This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolic Disorders Leading to Osteosclerosis, Subject name: Orthopaedics
[{'content': 'A 3 year male presented with progressive anemia, hepatosplenomegaly and osteomyelitis of jaw with pathological fracture, x-ray shows chalky white deposits on bone, probable diagnosis is \nSelect and explain. \nA. osteopetrosis, B. osteopoikilocytosis, C. alkaptonuria, D. myositis- ossificans progressiva', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e osteopetrosis Osteopetrosis (also known as Marble bone disease, Albers- Schonberg disease)Defect is in bone resorption due to abnormal function of osteoclasts.Defective bone resorption results in uniformly thickened dense bones, often without distinction between cortical and cancellous regions. The bones are dense but brittle therefore known as marble bone disease.Inheritance is both AD & AR*.The AR form dies early in the life.The AD form is of milder variety.Clinical features in osteopetrosis are caused byan increased tendency to fractures and osteomyelitis.Encroachment of the marrow space leading to anaemia and extramedullary hematopiesis- hepato splenomegaly & cranial nerve compression.", 'role': 'assistant'}]