General Pathology Practice Questions

Q: Cystic fibrosis is due to a mutation in which chromosome?

7. **Explanation:** Cystic Fibrosis (CF) is an **autosomal recessive** multisystem disorder caused by a mutation in the **CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) gene**, which is located on the **long arm (q) of Chromosome 7** (specifically at position 7q31.2). The CFTR protein functions as a cAMP-regulated chloride channel; its defect leads to abnormally thick, viscid secretions in the lungs, pancreas, and intestines [1]. **Analysis of Options:** * **Option A (7):** Correct. The CFTR gene is located on 7q. The most common mutation is **ΔF508** (deletion of phenylalanine at position 508) [1]. * **Option B (9):** Incorrect. Chromosome 9 is associated with conditions like Friedreich’s ataxia (FXN gene) and Tuberous Sclerosis (TSC1). * **Option C (11):** Incorrect. Chromosome 11 houses genes for Beta-globin (Sickle cell anemia, Beta-thalassemia) and the WT1 gene (Wilms tumor). * **Option D (21):** Incorrect. Chromosome 21 is famously associated with Down Syndrome (Trisomy 21) and the APP gene (Alzheimer’s disease). **High-Yield Clinical Pearls for NEET-PG:** 1. **Diagnosis:** The gold standard is the **Sweat Chloride Test** (Pilocarpine iontophoresis); levels **>60 mEq/L** are diagnostic [1]. 2. **Infertility:** 95% of males with CF have **Congenital Bilateral Absence of Vas Deferens (CBAVD)** [1]. 3. **Microbiology:** *Staphylococcus aureus* is the most common lung pathogen in early childhood, while ***Pseudomonas aeruginosa*** becomes dominant in adults [1]. 4. **Newborn Screening:** Elevated **Immunoreactive Trypsinogen (IRT)** is the initial screening marker [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 475-479.

Q: Which of the following is NOT a feature of Marfan's syndrome?

Reduced joint mobility. Explanation: Marfan’s syndrome is an **autosomal dominant** connective tissue disorder caused by a mutation in the **FBN1 gene** on chromosome 15, which encodes **Fibrillin-1** [1]. Fibrillin-1 is essential for the structural integrity of the extracellular matrix and for regulating TGF-β signaling [1]. 1. **Why "Reduced joint mobility" is correct:** Patients with Marfan’s syndrome typically exhibit **joint hypermobility** (laxity) rather than reduced mobility [1]. This occurs because the defective fibrillin leads to weakened ligaments and connective tissue. In contrast, reduced joint mobility (contractures) is a hallmark of *Congenital Contractural Arachnodactyly* (Beals Syndrome), caused by FBN2 mutations. 2. **Analysis of incorrect options:** * **Arachnodactyly:** This refers to "spider-like," abnormally long and slender fingers. It is a classic skeletal feature of Marfan’s, often assessed via the Steinberg (thumb) and Walker-Murdoch (wrist) signs [1]. * **Dislocation of the lens (Ectopia lentis):** This occurs in ~60% of patients. Characteristically, the dislocation is **upward and outward** (superior-temporal) due to weakness in the ciliary zonules. * **Aortic dissection:** This is the most serious complication. Cystic medial necrosis leads to dilation of the aortic root, predisposed to Type A dissection and aortic regurgitation [1]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of death:** Aortic dissection/rupture [1]. * **Cardiovascular:** Mitral Valve Prolapse (MVP) is also frequently seen [1]. * **Differentiation:** To distinguish from Homocystinuria (which also has Marfanoid habitus), remember that Homocystinuria has **downward** lens dislocation, intellectual disability, and increased risk of thrombosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 153-154.

Q: Choristoma is defined as which of the following?

