Congenital nonspherocytic hemolytic anemia-9 (CNSHA9) is an X-linked hematologic disorder characterized by onset of mild to moderate red cell anemia soon after birth or in childhood. The anemia is associated with significantly increased activity of ADA (608958) specifically in erythrocyte precursors. ATP levels may be secondarily decreased. Additional features may include low birth weight, thrombocytopenia, hypospadias, and splenomegaly. Males are preferentially affected, although carrier females may show elevated erythrocyte ADA or mild features (Ludwig et al., 2022).