Hematopathology — MCQs

Hematopathology Indian Medical PG Practice Questions and MCQs

Question 821: Coagulation defects associated with increased coagulation are seen in which of the following conditions?

A. Increased Protein C
B. Increased Protein B
C. Increased Anti-thrombin HE
D. Protein C resistance (Correct Answer)

Explanation: **Explanation:** The correct answer is **Protein C resistance**. This condition is a classic example of a **thrombophilic state** (hypercoagulability), where the blood has an increased tendency to clot [1]. **1. Why Protein C Resistance is Correct:** Protein C is a natural anticoagulant that, when activated (APC), degrades Factors Va and VIIIa to inhibit clot formation. In **Protein C resistance**—most commonly caused by the **Factor V Leiden mutation**—Factor V is structurally altered [1]. This mutation prevents Activated Protein C from binding to and cleaving Factor V. Consequently, Factor V remains active in the coagulation cascade for longer, leading to excessive thrombin generation and an increased risk of venous thromboembolism (VTE) [1]. **2. Why the Other Options are Incorrect:** * **Increased Protein C & Increased Anti-thrombin III:** Both Protein C and Anti-thrombin III are **natural anticoagulants** [1]. An *increase* in these levels would actually decrease the risk of coagulation (bleeding tendency), whereas a *deficiency* leads to thrombosis. * **Increased Protein B:** This is a distractor; Protein B does not play a recognized role in the clinical coagulation cascade relevant to thrombophilia. **3. NEET-PG High-Yield Pearls:** * **Factor V Leiden:** The most common inherited cause of hypercoagulability (thrombophilia) in Caucasians [1]. It involves a point mutation (G1691A) in the Factor V gene [1]. * **Virchow’s Triad:** Remember the three factors contributing to thrombosis: Endothelial injury, Stasis, and Hypercoagulability. * **Warfarin-Induced Skin Necrosis:** This occurs in patients with **Protein C deficiency** when starting Warfarin, due to the rapid depletion of Protein C (short half-life) before the depletion of procoagulant factors. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-134.

Question 822: Which of the following is NOT true about histiocytosis X?

A. Seborrheic dermatitis is a known feature
B. Birbeck's granules are a characteristic feature
C. Lytic bony lesions are known
D. Associated with angiomyolipoma of the kidney (Correct Answer)

Explanation: **Explanation:** **Histiocytosis X**, now more commonly known as **Langerhans Cell Histiocytosis (LCH)**, is a clonal proliferation of Langerhans cells [1]. **Why Option D is the correct answer:** Langerhans Cell Histiocytosis is **not** associated with renal angiomyolipoma. Angiomyolipoma of the kidney is a classic feature of **Tuberous Sclerosis**, a neurocutaneous syndrome [2]. LCH, while multisystemic, primarily involves the bone, skin, and lungs, but does not typically manifest with renal hamartomas [2]. **Analysis of Incorrect Options:** * **Option A:** Seborrheic-like dermatitis (scaly, erythematous rash) is a classic cutaneous presentation of LCH, particularly in the Letterer-Siwe disease variant seen in infants. * **Option B:** **Birbeck granules** are the pathognomonic ultrastructural hallmark of LCH [1]. Seen on electron microscopy, they are "tennis-racket" shaped pentalaminar structures containing the protein **Langerin (CD207)** [1]. * **Option C:** Lytic "punched-out" bony lesions (especially in the skull) are the most common clinical presentation, particularly in the Eosinophilic Granuloma variant. **High-Yield Clinical Pearls for NEET-PG:** * **Immunophenotype:** LCH cells are positive for **S100, CD1a, and Langerin (CD207)** [1]. * **Hand-Schüller-Christian Disease:** A clinical triad of LCH consisting of: 1. Lytic skull lesions, 2. Exophthalmos, and 3. Diabetes Insipidus. * **Morphology:** Cells have characteristic "coffee-bean" nuclei (grooved nuclei) [1]. * **Prognosis:** Letterer-Siwe (Multisystem) has the worst prognosis; Eosinophilic Granuloma (Unifocal) has the best. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 629-630. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Central Nervous System, pp. 1318-1319.

Question 823: Differential white blood cell counts in the laboratory are useful in the diagnosis of which of the following conditions?

