The spinocerebellar ataxias are a group of genetic diseases characterized by degeneration of the cells that make up the cerebellum (which is the "command center" that controls balance and makes the body movements coordinated).
For this reason, the spinocerebellar ataxias have as a result alterations of strength, speed and dexterity of movement. The main signs are ataxia (staggering gait), dysmetria (difficulty in controlling the amplitude of movement); hypotonia (decreased muscle tone); difficulty in fixing his gaze. In many cases, unfortunately, these symptoms progress over time. There are several forms of spinocerebellar ataxias (which we abbreviate by the acronym SCA); from the clinical point of view the different forms are quite similar, so that often it is not easy to distinguish only on a clinical base. The distinction between the various forms of SCA is primarily genetically based. In fact, each of them is caused by the alteration of a different gene. A genetic test can diagnose exactly the type of SCA. Studies in recent years allowed us to identify the type of genetic alterations responsible for the appearance of the SCA.
The SCA are inherited with a mode called autosomal dominant. This means that the children of an affected subject have a 50% chance of developing the disease themselves, regardless of gender. A characteristic of SCA is that the symptoms and the age of onset of the disease are generally more severe and early with the passing of generations. The diagnosis on a clinical base hardly distinguishes between the different forms of SCA. For the identification is necessary to use a genetic test, through which it is possible to identify the expansion of trinucleotide which is the cause of the disease.