One of the following disorders in which an abnormal haemoglobin leads to chronic hemolytic anemia with other clinical manifestations due to point mutation of DNA is?

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

Sickle cell anemia is a classic example of a disease caused by a point mutation in the DNA.
This specific mutation occurs in the β-globin gene, causing the amino acid glutamic acid to be replaced by valine.
This substitution results in the formation of an abnormal hemoglobin called Hemoglobin S (HbS).
When deoxygenated, HbS molecules polymerize and cause red blood cells to deform into a sickle shape.
These sickled cells are fragile, leading to chronic hemolytic anemia, and can block blood vessels, causing tissue ischemia.

Option A: Thalassemia is a quantitative hemoglobin disorder characterized by the reduced synthesis of normal globin chains, not the production of a structurally abnormal hemoglobin due to a specific point mutation as described.
Option B: Haemophilia is a bleeding disorder resulting from a deficiency of clotting factors. It is unrelated to hemoglobin structure or red blood cell function.
Option C: Haemoglobinopathy is a general term for all genetic disorders of hemoglobin. The question provides a very specific set of characteristics (point mutation, abnormal Hb, hemolytic anemia) that precisely define sickle cell anemia, making the specific term a better choice than the general category.

Clinical Relevance

Nursing practice connection: Knowing Pathophysiology of Hemoglobinopathies helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
A key nursing priority in managing a sickle cell vaso-occlusive crisis is summarized by the mnemonic HOP: Hydration, Oxygenation, and Pain management.
Hydration (with IV fluids) helps reduce blood viscosity and prevent further sickling. Oxygenation can help reverse sickling in hypoxic areas. Pain management is crucial as vaso-occlusive crises are extremely painful.
What if? If the patient had sickle cell trait (heterozygous, HbAS) instead of sickle cell disease (homozygous, HbSS), they would be largely asymptomatic. Crises would only be triggered by extreme conditions like severe dehydration, high altitudes, or extreme exertion, and nursing management would focus on prevention and education about these triggers.

How to Approach the Question

First, break down the question into its core components: 1) abnormal hemoglobin, 2) chronic hemolytic anemia, and 3) caused by a point mutation.
Evaluate each option against these three specific criteria.
Immediately eliminate Haemophilia, as it's a clotting disorder, not a hemoglobin disorder.
Compare Thalassemia and Sickle cell anemia. Recognize that Thalassemia is a quantitative problem (less hemoglobin made), while the question describes a qualitative problem (abnormal hemoglobin made) due to a point mutation.
Consider the term Haemoglobinopathy. While technically correct as a category, it's too general. The question's detailed description points to a specific disease, making 'Sickle cell anemia' the most precise and therefore the best answer.
Select the option that fits all parts of the detailed description provided in the stem.

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart B (pp 233-449 of 464) p. 141-143

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 643-645

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