General Pathology — MCQs

General Pathology Indian Medical PG Practice Questions and MCQs

Question 401: Mutation in Marfan's syndrome is associated with which gene?

A. Collagen I
B. Collagen IV
C. Fibrillin I (Correct Answer)
D. Fibrillin II

Explanation: **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 402: Which component does C3 convertase act on?

A. C4b2b
B. C4b2B3a
C. C4b
D. C3 (Correct Answer)

Explanation: **Explanation:** The complement system is a crucial part of innate immunity, involving a cascade of proteins that lead to pathogen opsonization and lysis. The central event in all three pathways (Classical, Lectin, and Alternative) is the formation of **C3 convertase** [1], [2]. **Why C3 is the correct answer:** C3 convertase is an enzyme complex whose specific substrate is **C3** [1]. It cleaves the C3 molecule into two fragments: **C3a** (an anaphylatoxin) and **C3b** (an opsonin) [1], [2]. The deposition of C3b on the microbial surface is the most critical step in complement activation, as it leads to the formation of C5 convertase and the subsequent Membrane Attack Complex (MAC) [1]. **Analysis of Incorrect Options:** * **A. C4b2b:** This is not the substrate, but rather the **Classical/Lectin pathway C3 convertase** itself. It acts *on* C3. * **B. C4b2B3a:** This is an incorrect nomenclature. The C5 convertase of the classical pathway is **C4b2b3b**, which is formed when C3b binds to the C3 convertase. * **C. C4b:** This is a fragment of C4 that serves as a structural component of the C3 convertase in the classical pathway; it is not the substrate for the enzyme. **NEET-PG High-Yield Pearls:** * **Classical/Lectin C3 Convertase:** C4b2b (older texts may use C4b2a). * **Alternative C3 Convertase:** C3bBb [3]. * **C3b Function:** Acts as a powerful **opsonin**, facilitating phagocytosis via CR1 receptors on macrophages [2]. * **C3 Deficiency:** The most severe complement deficiency, leading to increased susceptibility to pyogenic infections (e.g., *S. pneumoniae*) and Type III hypersensitivity reactions. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 99-100. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 162-163. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 534-535.

Question 403: The complex process of leukocyte movements through the blood vessels includes all EXCEPT:

A. Rolling
B. Adhesion
C. Migration
D. Phagocytosis (Correct Answer)

Explanation: ### Explanation The question asks to identify the step that is **not** part of the movement of leukocytes through blood vessels (extravasation). **1. Why Phagocytosis is the Correct Answer:** Phagocytosis is the process by which a cell (like a macrophage or neutrophil) engulfs and destroys particles, pathogens, or debris [4]. It is a **functional outcome** of leukocyte activation that occurs **after** the leukocyte has already exited the blood vessel and reached the site of injury in the interstitial tissue. It is not a mechanism of movement through the vessel wall itself. **2. Analysis of Incorrect Options (Steps of Leukocyte Extravasation):** * **Rolling (A):** This is the initial step where leukocytes tumble along the endothelial surface [3]. It is mediated by **Selectins** (L-selectin on leukocytes; E and P-selectins on endothelium) [3]. * **Adhesion (B):** This is the firm attachment of leukocytes to the endothelium [3]. It is mediated by **Integrins** (on leukocytes) binding to ligands like ICAM-1 and VCAM-1 (on endothelium) [1]. * **Migration (C):** Also known as **Diapedesis** or Transmigration [2]. This is the process where leukocytes squeeze through endothelial junctions to enter the extravascular space, primarily mediated by **PECAM-1 (CD31)** [1]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Sequence of Extravasation:** Margination → Rolling → Adhesion → Transmigration (Diapedesis) → Chemotaxis [1]. * **Leukocyte Adhesion Deficiency (LAD) Type 1:** Caused by a defect in **CD18** (integrin subunit), leading to impaired firm adhesion and recurrent infections without pus formation [1]. * **LAD Type 2:** Caused by a defect in **Sialyl-Lewis X** (selectin ligand), leading to impaired rolling. * **Chemotaxis:** The most common exogenous chemoattractants are bacterial products; endogenous ones include **C5a, LTB4, and IL-8** [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, pp. 87-89. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 188-189. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Inflammation and Repair, p. 87. [4] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 190-191.

