mutations in the "slc19a2" gene can cause thiamine-responsive megaloblastic anemia syndrome (trma), which is an autosomal recessive disease characterized by megaloblastic anemia, diabetes mellitus, and sensorineural deafness. onset is typically between infancy and adolescence, but all of the cardinal findings are often not present initially. the anemia, and sometimes the diabetes, improves with high doses of thiamine. other more variable features include optic atrophy, congenital heart defects, short stature, and stroke.