A. Anemia
B. Eosinophilia (Correct Answer)
C. Spherocytosis
D. Thrombocytopenic purpura

Explanation: **Explanation:** The **Differential White Blood Cell (WBC) count** is a laboratory test that measures the percentage and absolute number of each type of leukocyte (neutrophils, lymphocytes, monocytes, eosinophils, and basophils) in the blood. It is specifically designed to identify abnormalities in the white cell lineage. * **Why Option B is Correct:** **Eosinophilia** is defined as an absolute eosinophil count (AEC) greater than 500/µL [1]. Since the differential count directly quantifies eosinophils, it is the primary diagnostic tool for identifying this condition, which is commonly associated with Type I hypersensitivity reactions (asthma, hay fever), parasitic infections, and certain malignancies (Hodgkin lymphoma) [1], [2]. * **Why Other Options are Incorrect:** * **Anemia (A):** This is a condition characterized by low hemoglobin or red blood cell (RBC) count. It is diagnosed via Hemoglobin levels and RBC indices (MCV, MCH), not WBC differentials. * **Spherocytosis (C):** This is a morphological abnormality of RBCs (loss of central pallor). While it is seen on a peripheral blood smear, it is a red cell disorder diagnosed via the Osmotic Fragility Test or EMA binding test. * **Thrombocytopenic Purpura (D):** This involves a decrease in **platelets** (thrombocytes), leading to bleeding manifestations. It is diagnosed via a platelet count, not a differential WBC count. **NEET-PG High-Yield Pearls:** * **Normal Eosinophil Range:** 1–6% of total WBCs. * **Causes of Eosinophilia (Mnemonic: NAACP):** **N**eoplasia, **A**llergy/Asthma, **A**ddison’s disease, **C**onnective tissue disorders, **P**arasites [1]. * **Shift to the Left:** An increase in immature neutrophils (band cells) in the differential count, usually indicating acute bacterial infection [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, p. 592. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 580-581.

Question 824: Which of the following haemoglobin estimations will be diagnostically helpful in a case of beta thalassemia trait?

A. Hb-F
B. Hb-C
C. Hb-A2 (Correct Answer)
D. Hb-H

Explanation: Explanation: In Beta-thalassemia trait (minor), there is a partial reduction in the synthesis of $eta$-globin chains [2]. To compensate for this deficiency, the body increases the production of $\delta$-globin chains, which combine with $\alpha$-chains to form Hemoglobin A2 ($\alpha_2\delta_2$). * Why Hb-A2 is correct: An elevated Hb-A2 level (>3.5%) is the diagnostic hallmark and the most reliable screening tool for Beta-thalassemia trait. It is typically measured using High-Performance Liquid Chromatography (HPLC) or electrophoresis. Analysis of Incorrect Options: * Hb-F ($\alpha_2\gamma_2$): While Hb-F can be mildly elevated (1–5%) in Beta-thalassemia trait, it is inconsistent and not diagnostic [3]. Significant elevations of Hb-F are more characteristic of Beta-thalassemia Major [3]. * Hb-C: This is a structural hemoglobin variant caused by a specific mutation in the $\beta$-globin gene (glutamic acid replaced by lysine). It is unrelated to the quantitative chain deficiency seen in thalassemia. * Hb-H ($\beta_4$): This occurs when there is a severe deficiency of $\alpha$-chains, leading to $\beta$-chain tetramers. It is the hallmark of Alpha-thalassemia (3-gene deletion), not Beta-thalassemia. High-Yield Clinical Pearls for NEET-PG: * Mentzer Index: (MCV/RBC count) $<13$ suggests Thalassemia trait, while $>13$ suggests Iron Deficiency Anemia (IDA). * Peripheral Smear: Characterized by microcytic hypochromic anemia with target cells and basophilic stippling [1]. * RBC Count: In Beta-thalassemia trait, the RBC count is often paradoxically elevated despite low hemoglobin, unlike IDA where the count is usually low. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 590-591. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 646-647. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 648.

Question 825: Pancytopenia with cellular bone marrow is seen in all EXCEPT?