Question 404: Anti U1-14NP antibody is seen in which condition?

A. Systemic Lupus Erythematosus (SLE)
B. Scleroderma
C. Mixed Connective Tissue Disease (MCTD) (Correct Answer)
D. Dermatomyositis

Explanation: **Explanation:** The correct answer is **Mixed Connective Tissue Disease (MCTD)**. **1. Why MCTD is correct:** Mixed Connective Tissue Disease is a distinct clinical entity characterized by overlapping features of SLE, Systemic Sclerosis (Scleroderma), and Polymyositis. The hallmark serological marker for MCTD is the presence of high titers of **Anti-U1 RNP (Ribonucleoprotein) antibodies**. The diagnosis of MCTD specifically requires the presence of these antibodies in the absence of other "extractable nuclear antigen" (ENA) antibodies like anti-dsDNA or anti-Sm. **2. Why other options are incorrect:** * **Systemic Lupus Erythematosus (SLE):** While Anti-U1 RNP can be present in SLE (approx. 30-40%), the most specific markers are **Anti-dsDNA** and **Anti-Smith (Sm)** antibodies. Anti-Sm is the pathognomonic marker for SLE. * **Scleroderma:** The characteristic antibodies are **Anti-Scl-70** (Anti-topoisomerase I) for Diffuse Cutaneous Scleroderma and **Anti-centromere** antibodies for Limited Cutaneous Scleroderma (CREST syndrome) [1]. * **Dermatomyositis:** The most specific marker is **Anti-Jo-1** (an anti-synthetase antibody), often associated with interstitial lung disease and "mechanic's hands" [2]. Other markers include Anti-Mi-2. **Clinical Pearls for NEET-PG:** * **MCTD Clinical Presentation:** Often presents with Raynaud’s phenomenon, puffy fingers/swollen hands, and myositis. * **ANA Pattern:** Anti-U1 RNP typically produces a **speckled pattern** on Immunofluorescence (IF). * **High-Yield Association:** Patients with MCTD have a lower incidence of renal and CNS involvement compared to SLE but are at high risk for **Pulmonary Hypertension**, which is a leading cause of death in these patients [1]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 238-239. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1240-1241.

Question 405: Amyloid deposits stain positively with all of the following stains except?

A. Congo Red
B. Crystal violet
C. Methenamine silver (Correct Answer)
D. Thioflavin

Explanation: **Explanation:** Amyloid is an extracellular proteinaceous material characterized by a **beta-pleated sheet** configuration [1]. This unique physical structure dictates its specific staining characteristics. **Why Methenamine Silver is the correct answer:** Methenamine silver (Grocott’s or Jones stain) is primarily used to identify **fungal organisms** and basement membranes (e.g., in renal pathology). It does not bind to amyloid fibrils. Therefore, it is the "except" option. **Analysis of incorrect options:** * **Congo Red:** The gold standard for amyloid [1]. Under ordinary light, it stains amyloid pink-red. Under polarized light, it demonstrates the pathognomonic **apple-green birefringence** due to the cross-beta-pleated sheet structure [1]. * **Crystal Violet (and Methyl Violet):** These are metachromatic stains. Amyloid takes up the blue dye but shifts the color to **rose-pink/violet**. This is a quick screening method but less specific than Congo Red. * **Thioflavin (T or S):** These are fluorescent dyes. When viewed under a fluorescence microscope, amyloid emits a **yellow-green fluorescence**. This method is highly sensitive but requires specialized equipment. **High-Yield Clinical Pearls for NEET-PG:** * **H&E Stain:** Amyloid appears as an amorphous, eosinophilic (pink), extracellular hyaline material [2]. * **Best Diagnostic Test:** Biopsy of the involved organ or **Abdominal Fat Pad Aspiration** (least invasive). * **Classification:** AL (Light chain) is associated with Multiple Myeloma; AA (Amyloid Associated) is associated with chronic inflammation (e.g., TB, Rheumatoid Arthritis) [1]. * **Scintigraphy:** Radiolabeled **Serum Amyloid P (SAP)** component can be used to localize deposits in the body. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 268-269. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Diseases Of The Urinary And Male Genital Tracts, pp. 533-534.

