Question 1

Erythropoietic porphyrias are associated with:

Accepted Answer

Erythropoietic porphyrias are caused by mutations in the enzymes involved in the heme biosynthetic pathway, leading to the accumulation of porphyrin precursors and the development of symptoms such as skin photosensitivity, hemolytic anemia, and splenomegaly. Abnormal iron metabolism (A) may be seen in some types of porphyrias, but it is not specific to erythropoietic porphyrias. Abnormal globin synthesis (C) is not directly related to porphyrias. DMT1 mutations (D) are associated with iron metabolism disorders, but not with porphyrias.

Question 2

Criteria for the diagnosis of hemochromatosis in adult males include transferrin saturation ________ and ferritin ________.

Accepted Answer

The criteria for diagnosis of hemochromatosis in adult males include transferrin saturation >45% and ferritin >300 mcg/l. Therefore, option B is the correct answer. Option A has the correct transferrin saturation level, but the ferritin level is too low. Option C has a ferritin level that is too low and a transferrin saturation level that is too low. Option D has a transferrin saturation level that is too high and a ferritin level that is too low.

Question 3

Differentiate between primary and secondary hemochromatosis.

Accepted Answer

The answer of Differentiate between primary and secondary hemochromatosis....

Question 4

A defect in the HFE gene would cause which of the following to occur?

Accepted Answer

A defect in the HFE gene is associated with hereditary hemochromatosis, a condition characterized by increased iron absorption in the intestines.

Question 5

The first peripheral blood marker to show an abnormal result in iron deficiency anemia is:

Accepted Answer

CHr (corrected reticulocyte hemoglobin) or Ret-He (reticulocyte hemoglobin equivalent) are the first peripheral blood markers to show an abnormal result in iron deficiency anemia, as they indicate decreased hemoglobin content of reticulocytes due to insufficient iron supply. The other options (A, C, D) may also be abnormal in iron deficiency anemia, but not as early as CHr or Ret-He.

Question 6

The most common form of hereditary sideroblastic anemia is due to:

Accepted Answer

The most common form of hereditary sideroblastic anemia is X-linked and due to mutations in the ALAS2 gene, leading to abnormal ALAS enzyme activity and impaired heme synthesis. Plumbism (lead poisoning) can cause sideroblastic anemia but is not the most common cause. Autosomal recessive inheritance can also result in sideroblastic anemia, but it is less common than X-linked inheritance. Decreased folate levels can cause megaloblastic anemia but not sideroblastic anemia.

Question 7

How is sideroblastic anemia confirmed by laboratory analysis? Explain your answer.

Accepted Answer

The answer of How is sideroblastic anemia confirmed by laboratory...

Question 8

Alcoholics have an increased incidence of sideroblastic anemia because of which of the following?

Accepted Answer

Alcoholism can lead to an insufficient intake of vitamin B6, which is required for the proper function of enzymes involved in heme synthesis. This can result in sideroblastic anemia, in which iron-containing precursors fail to be synthesized into hemoglobin and instead accumulate in the mitochondria.

Question 9

Explain the absorption and assimilation of nonheme iron into hemoglobin in the RBC.

Accepted Answer

The answer of Explain the absorption and assimilation of nonheme...

Question 10

Hypochromic, microcytic anemia is found in which stage of iron deficiency?

Accepted Answer

Hypochromic, microcytic anemia is a common finding in stage 3 of iron deficiency, which is marked by decreased iron stores and decreased serum ferritin levels. In stage 1 and 2, iron levels may be low, but there is no anemia yet.

Question 11

The most common form of hereditary hemochromatosis is the result of which gene mutation?

Accepted Answer

The most common form of hereditary hemochromatosis is caused by a mutation in the HFE gene, which regulates iron absorption in the small intestine.

Question 12

A bone marrow aspirate is performed on a patient with sideroblastic anemia. The smear is stained with Prussian blue iron. The expected findings in this patient would be that iron stores:

Accepted Answer

Sideroblastic anemia is characterized by increased iron stores in the bone marrow, so the expected finding on a bone marrow aspirate stained with Prussian blue iron would be increased iron stores as compared with the normal control.

Question 13

The patient was found to have normal serum iron studies. What other reflex test(s) should be done?

Accepted Answer

Lead poisoning can present with normal serum iron studies, so checking blood lead levels is a relevant reflex test.

Question 14

Before treating a patient for IDA, it is important to rule out thalassemia. Explain why that is and using 3 parameters, differentiate between the two disease states.

Accepted Answer

The answer of Before treating a patient for IDA, it...

Question 15

The diagnostic test for IRIDA is:

Accepted Answer

The diagnostic test for IRIDA (Iron-refractory iron deficiency anemia) is sequencing the TMPRSS6 gene. IRIDA is caused by mutations in the TMPRSS6 gene, which codes for matriptase-2, a protein that plays a critical role in the regulation of iron absorption. Therefore, sequencing this gene can help identify any mutations or variations that may be causing the condition. Transferrin saturation and CHr are tests used to diagnose iron deficiency anemia in general, while ALAS is a test used to diagnose certain types of porphyrias.

Question 16

Explain the difference between the chemical composition of hemosiderin and that of ferritin.

Accepted Answer

The answer of Explain the difference between the chemical composition...

Question 17

Explain how lead inhibits heme synthesis.

Accepted Answer

The answer of Explain how lead inhibits heme synthesis....

Question 18

What reflex laboratory tests would be helpful to identify the cause of this anemia?

Accepted Answer

Serum iron studies can help determine if the anemia is due to iron deficiency, which is a common cause of anemia.

Question 19

Which of the following is not characteristic of iron deficiency anemia?

Accepted Answer

Decreased ZPP (zinc protoporphyrin) is actually a characteristic of iron deficiency anemia. The other options (B, C, and D) are all commonly seen in iron deficiency anemia. Decreased serum iron levels, increased TIBC (total iron binding capacity), and decreased serum ferritin levels are all used as diagnostic criteria for iron deficiency anemia.

Question 20

What is the most probable diagnosis based on these clinical findings and patient history?

Accepted Answer

Lead poisoning is the most probable diagnosis based on these clinical findings and patient history. The patient has a history of pica, which is a risk factor for lead poisoning. The patient also has abdominal pain, constipation, and vomiting, which are all symptoms of lead poisoning. The patient's blood lead level is elevated, which confirms the diagnosis of lead poisoning.

Quiz 12: Anemias of Disordered Iron Metabolism and Heme Synthesis