Abstract
Relevance: Infant leukemia is defined as a condition in which leukemic cells are detected at birth or within the first months of life. Although from cytological and histological perspectives, acute leukemia in infants resembles forms observed in older children and adults, it is distinguished by specific clinical and genetic features. The clinical course of infant leukemia is typically marked by rapid onset, a high leukocyte burden, frequent extramedullary manifestations -including involvement of the central nervous system, liver, and spleen – and a high risk of early complications. The study aimed to assess the clinical features and early diagnostic characteristics of infant leukemia in children under one year of age in the Republic of Kazakhstan. Materials and Methods: This retrospective study included 16 infants (<1 year of age) diagnosed with acute leukemia and treated at the Scientific Center of Pediatrics and Pediatric Surgery, Almaty, Republic of Kazakhstan, between 2018 and 2023. Results: Genetic and congenital disorders were identified in children with infant leukemia. Down syndrome was diagnosed in 18.8% of patients (3/16), and trisomy 8 and intrauterine infection were each identified in one patient. Morphological analysis revealed a predominance of acute lymphoblastic leukemia (75%), while acute myeloblastic leukemia accounted for 25% of cases. In our study, rearrangements in the Mixed Lineage Leukemia (KMT2A, 11q23) gene were detected in approximately 91% of cases. The most frequent translocation was t(4;11)(q21;q23), observed in 30% of patients. Conclusion: The identified cytogenetic and immunological features, including the high prevalence of the t(4;11) translocation, are associated with an unfavorable prognosis, primary resistance to therapy, and a high risk of early relapse. These findings underscore the need for early molecular genetic and immunophenotypic profiling, as well as the development and implementation of risk-adapted therapeutic strategies for infants with acute leukemia.