SLC19A3

At least seven mutations in the SLC19A3 gene have been identified in people with biotin-thiamine-responsive basal ganglia disease, a disorder that involves recurrent episodes of brain dysfunction (encephalopathy) and a variety of neurological problems that gradually get worse. SLC19A3 gene mutations 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. Using medical imaging, abnormalities can be seen in several parts of the brain, including a group of structures called the basal ganglia, which help control movement, but the relationship between these specific brain abnormalities and the abnormal thiamine transporter is unknown.

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SLC19A3 gene mutations have also been identified in individuals with other neurological disorders whose signs and symptoms overlap those of biotin-thiamine-responsive basal ganglia disease (described above). These include a disorder called early infantile lethal encephalopathy and another disorder that begins in early infancy and causes seizures and brain deterioration (atrophy). A small number of individuals with signs and symptoms similar to those of the neurological disorders Leigh syndrome and Wernicke encephalopathy have also been found to have SLC19A3 gene mutations. It is unclear why mutations in this gene cause varying signs and symptoms in different individuals.