Biology, Genetics & Bone Healing MCQs

A 3-year-old severely malnourished child presents with refusal to walk, bleeding gums, and corkscrew hairs. Radiographs of the knee show a dense zone of provisional calcification (white line of Frankel) and a ringed epiphysis (Wimberger ring sign). The primary biochemical defect in this disorder impairs which process?

A 12-year-old child presents with recurrent fractures, anemia, hepatosplenomegaly, and cranial nerve palsies. Radiographs show diffuse osteosclerosis and 'Erlenmeyer flask' deformities of the distal femora. What is the fundamental pathophysiology underlying this disease?

A 7-year-old boy presents with a waddling gait and delayed eruption of secondary teeth. Radiographs reveal bilateral absence of the clavicles and widened cranial sutures. A mutation in which of the following transcription factors is most likely responsible?

A 65-year-old man presents with progressive bowing of his right tibia and hearing loss. Radiographs show cortical thickening, coarse trabeculae, and anterior bowing. Bone biopsy reveals a mosaic pattern of lamellar bone. A mutation in which gene is commonly associated with the familial form of this disease?

A 14-year-old boy presents with progressive knee valgus. Labs show normal serum calcium, decreased serum phosphate, normal PTH, normal 25-OH vitamin D, and elevated alkaline phosphatase. Which of the following is the most likely diagnosis?

A 45-year-old patient with end-stage renal disease on hemodialysis presents with bone pain. Radiographs demonstrate subperiosteal resorption of the radial aspects of the middle phalanges and a "rugger jersey" spine. What is the primary pathophysiologic driver of this patient's bone disease?

An 8-year-old child presents with multiple fractures and disproportionate short stature. Radiographs show a "bone within a bone" appearance in the spine and Erlenmeyer flask deformities of the distal femora. Labs reveal severe anemia and thrombocytopenia. What is the most likely defective mechanism?

A 55-year-old woman is evaluated for atraumatic osteolysis of the distal clavicle and diffuse joint pains. Laboratory results show markedly elevated serum calcium, low phosphorus, and elevated parathyroid hormone (PTH) levels. Dual-energy X-ray absorptiometry (DEXA) reveals severe cortical bone loss. What is the primary skeletal manifestation of this disease?

A 5-year-old boy presents with progressive limb bowing, waddling gait, and premature loss of primary teeth. Laboratory testing shows hypercalcemia, normal parathyroid hormone, and markedly low serum alkaline phosphatase. Elevated levels of urine phosphoethanolamine are noted. What is the most likely diagnosis?

A 65-year-old man presents with progressive bowing of his right tibia and dull, aching bone pain. Labs show isolated markedly elevated alkaline phosphatase with normal calcium and phosphorus. Radiographs reveal cortical thickening and coarsened trabeculae. What is the primary cellular pathophysiology initiating this disease process?

A 12-year-old boy is evaluated for retained deciduous teeth and an unusual ability to bring his shoulders together anteriorly. Radiographs demonstrate a widened symphysis pubis and hypoplastic clavicles. The mutated gene responsible for this condition primarily affects which of the following cellular processes?

A 4-year-old boy presents with a femur fracture after a minor fall. His medical history is significant for severe anemia, hepatosplenomegaly, and bilateral hearing loss. Radiographs reveal diffusely sclerotic bones with absent medullary canals and an "Erlenmeyer flask" deformity of the distal femora. What is the fundamental cellular defect in this condition?

A 5-year-old boy presents with short trunk dwarfism, a barrel chest, a waddling gait, and high myopia. Radiographs show delayed ossification of the femoral heads and flattening of the vertebral bodies. A mutation in which collagen type is associated with this condition?

A 12-year-old girl is noted to have excessive mobility of her shoulders, allowing her to touch them together anteriorly. Radiographs show hypoplastic clavicles and delayed closure of the cranial sutures. What transcription factor is mutated in this disorder?

A 45-year-old female presents with progressive osteolysis of her left hemipelvis and proximal femur, diagnosed as Gorham-Stout disease.

Alongside surgical stabilization, which pharmacological agent has shown the most efficacy in slowing the osteolytic process?

A 12-year-old boy presents with delayed tooth eruption, hypermobility of the shoulders allowing them to meet in the midline, and a wide, flat skull. Which transcription factor is mutated in this condition?

A 32-year-old male with confirmed Gorham-Stout disease of the left femur is experiencing progressive, massive osteolysis despite conservative care.

Which of the following medical treatments has shown efficacy in slowing the osteolytic process in this disease?

A 4-year-old child presents with short stature, bowlegs, and a waddling gait. Radiographs reveal flared, irregular metaphyses but normal epiphyses and spine. Laboratory studies show normal calcium, phosphorus, and alkaline phosphatase. Which collagen gene is typically mutated?

A 5-year-old male presents with short trunk dwarfism, a barrel chest, and coxa vara. He has normal intelligence and normal-sized hands and feet. Radiographs show flattened vertebral bodies and delayed ossification of the epiphyses. Which structure's underlying defect is responsible for this condition?

What is the primary histological feature driving the massive osteolysis seen in Gorham-Stout disease?