetic, evolutive and for the moment without cure.

Genetic disease

The genes of ataxias are found on a chromosome and contain all the information for the building of a protein (containing amino acids) which is situated in the interior of the mitochondria.

Mitochondria are small corpuscles present in great numbers in the cells of the organism which have as their role to produce chemical energy coupled with the consummation of oxygen. Mitochondria contain enzymes accelerating the reactions of transferring food into energy.

Hereditary ataxias are a group of mitochondrial diseases characterized by processes of dysfunction of the mitochondria in the skeletal muscles. This brings about a progressive disease in the production of energy in the cell. When these dysfunctions repeat themselves on a large scale in the body, entire systems (nervous system, sensory system, etc.) begin to fail.

The severity of these diseases will in fact depend on the organs which are the most affected by the dysfunction of the mitochondria.

Modes of transmission

Recessive: Both parents must be carriers in order for a child to be afflicted. The parents are in good health. According to the law of genetics, 25% of the children will be afflicted.

 

Autosomal recessive transmission mode

Dominant: Only one parent who is a carrier is necessary in order that the child be afflicted.

 

Autosomal dominant transmission mode