Thiamin-responsive megaloblastic anemia syndrome (TRMA) is characterized by diabetes mellitus, megaloblastic anemia and sensorineural deafness. Mutations in the thiamin transporter gene SLC19A2 cause TRMA. To generate a mouse model of TRMA, we developed an Slc19a2 targeting construct using transposon-mediated mutagenesis and disrupted the gene through homologous recombination in embryonic stem cells. Erythrocytes from Slcl9a2-/- mice lacked the high-affinity component of thiamin transport. On a thiamin-free diet, Slcl9a2-/- mice developed diabetes mellitus with reduced insulin secretion and an enhanced response to insulin. The diabetes mellitus resolved after 6 weeks of thiamin repletion. Auditory-evoked brainstem response thresholds were markedly elevated in Slc19a2-/- mice on a thiamin-free diet, but were normal in wild-type mice treated on that diet as well as thiamin-fed Slcl9a2-/- mice. Bone marrows from thiamin-deficient Slc19a2-/- mice were abnormal, with a megaloblastosis affecting the erythroid, myeloid and megakaryocyte lines. Thus, Slc19a2-/- mice have provided new insights into the TRMA disease pathogenesis and will provide a tool for studying the role of thiamin homeostasis in diabetes mellitus more broadly.
|Number of pages||10|
|Journal||Human Molecular Genetics|
|Publication status||Published - Nov 1 2002|
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