Neonatal congenital leukemia caused by several missense mutations and AFF1-KMT2A fusion: A case report

Neonatal leukemia, a congenital form of leukemia, is a rare and fatal disease occurring in the neonatal period. Its etiology and pathogenesis have remained to be fully elucidated and the clinical manifestations differ due to age variability. Acute myeloid leukemia (AML) occurring after birth indicates genetic abnormalities and possibly intrauterine exposure to radiation, drugs or other toxins. The present report described the case of a premature neonate without phenotypic signs of Down syndrome, but with an elevated white blood cell count, mainly pertaining to the monocytes of peripheral blood. At 31 weeks of gestation, delivery by Caesarean section was performed due to fetal distress; however, the infant died three days after birth. Further laboratory examination indicated pediatric myeloid leukemia. The present case report described a case of fetal AML. According to the results of peripheral blood smear and targeted-panel sequencing, 5 missense mutations with clinical significance and a novel AFF1-KMT2A fusion gene were detected, which may be the main causes of AML and death.