Sideroblastic Anemias

GENERAL PRINCIPLES

Definition

Sideroblastic anemias are hereditary or acquired RBC disorders characterized by abnormal iron metabolism associated with the presence of ring sideroblasts (RS) in the developing RBCs in the BM.

Etiology

• Acquired

î Primary sideroblastic anemia (myelodysplastic syndrome with ring sideroblasts [MDS-RS] or myelodysplastic/myeloproliferative neoplasms with ring sideroblasts [MDS/MPN-RS]).

î Secondary sideroblastic anemia is caused by drugs (i.e., chloramphenicol, cycloserine, ethanol, isoniazid, pyrazinamide), lead or zinc toxicity, chronic alcohol use, or copper deficiency.

• Hereditary

î X-linked

î Autosomal

î Mitochondrial

DIAGNOSIS

A BM examination including cytogenetics is needed to evaluate for the presence of RS or other abnormal marrow forms. MDS-RS and MDS/MPN-RS are often associated with mutations in SF3B1.

TREATMENT

• Remove any possible offending agent.

• Replete copper deficiency.

• Pyridoxine 50-200 mg daily may be effective to treat hereditary sideroblastic anemias.

• Luspatercept is approved for treatment of anemia in patients with MDS-RS or MDS/MPN-RS.⁵