What are the genetic changes related to biotin-thiamine-responsive basal ganglia disease ?
Biotin-thiamine-responsive basal ganglia disease is caused by mutations in the SLC19A3 gene. This gene provides instructions for making a protein called a thiamine transporter, which moves thiamine into cells. Thiamine, also known as vitamin B1, is obtained from the diet and is necessary for proper functioning of the nervous system.  Mutations in the SLC19A3 gene likely result in a protein with impaired ability to transport thiamine into cells, resulting in decreased absorption of the vitamin and leading to neurological dysfunction. In this disorder, abnormalities affect several parts of the brain. Using medical imaging, generalized swelling as well as specific areas of damage (lesions) in the brain can often be seen, including in the basal ganglia. The relationship between these specific brain abnormalities and the abnormal thiamine transporter is unknown.  It is unclear how biotin is related to this disorder. Some researchers suggest that the excess biotin given along with thiamine as treatment for the disorder may increase the amount of thiamine transporter that is produced, partially compensating for the impaired efficiency of the abnormal protein. Others propose that biotin transporter proteins may interact with thiamine transporters in such a way that biotin levels influence the course of the disease.