General Pathology Practice Questions

Q: Mitochondrial chromosomal abnormality leads to which of the following conditions?

Lebers hereditary optic neuropathy. **Explanation:** **Leber’s Hereditary Optic Neuropathy (LHON)** is the correct answer because it is a classic example of a disorder caused by **mitochondrial DNA (mtDNA) mutations** [1]. Since mitochondria are inherited exclusively from the oocyte, LHON follows a **maternal inheritance pattern** (all children of an affected mother are at risk, but affected fathers do not pass it to their offspring). Pathophysiologically, mutations in mtDNA genes (encoding subunits of NADH dehydrogenase) lead to defective oxidative phosphorylation, causing selective degeneration of retinal ganglion cells and subsequent bilateral central vision loss. **Analysis of Incorrect Options:** * **Angelman Syndrome & Prader-Willi Syndrome:** These are examples of **Genomic Imprinting** (epigenetic regulation) involving chromosome 15 [1]. Angelman results from the loss of the maternal allele (UBE3A gene), while Prader-Willi results from the loss of the paternal allele. * **Myotonic Dystrophy:** This is a **Trinucleotide Repeat Disorder** (CTG repeat in the DMPK gene) [1]. It follows an Autosomal Dominant pattern and exhibits "anticipation." **High-Yield Clinical Pearls for NEET-PG:** * **Mitochondrial DNA (mtDNA):** It is circular, double-stranded, and lacks histones. It has a higher mutation rate than nuclear DNA. * **Heteroplasmy:** This term refers to the coexistence of wild-type and mutated mtDNA within a single cell [1]. The severity of mitochondrial diseases depends on the proportion of mutated mtDNA (Threshold effect) [1]. * **Other Mitochondrial Diseases:** MELAS (Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes) and MERRF (Myoclonic Epilepsy with Ragged Red Fibers). * **Histology:** "Ragged Red Fibers" on Gomori trichrome stain are a hallmark of mitochondrial myopathies. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 177, 181.

Question 1

Which of the following is true about proto-oncogenes?

Accepted Answer

Important for normal cell growth

Answer

Involved in oncogenesis

Answer

C-myc overexpression causes lymphoma

Answer

Mutation causes Retinoblastoma

Question 2

Mitochondrial chromosomal abnormality leads to which of the following conditions?

Accepted Answer

Lebers hereditary optic neuropathy

Answer

Angelman syndrome

Answer

Prader Willi syndrome

Answer

Myotonic dystrophy

Question 3

Congo red staining of abdominal fat has confirmed a diagnosis of Amyloidosis in a 28-year-old man. Which is the most common cause of death in primary AL Amyloidosis?

Accepted Answer

Cardiac failure

Answer

Respiratory failure

Answer

Renal failure

Answer

Septicemia

Question 4

Karyotyping is useful in the diagnosis of which type of condition?

Accepted Answer

Chromosomal abnormalities

Answer

Autosomal recessive disorders

Answer

X-linked recessive disorders

Answer

Biochemical abnormalities

Question 5

A 56-year-old male patient complains of swelling in his legs. He is a known case of hypertension and is under treatment. On general physical examination, pitting edema is seen on the legs, and his TSH level is 3 mU/L. Which of the following is not a cause of this condition?

Accepted Answer

Myxedema

Answer

Increase in hydrostatic pressure

Answer

Decreased colloid osmotic pressure

Answer

Lymphatic obstruction

Question 6

Supratemporal lenticular subluxation is seen in which condition?

Accepted Answer

Marfan syndrome

Answer

Weil's disease

Answer

Hunter syndrome

Answer

Homocystinuria

Question 7

What is true about autosomal dominant inheritance?

Accepted Answer

50% affected, if one parent is affected.

Answer

25% affected and 50% carrier, if one parent is affected.

Answer

50% affected and 75% carrier, if both parents are affected.

Answer

75% affected, if both parents are affected.

Question 8

Which of the following is NOT a form of reversible cellular injury?

Accepted Answer

Karyorrhexis

Answer

Vacuolar degeneration

Answer

Fat accumulation

Answer

Cell swelling

Question 9

Hemosiderin contains which of the following elements?

Accepted Answer

Iron

Answer

Calcium

Answer

Magnesium

Answer

None of the above

Question 10

Annexin V is associated with which of the following processes?

Accepted Answer

Apoptosis

Answer

Necrosis

Answer

Atherosclerosis

Answer

Inflammation

General Pathology — MCQs

General Pathology — MCQs

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