Normal tissue found at an abnormal site. **Explanation:** **Choristoma** is a developmental anomaly defined as a mass of **histologically normal tissue present in an abnormal anatomical location**. It is a type of heterotopia or ectopia. Although it presents as a mass, it is not a true neoplasm but rather a developmental "misplacement" of cells. * **Why Option C is correct:** The core concept of choristoma is "normal tissue, wrong place." A classic example is a nodule of normal pancreatic tissue found in the submucosa of the stomach or small intestine. **Analysis of Incorrect Options:** * **Option A:** Dilated vascular malformations are typically categorized under **hemangiomas** or specific vascular syndromes (like Sturge-Weber), not choristomas. * **Option B:** Malignant stroma of stem cells describes a **malignant mixed tumor** or certain types of **sarcomas/blastomas**. Choristomas are inherently benign and composed of mature, well-differentiated cells. * **Option C:** This describes a **Hamartoma**. While often confused with choristoma, a hamartoma is an excessive, disorganized growth of mature cells indigenous to that particular site (e.g., a lung hamartoma containing cartilage and bronchial epithelium). **High-Yield Clinical Pearls for NEET-PG:** * **Choristoma vs. Hamartoma:** Remember the mnemonic: **C**horistoma = **C**hange of location; **H**amartoma = **H**abitat is normal (but disorganized). * **Common Examples of Choristoma:** Pancreatic tissue in the Meckel’s diverticulum or stomach; Gastric mucosa in the esophagus (Inlet patch). * **Common Examples of Hamartoma:** Luschka’s ducts in the gallbladder; Peutz-Jeghers polyps; Hypothalamic hamartomas. * Both are considered **pseudotumors** because they form a mass but lack the autonomous growth characteristic of true neoplasia.

Question 1

Which of the following is an X-linked recessive disorder?

Accepted Answer

Hemophilia A

Answer

Sickle cell anemia

Answer

Thalassemias

Answer

von Willebrand disease

Question 2

The tumor suppressor gene p53 induces cell arrest at which phase?

Accepted Answer

G1-S phase

Answer

G2-M phase

Answer

S-G2 phase

Answer

G0 phase

Question 3

A 10-year-old male, who is mentally retarded, can perform daily living activities, including feeding and dressing himself. Physical examination reveals brachycephaly, oblique palpebral fissures with prominent epicanthal folds, and a single transverse palmar crease. Auscultation of the chest reveals a grade III/IV systolic murmur. Which of the following conditions is most likely to be present by the age of 20?

Accepted Answer

Acute leukemia

Answer

Hepatic cirrhosis

Answer

Chronic renal failure

Answer

Acute myocardial infarction

Question 4

A 40-year-old man presents with a chronic cough and fever for several months. Chest radiography reveals a diffuse reticulonodular pattern. Microscopic examination of a transbronchial biopsy shows focal areas of inflammation containing epithelioid cell granulomas, Langhans giant cells, and lymphocytes. These findings are typical for which of the following types of hypersensitivity immunologic responses?

Accepted Answer

Type IV

Answer

Type I

Answer

Type II

Answer

Type III

Question 5

Cystic fibrosis is due to a mutation in which chromosome?

Accepted Answer

7

Answer

9

Answer

11

Answer

21

Question 6

Which of the following is NOT a feature of Marfan's syndrome?

Accepted Answer

Reduced joint mobility

Answer

Arachnodactyly

Answer

Dislocation of the lens

Answer

Aortic dissection

Question 7

Which of the following causes apoptotic damage to sperms?

Accepted Answer

Chlamydia

Answer

Treponema pallidum

Answer

Clostridium

Answer

Hemophilus ducreyi

Question 8

Choristoma is defined as which of the following?

Accepted Answer

Normal tissue found at an abnormal site

Answer

Dilated vascular malformation

Answer

Malignant stroma of stem cells

Answer

Benign tumor in which normal elements become abnormally overgrown

Question 9

The intrinsic apoptotic pathway is located in which of the following cellular organelles?

Accepted Answer

Mitochondria

Answer

Endoplasmic reticulum

Answer

Golgi apparatus

Answer

Cell membrane

Question 10

The chromosome on which the Rhesus (Rh) blood group gene is located is?

Accepted Answer

Chromosome 1

Answer

Chromosome 3

Answer

Chromosome 6

Answer

Chromosome 9

General Pathology — MCQs

General Pathology — MCQs

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