The diagnosis of thiamine-responsive megaloblastic anemia was confirmed by genetic testing, which detected compound heterozygous mutations in the SLC19A2 gene that included a pathogenic frameshift mutation (c.620_624dup; p.Pro209Phefs*21) and a missense variant (c.170 T > C; p.Leu57Pro). This evidence concerns the gene SLC19A2 and megaloblastic anemia.