1. General Principles & Basic Science MCQs

Review the radiograph of an infant presenting with multiple fractures, hepatosplenomegaly, and pancytopenia.

Which of the following is the most definitive, potentially curative treatment for the malignant infantile form of this disease?

A 65-year-old male with active Paget's disease is scheduled for an elective total hip arthroplasty due to severe secondary osteoarthritis. His alkaline phosphatase is currently 4 times the upper limit of normal. What is the most appropriate preoperative medical optimization?

The radiograph below demonstrates classical findings of a metabolic bone disorder.

The pathogenesis of this condition initially involves overactivity of which cell type, commonly linked to which gene mutation in familial cases?

A child presents with sparse hair, a bulbous nose, cone-shaped epiphyses, and multiple osteochondromas. A contiguous gene deletion syndrome is diagnosed. Loss of which two genes is responsible for this exact phenotype?

A patient with autosomal recessive osteopetrosis is found to have a specific mutation in the carbonic anhydrase II (CAII) gene. Which of the following systemic manifestations is uniquely associated with this specific mutation variant?

A 68-year-old woman presents with progressive hearing loss and an increasing hat size. A skull radiograph is shown.

What is the expected laboratory profile for this patient?

Histological examination of a bone biopsy from a patient with severe, untreated osteopetrosis would most classically reveal which of the following characteristic features?

A 65-year-old male presents with bone pain and enlarging skull size. Lab tests reveal isolated elevation of alkaline phosphatase. The primary cellular defect in this condition involves a mutation affecting which of the following?

A child with recurrent fractures, pancytopenia, and hepatosplenomegaly is diagnosed with malignant infantile osteopetrosis. The pathogenesis of this disease is best described by the failure of which process?

A 58-year-old man requires a total hip arthroplasty for severe secondary osteoarthritis due to Paget's disease. Why is preoperative administration of intravenous bisphosphonates recommended for this patient?

A 24-year-old male presents with a history of recurrent fractures since childhood. Radiographs reveal a 'bone-within-a-bone' appearance and uniformly dense vertebral bodies with a 'rugger jersey' spine pattern. What is the fundamental cellular defect responsible for this condition?

A 65-year-old female presents with chronic deep aching pain in her right thigh and progressive bowing of her lower leg. Laboratory studies show a significantly elevated alkaline phosphatase but normal calcium and phosphorus. Which of the following is the first-line medical management for her underlying bone disease?

An infant presents with macrocephaly, severe anemia, thrombocytopenia, and hepatosplenomegaly. Radiographs reveal diffuse, uniformly dense bones with loss of the medullary canal. What is the only potential curative treatment for this severe infantile disorder?

Which of the following laboratory profiles is most characteristic of active, uncomplicated Paget's disease of bone?

Trichorhinophalangeal syndrome type 1 (TRPS1) is inherited in an autosomal dominant pattern. The mutated gene in this syndrome predominantly affects which of the following cellular processes?

A 68-year-old male presents with increasing hat size over the past year. A lateral skull radiograph reveals a large, well-defined osteolytic lesion involving the frontal and occipital bones.

What phase of his underlying disease does this 'osteoporosis circumscripta' represent?

A 72-year-old male with severe, polyostotic Paget's disease presents with progressive dyspnea, fatigue, and lower extremity edema. Assuming his cardiac symptoms are a direct complication of his bone disease, echocardiography is most likely to demonstrate which of the following?

A 68-year-old man presents with progressive enlargement of his skull and increasing deafness. Radiographs reveal a 'cotton-wool' appearance of the calvarium. A mutation in which of the following genes is most commonly implicated in the pathogenesis of this patient's condition?