A. Megaloblastic Anemia
B. Myelodysplastic Syndrome (MDS)
C. Paroxysmal Nocturnal Hemoglobinuria (PNH)
D. Glucose-6-Phosphate Dehydrogenase (G6PD) deficiency (Correct Answer)

Explanation: **Explanation:** The core concept of this question lies in distinguishing between **ineffective hematopoiesis** (where the marrow is busy but cells die before reaching circulation) and **isolated hemolysis**. **Why G6PD Deficiency is the correct answer:** G6PD deficiency typically presents as an **isolated hemolytic anemia**, not pancytopenia [1]. During oxidative stress (e.g., fava beans, infections, or drugs), only red blood cells undergo hemolysis [1]. The white blood cell and platelet counts remain normal. Therefore, it does not cause pancytopenia. **Analysis of Incorrect Options (Causes of Pancytopenia with Cellular Marrow):** * **Megaloblastic Anemia:** Vitamin B12 or Folate deficiency leads to impaired DNA synthesis. This results in **ineffective hematopoiesis**, where the marrow is hypercellular with megaloblasts, but the cells are destroyed within the marrow, leading to pancytopenia in the peripheral blood. * **Myelodysplastic Syndrome (MDS):** Characterized by clonal stem cell defects and "dysplastic" changes. The marrow is usually hypercellular, but the cells are morphologically abnormal and undergo premature apoptosis, resulting in peripheral cytopenias. * **Paroxysmal Nocturnal Hemoglobinuria (PNH):** PNH is a unique stem cell disorder [1]. While it often presents with hemolytic anemia, it is frequently associated with bone marrow failure syndromes. It can present with a cellular marrow (during hemolytic phases) or progress from/to aplastic anemia, often showing pancytopenia. **NEET-PG High-Yield Pearls:** * **Pancytopenia with Hypocellular Marrow:** Aplastic Anemia, Hypoplastic MDS, Fanconi Anemia. * **Pancytopenia with Hypercellular Marrow:** Megaloblastic anemia, MDS, Aleukemic leukemia, Subleukemic leukemia, and Myelofibrosis (early stage). * **G6PD Hallmark:** Look for **"Heinz bodies"** (denatured hemoglobin) and **"Bite cells"** (degluticytes) on a peripheral smear. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 638, 652-654.

Question 826: The pathogenesis of hypochromic anemia in lead poisoning is due to which of the following mechanisms?

A. Lead blocks transferrin receptors of erythroid precursors
B. Lead binds to transferrin, inhibiting the transport of iron
C. Inhibition of enzymes involved in heme biosynthesis (Correct Answer)
D. Inhibition of the breakdown of ferritin into hemosiderin

Explanation: ### Explanation **Correct Answer: C. Inhibition of enzymes involved in heme biosynthesis** Lead poisoning (Plumbism) causes a microcytic hypochromic anemia primarily by interfering with the heme biosynthetic pathway [1]. Lead inhibits two critical enzymes: 1. **$̔$-aminolevulinic acid dehydratase (ALAD):** This prevents the conversion of ALA to porphobilinogen, leading to an accumulation of ALA in the blood and urine. 2. **Ferrochelatase:** This enzyme is responsible for the final step of heme synthesis—inserting ferrous iron into protoporphyrin IX. When inhibited, iron cannot be incorporated, leading to an accumulation of **zinc protoporphyrin**. The resulting deficiency in heme synthesis leads to reduced hemoglobin production, manifesting as hypochromic anemia [1]. **Analysis of Incorrect Options:** * **Options A & B:** Lead does not significantly interfere with transferrin or its receptors. Iron transport remains functional; the defect lies in the *utilization* of iron within the mitochondria of the erythroblast. * **Option D:** Lead does not inhibit the breakdown of ferritin. In fact, because iron cannot be used for heme, it accumulates in the mitochondria, often forming "ring sideroblasts" (though more common in sideroblastic anemia, they can be seen in lead toxicity). **High-Yield Clinical Pearls for NEET-PG:** * **Basophilic Stippling:** A classic peripheral smear finding in lead poisoning caused by the inhibition of **Pyrimidine 5'-nucleotidase**, leading to the persistence of ribosomal RNA fragments [1]. * **Burton’s Line:** A bluish-purple line on the gingival margins due to lead sulfide precipitation. * **Radiology:** "Lead lines" (increased density) at the metaphyses of growing long bones in children [1]. * **Treatment:** Chelation therapy with **Succimer** (oral, first-line in kids) or **CaNa₂EDTA** and **Dimercaprol (BAL)**. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 419-420.

Question 827: Which of the following agents is a prerequisite for Prothrombin time (PT) assay?