Question 406: 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?

A. Colorectal cancer (Correct Answer)
B. Pancreatic malignancy
C. Lymphoma
D. Gastric maltoma

Explanation: **Explanation:** The phenomenon described is **Autocrine Signaling**, where a cell secretes a messenger (growth factor or cytokine) that binds to receptors on its own surface, triggering a self-stimulatory proliferative loop. This is a hallmark of neoplastic transformation, allowing cancer cells to achieve "self-sufficiency in growth signals" [1]. **Why Colorectal Cancer is correct:** Colorectal cancer is a classic example of autocrine stimulation. Many colorectal carcinomas overexpress **Transforming Growth Factor-alpha (TGF-̑)** and its corresponding receptor, the **Epidermal Growth Factor Receptor (EGFR)** [1]. The tumor cells secrete TGF-̑, which then binds to their own EGFR, driving continuous cell cycle progression and uncontrolled growth. This pathway is the therapeutic target for monoclonal antibodies like Cetuximab. **Analysis of Incorrect Options:** * **Pancreatic malignancy:** While pancreatic cancers involve complex signaling, they are more characteristically driven by **Paracrine signaling** (interaction between tumor cells and the dense desmoplastic stroma) and constitutive activation via *KRAS* mutations rather than a pure autocrine loop. * **Lymphoma:** These are primarily driven by chromosomal translocations (e.g., *t(14;18)* in Follicular Lymphoma or *t(8;14)* in Burkitt Lymphoma) leading to the overexpression of oncogenes like *BCL2* or *MYC*, rather than autocrine loops. * **Gastric Maltoma:** This is the classic example of **Antigen-dependent proliferation**. The growth is initially driven by an external stimulus—*H. pylori* infection—which triggers a reactive B-cell response, not an internal autocrine messenger. **NEET-PG High-Yield Pearls:** * **Autocrine examples:** TGF-̑ in Glioblastoma and Colorectal cancer; IL-2 in certain T-cell leukemias [1]. * **Paracrine signaling:** Common in wound healing and the recruitment of inflammatory cells to a tumor site. * **Endocrine signaling:** Hormones traveling through the blood to distant targets (e.g., Insulin). * **Intracrine signaling:** A variation of autocrine where the messenger acts inside the cell without being secreted. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 291-293.

Question 407: Senescent cells are deficient in which enzyme?

