Frameshift variance in SLC19A2 gene causing thiamine responsive megaloblastic anemia (TRMA): a case report from Pakistan

Thiamine responsive megaloblastic anemia syndrome is a rare genetic disorder usually associated with sensorineural deafness, megaloblastic anemia, and/or diabetes mellitus due to mutations in SLC19A2, encoding a thiamine transporter protein. In this case, we report a 2.5-year-old baby boy born to consanguineous parents. He was noted to be deaf and mute during his first year of life. He was diagnosed with anemia at the age of 15 months and required blood transfusion twice. The cause of anemia was not established and it was attributed secondary to some viral infection. At the age of 2 years, he was diagnosed with DM. The diagnosis of TRMA had been made during his evaluations for uncontrolled blood glucose, sensorineural deafness, and anemia. After few weeks of thiamine replacement, his hemoglobin increased to normal values; his sugars improved but had no changes in his deafness. Analysis of all coding regions and exon/intron boundaries of the SLC19A2 gene by Sanger sequencing. A p,Leu208fs homozygous frame shift variant is identified in the SLC19A2 gene, located on the Exon 2 and DNA description is c.623dup. This variant is predicted to be pathogenic and diagnosis of TRMA syndrome is confirmed. The diagnosis of TRMA should be kept in mind in differential diagnosis of DM with anemia and or sensorineural hearing loss. Particularly in the populations where the consanguinity is frequent as diagnosis has great impact on management.