Explanation:
Gaucher disease is the most common lysosomal storage disorder. It is an autosomal recessive condition caused by a deficiency of the enzyme glucocerebrosidase. This leads to the accumulation of glucocerebroside within the lysosomes of macrophages (forming 'Gaucher cells'). The infiltration of these cells into the bone marrow causes bone pain, marrow expansion (leading to the classic Erlenmeyer flask deformity of the distal femur), ischemia, and frequent avascular necrosis of the femoral heads. Reference: Miller's Review of Orthopaedics, 8th Edition.