A. RNA polymerase
B. DNA polymerase
C. Telomerase (Correct Answer)
D. Helicase

Explanation: Cellular senescence refers to the permanent arrest of the cell cycle in somatic cells after a fixed number of divisions (the **Hayflick Limit**) [2]. **1. Why Telomerase is the Correct Answer:** The primary mechanism behind replicative senescence is the progressive shortening of **telomeres** (repetitive TTAGGG sequences at the ends of chromosomes). In normal somatic cells, the enzyme **Telomerase**—a specialized reverse transcriptase—is absent or deficient [1]. Without telomerase to maintain telomere length, each cell division results in shorter telomeres [2]. Eventually, they reach a critical threshold that triggers a DNA damage response, leading to cell cycle arrest mediated by **p53 and p16/RB pathways** [1]. **2. Why Other Options are Incorrect:** * **RNA Polymerase:** This enzyme is essential for transcription (mRNA synthesis). While metabolic activity may slow down, senescent cells remain metabolically active and continue to transcribe genes; they do not lack this enzyme. * **DNA Polymerase:** This is required for DNA replication and repair. Senescent cells stop replicating DNA for division, but the enzyme itself is not the "deficient" factor causing the senescence; rather, the lack of telomere templates prevents further replication. * **Helicase:** This enzyme unwinds the DNA double helix. Deficiencies in specific helicases (e.g., *WRN* gene) cause premature aging syndromes (Werner Syndrome), but it is not the universal deficiency defining normal cellular senescence [3]. **Clinical Pearls for NEET-PG:** * **Germ cells and Stem cells:** These have high telomerase activity, allowing them to be "immortal" [1]. * **Cancer Cells:** Approximately 90% of cancer cells **reactivate telomerase**, allowing them to bypass senescence and achieve replicative immortality [1]. * **Shelterin Complex:** A protein complex that protects telomere ends; mutations here also lead to accelerated aging. * **Markers of Senescence:** Increased expression of **p16INK4a** and **Beta-galactosidase** activity. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 311-312. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 243-244. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, pp. 77-78.

Question 408: What is the chemical nature of the amyloid deposited in immunocyte dyscrasias with amyloidosis?

A. Serum amyloid A (SAA)
B. Immunoglobulin light chain (AL amyloid) (Correct Answer)
C. Prealbumin
D. Beta 2 microglobulin

Explanation: ### Explanation **Correct Answer: B. Immunoglobulin light chain (AL amyloid)** **Underlying Concept:** Immunocyte dyscrasias, such as **Multiple Myeloma** or B-cell lymphomas, are characterized by the monoclonal proliferation of plasma cells [1]. These neoplastic cells secrete excessive amounts of abnormal immunoglobulins or, more commonly, free **immunoglobulin light chains** (typically the Lambda type). These light chains undergo limited proteolysis to form **AL (Amyloid Light chain)** protein, which deposits in tissues as insoluble fibrils [1]. This is the most common form of systemic amyloidosis (Primary Amyloidosis). **Analysis of Incorrect Options:** * **A. Serum amyloid A (SAA):** This is an acute-phase reactant produced by the liver. Its derivative, **AA amyloid**, is deposited in **Secondary Amyloidosis**, which occurs due to chronic inflammatory conditions like Rheumatoid Arthritis, Tuberculosis, or Osteomyelitis. * **C. Prealbumin:** Now known as **Transthyretin (TTR)**. Mutant TTR is found in Familial Amyloid Polyneuropathies, while wild-type TTR deposits in the hearts of elderly patients (Senile Systemic Amyloidosis). * **D. Beta 2 microglobulin:** This is a component of MHC Class I molecules. It deposits as amyloid in patients on **long-term hemodialysis** because the molecule is not efficiently filtered by dialysis membranes. **High-Yield Clinical Pearls for NEET-PG:** * **Staining:** All amyloid types show **Apple-green birefringence** under polarized light when stained with **Congo Red** [1]. * **Light Chain Type:** In AL amyloidosis, **Lambda ($\lambda$)** light chains are more frequently amyloidogenic than Kappa ($\kappa$) chains (Ratio 2:1), despite Kappa being more common in normal serum. * **Bence-Jones Proteins:** These are free light chains found in the urine of patients with Multiple Myeloma; they are the precursors to AL amyloid. * **Diagnosis:** Abdominal fat pad aspiration or rectal biopsy are the preferred initial screening sites for systemic amyloidosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 266-267.

