Spinocerebellar ataxia

Spinocerebellar ataxias ( spinocerebellar ataxias in English, named SCA) are a large group of clinically similar neurodegenerative diseases in humans.

Description

The spinocerebellar ataxias occur at a frequency of one per 100,000 people sick. In individuals affected to first symptoms usually in middle age by movement disorders, unusual eye movements, decreasing sense of and decreasing perception show. In the course of the symptoms intensify, leading to subcortical dementia, and ultimately death.

Pathologically the disease accompanied a loss of Purkinje cells, the largest neurons of the cerebellum ( cerebellum). At the genetic level, the group of spinocerebellar ataxia is very heterogeneous, 26 loci, there are already described in the scientific literature and in accordance with the order of their discovery with SCA1 to SCA26 designated (as of 6/2005 ). However, the exact mutation or their precise location is not yet known for all diseases.

The long been known SCA types 1, 2, 6, 7, and 17 are expected to be the group of Trinukleotiderkrankungen such as Huntington's, spinobulbar muscular atrophy type Kennedy ( SBMA ) and Dentatorubro - Pallidoluysische atrophy ( DRPLA ), as the disease-causing mutation, an unusually long triplet repeat of the codon CAG ( corresponding to the amino acid glutamine) is. You together is furthermore an autosomal dominant mode of inheritance and the fact that the CAG repeat in the rule extended with each generation. The biological function of the proteins encoded by these genes proteins (called ataxin 1, 2, 3, 6, 7, and TBP ( in SCA17 ) ) is largely unclear. It do not encode all affected SCA genes for proteins. The SCA8 gene encodes for example, an antisense RNA, which, scientifically speaking, initially led to great confusion, as were aberrant Proteinagglomerate as disease-inducing at this time.

Research on SCAs has been greatly intensified in recent years, but it is not yet so far advanced at the moment that patients can expect in the near future with a curative therapy.

Machado - Joseph disease

The spinocerebellar ataxia 3 ( SCA3 ) is referred to in the literature mostly as Machado - Joseph disease ( MJD ). The cause of the disease is a mutation of the gene on chromosome 14 MJD1 locus Q24.3 - 32.1, which leads to a prolongation of the polyglutamine region. With a share of 35% of autosomal dominant cerebellar ataxias, the MJD is the most common form of this disease in Germany.

SCA13

Main article spinocerebellar ataxia type 13

Spinocerebellar ataxia type 13 ( SCA13 ) is a neurodegenerative disease that affects the cerebellum ( cerebellum ). SCA13 is an autosomal dominant.

SCA13 is caused by mutations in the potassium channel KCNC3 ( Kv3.3 ). So far, three mutations have been observed: R420H, R423H and F448L. R420H mutations are associated with disease in adulthood, the other with childhood disease or congenital and slower progression.