Thiamine responsive megaloblastic anemia (TRMA), or Rogers syndrome, is a rare autosomal recessive disease characterized by the development of megaloblastic anemia, diabetes mellitus, and progressive sensorineural hearing loss. In some cases, the syndrome causes ophthalmological disorders (retinitis pigmentosa, optic nerve atrophy, maculopathy, nystagmus), heart diseases (paroxysmal atrial fibrillation, supraventricular tachycardia, congenital heart defects, intracardiac conduction disorders) and neurological disorders (epilepsy, cerebrovascular accidents). TRMA develops due to a mutation in the SLC19A2 gene, which encodes ThTr-1 (thiamine transporter protein) expressed in hematopoietic stem cells, pancreatic beta cells, and inner ear cells. The article presents a clinical case of TRMA in a three-year-old child, with the onset in the first year of life, manifesting as anemia and diabetes mellitus. Thiamine therapy ensured a pronounced positive dynamics: the patient's peripheral blood parameters normalized. The clinical description and the literature review herein aim to raise awareness of doctors of all specialties about this syndrome. An atypical clinical picture and lack of knowledge about TRMA often delay the diagnosis and start of therapy.