Ans: D. GlucocerebrosideGaucher's disease:* MC lysosomal storage disorder, autosomal recessive in inheritance.* Caused by deficiency of tissue enzyme glucocerebrocidase.Glucocerebrocidase:* Splits glucose from glucosyl ceramide. Hence, accumulates glucocerebroside.* Glucosyl ceramide - Cerebrocide accumulates in cell of reticuloendothelial system.Clinical history:* Hepatosplenomegaly with crumpled tissue paper appearance on biopsy - Highly suggestive of Gaucher's disease.* Pancytopenia & thrombocytopenia secondary to hypersplenism.* Widened marrow cavity - Due to Gaucher's cells deposition. - Expansion of bone is prominent - Especially at lower end of femur & humerus. - Causes pathologic fracture & bone pain.Treatment:* Enzyme replacement therapy done with natural or recombinant glucocerebrocidase.(Ref Harrison 19/e p432-e5; Robbins 9/e p151-154, 8/e p153; Nelson 20/e p708, 19/e p487, 488, 500)