A new mutation responsible for genetic neurological disorder spinocerebellar ataxia (SCA) has been revealed in a new study published in Molecular Brain.
Genetic disease spinocerebellar ataxia (SCA) is characterised by a degeneration of the cerebellum, the part of the brain involved in the control of voluntary muscle movement like walking and speaking. It is brought about by a series of mutations, many of which are still a mystery to scientists — mutations accounting for 30% of the cases are as yet unknown. However, scientists are investing much into finding out the causes of the disease, and a team from Hiroshima University has found a new mutation.
The researchers obtained their data from two families with three generations of SCA. When they were tested for the disease at hospitals, no known genetic mutation was found. It was then that Hiroshima University scientists analysed their genetic samples to look for the new mutation.
The DNA of 4 family members was sequenced, and compared with that of unrelated individuals not suffering from SCA. This method allowed for the identification of the genetic variation shared among family members with SCA which were otherwise absent in healthy people.
The guilty gene, known as CACNA1G, was found on chromosome 17 for both the families. It encodes for Cav3.1 protein which constitutes an ion channel mediating the movement of calcium ions into nerve cells through an electrical impulse sent to the brain. The protein has never been correlated with SCA before.
Mutation in the CACNA1G characterised by modification in its DNA sequence leads to a mutated Cav3.1 channel which only opens at a lower threshold, thereby affecting the movement of calcium into cells.
These findings undoubtedly provide invaluable information for treating the disease. Lead author of the study, Professor Hideshi Kawakami, explains that patients of SCA might potentially be cured by concocting a drug targeting the calcium channel.
Also, skin cells taken from a patient were used to grow this individual’s neurones in laboratory by using induced pluripotent stem cell experimenting. The new neurones displayed no physical change, deformities, that are seen in the normal progression of SCA. This means that some patients of the disease will not show symptoms until middle-age because of the type of mutation they have.