60 Hereditary and Acquired Sideroblastic Anemias

Question 1

Normal red cell precursors have cytoplasmic organelles that contain aggregated iron-rich
ferritin termed

Answer 1

Siderosomes

Question 2

These aggregates may be below the resolution of the light microscope hence stained with

Answer 2

Prussian blue

About 20% to 40% of red cell precursors have one to three very small, pinhead-sized blue granules in the cytoplasm

Relatively insensitive method to identify these structures

Question 3

Pathologic sideroblasts are of two types:

Answer 3

• Ring sideroblast : large, Prussian blue–
  stained granules in a circumferential position around the nucleus of the erythroblast (intramitochondrial location)
• Sideroblast with large and multiple cytoplasmic granules

Question 4

Ring sideroblasts are erythroblasts characterized by at least five siderotic granules surrounding at least ___________ of the nuclear circumference

Answer 4

One-third

Question 5

Sideroblastic anemias are characterized by:

Answer 5

• Hypochromic and normochromic erythrocytes in the blood film (dimorphic picture)
• Increased red cell precursors in the marrow in the face of anemia and a low reticulocyte count.
• Anemia that is the result of apoptosis of late erythroid precursors (ie, ineffective erythropoiesis), with increased plasma iron turnover and normal to decreased red cell survival.

Question 6

Drugs that___________________ decrease heme synthesis and can cause sideroblastic anemia.

Answer 6

Reduce the formation of pyridoxal 5′ phosphate from pyridoxine

B6

Question 7

Mutations of ____________, a splicing factor gene, are closely associated with ring sideroblasts.

Answer 7

SF3B1

Question 8

Secondary sideroblastic anemia is most commonly associated with use of

Answer 8

• Isonicotinic acid hydrazide
• Pyrazinamide
• Cycloserine

Question 9

Mineral deficiency that cause similar hematologic picture as sideroblastic anemia

Answer 9

Copper Deficiency and Zinc-Induced Copper Deficiency

Question 10

A mitochondrial deletion type of hereditary sideroblastic anemia causes

A refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreatic dysfunction

Answer 10

Pearson marrow-pancreas syndrome

May be fatal in infancy or early childhood and is characterized by marrow failure with macrocytic sideroblastic anemia, which is typically transfusion dependent

Question 11

Patients with hereditary sideroblastic anemia may respond to

Answer 11

Pyridoxine

Oral doses of 50 to 200 mg daily

Folic acid administered concomitantly may increase the response.

Question 12

HSPA9 is one of the genes in the 5′ region in the acquired 5q deletion of myelodysplastic syndrome coined:

Characterized by a defect in erythroid maturation, but ring sideroblasts are uncommon

Seen in Congenital sideroblastic anemias

Answer 12

5q minus syndrome

Question 13

A distinct form of X-linked sideroblastic anemia, associated with ataxia (XLSA/A),
was mapped to chromosome region Xq13 and results from mutations of the:

Answer 13

Adenosine triphosphate (ATP)-binding cassette (ABCB7 gene)

Question 14

Hereditary X-linked sideroblastic anemias (XLSA) patients have mutations in the

Answer 14

ALAS2 gene