An infant presents with painful swollen joints, subcutaneous nodules over the hands and wrists, hoarse crying, and progressive joint contractures. Biopsy of a nodule shows granulomatous inflammation with storage of lipid in macrophages. Deficiency of which enzyme explains this presentation?

• A Acid ceramidase ✓
• B Hexosaminidase B
• C Alpha-galactosidase A
• D Beta-galactocerebrosidase

Explanation

Farber lipogranulomatosis results from acid ceramidase deficiency, causing accumulation of ceramide in lysosomes of macrophages and other tissues. The hallmark triad is painful periarticular swelling with subcutaneous lipogranulomas, a hoarse voice from laryngeal involvement, and progressive joint deformity. Hexosaminidase B deficiency causes Sandhoff disease with neurodegeneration rather than painful nodules, alpha-galactosidase A deficiency causes Fabry disease, and beta-galactocerebrosidase deficiency causes Krabbe leukodystrophy.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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