Question 409: Klinefelter syndrome is diagnosed by:

A. USG abdomen
B. Echocardiography
C. Triple test
D. Karyotyping (Correct Answer)

Explanation: **Explanation:** **Klinefelter Syndrome** is a chromosomal disorder characterized by the presence of at least one extra X chromosome in a male, most commonly resulting in a **47,XXY** genotype [3]. Since the underlying pathology is a numerical chromosomal aberration (aneuploidy) caused by meiotic non-disjunction, **Karyotyping** is the gold standard and definitive diagnostic method [1]. It allows for the visualization of the extra X chromosome and identifies mosaic forms (e.g., 46,XY/47,XXY) [2]. **Analysis of Incorrect Options:** * **USG Abdomen:** While it may be used to evaluate small testes or cryptorchidism, it cannot provide a definitive genetic diagnosis. * **Echocardiography:** This is used to detect structural heart defects (like Mitral Valve Prolapse, which can occur in Klinefelter), but it is not a diagnostic tool for the syndrome itself. * **Triple Test:** This is a prenatal screening tool (measuring AFP, hCG, and estriol) used primarily to screen for Down syndrome and neural tube defects, not for diagnosing Klinefelter syndrome. **Clinical Pearls for NEET-PG:** * **Classic Phenotype:** Tall stature, long extremities (eunuchoid habitus), gynecomastia, and small, firm testes. * **Laboratory Findings:** Hypergonadotropic hypogonadism (↑ FSH, ↑ LH, ↓ Testosterone) due to testicular dysgenesis. * **Histology:** Characterized by **hyalinization and fibrosis of seminiferous tubules** and apparent Leydig cell hyperplasia. * **Infertility:** It is the most common genetic cause of male infertility and azoospermia. * **Barr Body:** Positive (due to the extra X chromosome). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 167-168. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 54-55. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 92-93.

Question 410: Which of the following features is not characteristic of Fragile X syndrome?

A. Hyperextensible joints
B. Small nose
C. Mental retardation
D. Micro-orchidism (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Micro-orchidism**. This is because Fragile X syndrome is classically characterized by **Macro-orchidism** (enlarged testes), typically appearing post-puberty, rather than micro-orchidism [1]. ### Why Option D is the Correct Answer: Fragile X syndrome is the most common cause of inherited intellectual disability. It is caused by a **CGG trinucleotide repeat expansion** in the *FMR1* gene on the X chromosome, leading to gene silencing [1]. The hallmark physical finding in post-pubertal males is **Macro-orchidism** (testicular volume >25 ml) [1]. Therefore, "Micro-orchidism" is the incorrect feature and the right choice for this "except" type question. ### Analysis of Incorrect Options: * **A. Hyperextensible joints:** Patients often exhibit connective tissue dysplasia, leading to joint hypermobility, flat feet, and mitral valve prolapse. * **B. Small nose:** While the classic facial profile includes a long face and large everted ears, a **prominent forehead** and a relatively **small/short nose** (or a broad nasal bridge) are recognized dysmorphic features. * **C. Mental retardation:** Fragile X is the leading inherited cause of intellectual disability (mental retardation), second only to Down Syndrome (which is chromosomal/sporadic) [1]. ### NEET-PG High-Yield Pearls: * **Genetics:** X-linked dominant inheritance with variable expressivity; shows **Genetic Anticipation** (severity increases in successive generations) [1]. * **Molecular Basis:** CGG repeats >200 lead to **hypermethylation** of the *FMR1* gene [1]. * **Clinical Triad:** Intellectual disability, large everted ears, and macro-orchidism. * **Behavioral:** Strong association with **Autism Spectrum Disorder** and ADHD. * **Diagnosis:** PCR and Southern Blot (to count repeats and assess methylation). **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 177-181.

Practice by Chapter

Cell Injury and Cell Death

Practice Questions

Adaptations of Cellular Growth

Practice Questions

Accumulations and Deposits

Practice Questions

Acute and Chronic Inflammation

Practice Questions

Tissue Repair and Wound Healing

Practice Questions

Hemodynamic Disorders

Practice Questions

Genetic Disorders

Practice Questions

Environmental Pathology

Practice Questions

Nutritional Diseases

Practice Questions

Molecular Basis of Disease

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free