Abstract: Objective　To explore the genetic changes, clinical manifestations, diagnosis and treatment of congenital sideroblastic anemia in infants. Method　The clinical data of congenital sideroblastic anemia in a child were retrospectively analyzed. Results　A 5-month-old boy visited for pale complexion. Laboratory examination showed microcytic hypochromic anemia with serum iron of 58.30 μmol/L. Iron staining of bone marrow smears showed the outer iron was +++, and the inner iron accounted for 76%, of which the ring iron was 54%. High-throughput sequencing showed that the ALAS2 gene has a hemizygote mutation, C.1565C > A, which was predicted a harmful mutation by bioinformatics software and may affect the function of proteins. The mother of the child had a heterozygous mutation, which belonged to X-linked recessive inheritance. Literature was reviewed and no report was found. The child was clinically diagnosed with congenital sideroblastic anemia and was effectively treated with vitamin B6. Conclusion　Congenital sideroblastic anemia is rare, and a novel hemizygous mutation in the ALAS2 gene has been found.

Key words: anemia; hereditary; small cell low pigment; sideroblastic