A. Tissue thromboplastin (Correct Answer)
B. Kaolin
C. Glass beads
D. Silica

Explanation: **Explanation:** The **Prothrombin Time (PT)** assay is used to evaluate the **Extrinsic** and **Common pathways** of the coagulation cascade. It specifically measures the activity of Factors VII, X, V, II (Prothrombin), and I (Fibrinogen). **Why Tissue Thromboplastin is correct:** To initiate the extrinsic pathway in a laboratory setting, the patient’s citrated plasma must be exposed to **Tissue Factor (Factor III)**. **Tissue Thromboplastin** (a combination of tissue factor and phospholipids) along with **Calcium** is added to the plasma [2]. This activates Factor VII, triggering the cascade that leads to fibrin clot formation [1]. The time taken for this clot to form is the PT. **Analysis of Incorrect Options:** * **Kaolin, Silica, and Glass beads:** These are all **surface activators** used in the **Activated Partial Thromboplastin Time (aPTT)** assay. They provide a negatively charged surface to activate Factor XII (Hageman factor), which initiates the **Intrinsic pathway** [2]. They are not used in PT. **High-Yield Clinical Pearls for NEET-PG:** * **PT/INR** is the investigation of choice for monitoring **Warfarin (Oral Anticoagulant)** therapy and assessing **Liver Function** (as the liver synthesizes these factors) [3]. * **aPTT** is used to monitor **Unfractionated Heparin** therapy. * **Vitamin K deficiency** affects Factors II, VII, IX, and X; however, because Factor VII has the shortest half-life, the **PT is the first to be prolonged** [3]. * **Normal PT range:** Approximately 11–13 seconds. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 126-128. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 128-130. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 582-583.

Question 828: Atypical lymphocytes in infectious mononucleosis are primarily composed of which cell type?

A. CD4+ T cells
B. CD8+ T cells (Correct Answer)
C. Plasma cells
D. NK cells

Explanation: Infectious Mononucleosis (IM), typically caused by the **Epstein-Barr Virus (EBV)**, is characterized by the presence of **atypical lymphocytes** (also known as **Downey cells**) in the peripheral blood smear. **Why CD8+ T cells are correct:** EBV primarily infects B cells by binding to the **CD21 receptor** (CR2). In response to this B-cell infection, the body mounts a robust cell-mediated immune response. The "atypical lymphocytes" seen on a blood film are not the infected B cells themselves, but rather **reactive, activated CD8+ Cytotoxic T cells** that are proliferating to eliminate the EBV-infected B cells [1]. These cells are characteristically large with abundant pale blue cytoplasm that "hugs" or indents around adjacent red blood cells [1]. **Why other options are incorrect:** * **CD4+ T cells:** While involved in the overall immune coordination, they do not form the bulk of the atypical lymphocytic population in IM. * **Plasma cells:** These are terminal B-cell derivatives. While polyclonal B-cell activation occurs in IM (leading to heterophile antibodies), they do not constitute the "atypical lymphocytes." * **NK cells:** Although they participate in the innate response against viral infections, they are not the primary cell type identified as Downey cells. **High-Yield NEET-PG Pearls:** * **Triad of IM:** Fever, Pharyngitis, and Lymphadenopathy (posterior cervical) [1]. * **Diagnosis:** **Monospot test** (detects heterophile antibodies) is the screening test of choice. * **Paul-Bunnell Test:** Specific heterophile antibody test using sheep RBCs. * **Complication:** Avoid Ampicillin/Amoxicillin as it can cause a characteristic **maculopapular rash**. * **Splenic Rupture:** Patients should avoid contact sports for 3–4 weeks due to the risk of rupture from splenomegaly. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 369-370.

Question 829: Which of the following is NOT a congenital cause of hypercoagulable states?

