The essential features of X-linked sideroblastic anemia include the following: (1) a hypochromic microcytic anemia and 2 discrete populations of red blood cells, one microcytic and the other normocytic; (2) marrow ringed sideroblasts, particularly prominent in the late erythroid precursors; (3) a variable hematologic response to pharmacologic doses of pyridoxine; and (4) systemic iron overload secondary to chronic ineffective erythropoiesis. The age of clinical onset of the disorder can vary from in utero to the ninth decade. Whereas males are preferentially affected, females may present with clinically severe anemia. More commonly, female carriers of the disease have an increased red blood cell distribution width and sometimes erythrocyte dimorphism (Fleming, 2002).
Genetic Heterogeneity of Sideroblastic Anemia
See also SIDBA2 (205950), caused by mutation in the SLC25A38 gene (610819) on chromosome 3p22; SIDBA3 (616860), caused by mutation in the GLRX5 gene (609588) on chromosome 14q32; SIDBA4 (182170), caused by mutation in the HSPA9 gene (600548) on chromosome 5q31; and SIDBA5 (619523), caused by mutation in the HSCB gene (608142) on chromosome 22q12. [from
OMIM]