Microcytic Anemia MCQs

Ceruloplasmin acts as an oxidase for a variety of substrates, one of which is ferrous iron. There is evidence that ceruloplasmin is required for the optimal mobilization of iron from cells to plasma. Reference: Wintrobes 14th/p 813

Thalasemias are inherited disorders caused by mutations in globin genes that decrease the synthesis of α- or β-globin. Decreased synthesis of one globin results not only in a deficiency of Hb, but also in red cell damage that is caused by precipitates formed from excess unpaired "normal" globin chains. The mutations that cause thalassemia are particularly common in Mediterranean, African, and Asian regions in which malaria is endemic. As with HbS, it is hypothesized that globin mutations associated with thalassemia protect against falciparum malaria. Reference: Robbins, 10 th edition page number - 447

Screening tests for Thalassemia trait: NESTROFT (Naked Eye Single Tube Red cell Osmotic Fragility Test) assesses osmotic fragility of red cells at a single concentration of buffered saline (0.36% in single tube) Reference: Robbins 9th/pg 638; 8th/pg 648

A two-year-old child is suffering from beta-thalessemia. Replacement of amino acid by a stop codon illustrates nonsense mutation. The presence of this premature stop codon results in the production of shortened and likely non-functional protein. The example of disease in which nonsense mutations are known to be among the causes that includes: Cystic fibrosis, Beta thalassemia, hurler syndrome. Reference: Robbins basic pathology, 10 th ed, Pg: 244

Hemoglobin adducts are post- translational modifications of hemoglobin molecules. When glucose is added to hemoglobin A, it is known as HbA1c. Similarly individuals with HbS and HbC will have HbS1c and HbC1c, respectively. When the hemoglobin molecule is aged, glutathione becomes bound to cysteine at the 93rd position of the β chain. When this occurs to HbA, this is known as HbA1d or HbAIII. Similarly, patients can have HbS1d and HbC1d, if they have HbS and HbC respectively. Hemoglobin Constant Spring is not a hemoglobin adduct. It is an abnormal hemoglobin that may be seen in individuals with α thalassemia. Reference: Robbins & Cotran Pathologic Basis of Diseases 10 th edition, chapter 3, pg 72

In iron deficiency anemia, TIBC (Total iron-binding capacity) is increased, transferrin saturation is decreased, and ferritin is decreased. The diagnosis of IDA ultimately rests on laboratory studies Serum Fe and ferritin are low and the total plasma Fe binding capacity is high. Low serum Fe with increased Fe binding capacity results in a reduction of transferring saturation to below 15%. Reference: Robbins 9th/pg 659

Causes of acquired sideroblastic anemia are Excessive alcohol use Vitamin B6 or copper deficiency Lead poisoning or zinc overdose Cancer or myelodysplastic syndrome Certain medications, such as antibiotics, chemotherapeutics, and chelators Reference: Robbins, 10 th edition, page number - 364

Transferrin is quantified in terms of the amount of iron it will bind, a measure called the total iron-binding capacity (TIBC; In the average subject, the plasma iron concentration is ∼(100 μg/dL), and the TIBC is ∼(300 μg/dL). Serum iron concentration is reduced in iron deficiency, and the TIBC is often increased. Reference: Robbins & cotran pathologic basis of diseases, 10 th edition Chapter 14, pg 655