A. Protein C deficiency
B. Protein S deficiency
C. MTHFR mutation
D. Antithrombin III deficiency (Correct Answer)

Explanation: **Explanation:** The question asks for the option that is **NOT** a congenital cause of hypercoagulable states. However, there appears to be a technical error in the provided key: **Antithrombin III deficiency is, in fact, a well-known congenital (hereditary) cause** of thrombophilia. In standard medical literature, all four options listed (Protein C, Protein S, ATIII deficiency, and MTHFR mutations) are considered hereditary/congenital factors [1]. If this were a "select the best" question where one must be excluded, **MTHFR mutation (Option C)** is often the intended answer in modern clinical practice. While it is a genetic mutation, its clinical significance in causing thrombosis is now considered controversial and weak compared to the "strong" thrombophilias (Protein C, S, and ATIII). **Breakdown of Options:** * **Antithrombin III Deficiency (Option D):** A potent hereditary thrombophilia. It is inherited in an autosomal dominant fashion. Patients often show **heparin resistance** because heparin requires ATIII to exert its anticoagulant effect. * **Protein C & S Deficiency (Options A & B):** These are vitamin K-dependent natural anticoagants. Congenital deficiencies lead to an inability to inactivate Factors Va and VIIIa. A high-yield complication is **Warfarin-induced skin necrosis** [1]. * **MTHFR Mutation (Option C):** Leads to hyperhomocysteinemia. While genetic, many guidelines no longer include it in routine workups for inherited thrombophilia because its association with venous thromboembolism (VTE) is inconsistent. **NEET-PG High-Yield Pearls:** 1. **Most common inherited cause of hypercoagulability:** Factor V Leiden (resistance to activated Protein C) [1]. 2. **Most "potent" inherited cause:** Antithrombin III deficiency (highest risk of VTE). 3. **Neonatal Purpura Fulminans:** Seen in homozygous Protein C deficiency. 4. **Acquired causes to remember:** Antiphospholipid Syndrome (APLS), Nephrotic syndrome, and Oral Contraceptive Pills (OCPs). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Hemodynamic Disorders, Thromboembolic Disease, and Shock, pp. 133-134.

Question 830: A 65-year-old man presents with anemia, splenomegaly, and extramedullary hematopoiesis. He reports easy fatigability, weight loss, and weakness. A bone marrow biopsy reveals marked proliferation of fibrous tissue (myelofibrosis). Which of the following is a characteristic finding in this disorder?

A. Depletion of bone marrow megakaryocytes
B. Teardrop-shaped erythrocytes (Correct Answer)
C. Autosplenectomy
D. Neoplastic plasma cells in the bone marrow

Explanation: ### Explanation The clinical presentation of anemia, massive splenomegaly, and bone marrow fibrosis in an elderly patient is classic for **Primary Myelofibrosis (PMF)**, a chronic myeloproliferative neoplasm. **1. Why the Correct Answer is Right:** In PMF, the bone marrow is replaced by dense collagen (fibrosis) due to the release of fibrogenic factors (like TGF-β) from neoplastic megakaryocytes [2]. As red blood cells (RBCs) attempt to exit the fibrotic marrow or are produced in the spleen (extramedullary hematopoiesis), they are physically squeezed and damaged [1]. This mechanical trauma results in the formation of **Teardrop-shaped erythrocytes (Dacrocytes)**, a hallmark finding on the peripheral blood smear [1]. **2. Why the Incorrect Options are Wrong:** * **Option A:** PMF is actually characterized by an **increase and clustering of atypical, pleomorphic megakaryocytes**. These cells are responsible for driving the fibrosis [2]. * **Option C:** **Autosplenectomy** is characteristic of Sickle Cell Anemia due to repeated infarctions [3]. In PMF, the spleen undergoes **massive enlargement** (splenomegaly) because it takes over the role of blood cell production (extramedullary hematopoiesis) [1], [2]. * **Option D:** Neoplastic plasma cells are the hallmark of **Multiple Myeloma**, not myelofibrosis. **3. Clinical Pearls for NEET-PG:** * **Leukoerythroblastic Picture:** The peripheral smear often shows immature WBCs and nucleated RBCs due to the loss of the marrow-blood barrier [1]. * **Dry Tap:** Bone marrow aspiration often results in a "dry tap" due to extensive fibrosis; diagnosis requires a **trephine biopsy**. * **Genetic Mutations:** Look for **JAK2 V617F** (approx. 50-60% of cases), **CALR**, or **MPL** mutations [2]. * **Staining:** Silver stains (Reticulin stain) are used to demonstrate increased reticulin fibers in the marrow. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 628-629. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 644-645.

Practice by Chapter

Anemias: Classification and Approach

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Hemolytic Anemias

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Myeloproliferative Neoplasms

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Myelodysplastic Syndromes

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Acute Leukemias

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Chronic Leukemias

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Lymphomas and Lymphoid Neoplasms

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Plasma Cell Disorders

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Bleeding Disorders

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Thrombotic Disorders

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