General Pathology Practice Questions

Q: Mutation in Marfan's syndrome is associated with which gene?

Fibrillin I. **Explanation:** **Marfan’s Syndrome** is an autosomal dominant disorder of connective tissue caused by a mutation in the **FBN1 gene** located on chromosome **15q21**. This gene encodes **Fibrillin-1**, a glycoprotein that serves as a major structural component of extracellular microfibrils. These microfibrils form a scaffold for the deposition of elastin and are essential for maintaining the structural integrity of tissues such as the aortic wall, skeletal system, and the suspensory ligaments of the lens. **Analysis of Options:** * **Fibrillin-1 (Correct):** Mutations lead to mechanical weakness of connective tissues and excessive activation of **TGF-β**, which contributes to the clinical manifestations (e.g., aortic root dilation) [1]. * **Collagen I:** Mutations here are associated with **Osteogenesis Imperfecta** (brittle bone disease) and certain types of Ehlers-Danlos Syndrome. * **Collagen IV:** This is a key component of the basement membrane; mutations are associated with **Alport Syndrome**. * **Fibrillin-2:** Mutations in the FBN2 gene (chromosome 5) cause **Congenital Contractural Arachnodactyly** (Beals Syndrome), which mimics Marfan’s but lacks the cardiac and ocular complications. **Clinical Pearls for NEET-PG:** 1. **Skeletal:** Dolichostenomelia (long limbs), arachnodactyly (long fingers), and pectus excavatum [1]. 2. **Ocular:** **Ectopia lentis** (dislocation of the lens), typically **upward and outward** (superior-temporal). 3. **Cardiovascular:** The most life-threatening complication is **Aortic Dissection** preceded by cystic medial necrosis. Mitral Valve Prolapse (MVP) is also common [1]. 4. **Diagnostic Sign:** Steinberg sign (thumb sign) and Walker-Murdoch sign (wrist sign). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 153-154.

Question 1

Mutation in Marfan's syndrome is associated with which gene?

Accepted Answer

Fibrillin I

Answer

Collagen I

Answer

Collagen IV

Answer

Fibrillin II

Question 2

Which component does C3 convertase act on?

Accepted Answer

C3

Answer

C4b2b

Answer

C4b2B3a

Answer

C4b

Question 3

The complex process of leukocyte movements through the blood vessels includes all EXCEPT:

Accepted Answer

Phagocytosis

Answer

Rolling

Answer

Adhesion

Answer

Migration

Question 4

Anti U1-14NP antibody is seen in which condition?

Accepted Answer

Mixed Connective Tissue Disease (MCTD)

Answer

Systemic Lupus Erythematosus (SLE)

Answer

Scleroderma

Answer

Dermatomyositis

Question 5

Amyloid deposits stain positively with all of the following stains except?

Accepted Answer

Methenamine silver

Answer

Congo Red

Answer

Crystal violet

Answer

Thioflavin

Question 6

Some cells release messengers locally and possess cell surface receptors for the same messengers, enabling those cells to respond to their own secreted products. This has been implicated in the growth of certain cancers. Which of the following is an important example of this phenomenon?

Accepted Answer

Colorectal cancer

Answer

Pancreatic malignancy

Answer

Lymphoma

Answer

Gastric maltoma

Question 7

Senescent cells are deficient in which enzyme?

Accepted Answer

Telomerase

Answer

RNA polymerase

Answer

DNA polymerase

Answer

Helicase

Question 8

What is the chemical nature of the amyloid deposited in immunocyte dyscrasias with amyloidosis?

Accepted Answer

Immunoglobulin light chain (AL amyloid)

Answer

Serum amyloid A (SAA)

Answer

Prealbumin

Answer

Beta 2 microglobulin

Question 9

Klinefelter syndrome is diagnosed by:

Accepted Answer

Karyotyping

Answer

USG abdomen

Answer

Echocardiography

Answer

Triple test

Question 10

Which of the following features is not characteristic of Fragile X syndrome?

Accepted Answer

Micro-orchidism

Answer

Hyperextensible joints

Answer

Small nose

Answer

Mental retardation

General Pathology — MCQs

General Pathology — MCQs

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