Thiamine Responsive Megaloblastic Anemia (TRMA) is an autosomal recessive disorder, characterized by the triad of megaloblastic anemia, sensorineural deafness, and diabetes mellitus. The anemia may be accompanied by mild thrombocytopenia, and/or leucopenia. In addition, some patients may also demonstrate congenital heart defects, stroke-like episodes and/or arrhythmias, and optic atrophy.
TRMA is caused due to mutations in the SLC19A2 (Solute Carrier Family 19, Member 2) gene. The product of this gene is a thiamine transporter, and mutations in this gene disrupt the active uptake of thiamine into cells. This deficiency of thiamine in the cells, in turn, leads to a loss of ribose synthesis within the cells, resulting in anemia.