Acquired cutis laxa from heavy chain deposition disease

(eng) A 35-year-old woman presented with fatigue, nausea, marked lower-limb edema, and hypertension (180/100 mm Hg). Blood tests showed kidney failure (serum creatinine: 10 mg/dl), and urinalysis demonstrated heavy proteinuria (10 g/d) with microscopic hematuria. Her serum C3 level was low (0.75 g/l; N > 0.9). Serum immunoblot analysis identified a truncated monoclonal γ4 heavy chain with deletion of the CH1 domain. The patient looked much older than her age, with inelastic and sagging skin on her face, neck, axillae, and groin areas. Kidney biopsy showed nodular glomerulosclerosis with linear deposits of gamma heavy chain and C3 along tubular and glomerular basement membranes, without staining for kappa or lambda light chains. Electron microscopy revealed finely granular electron-dense deposits in the mesangium and along the inner aspect of the glomerular basement membrane. A skin biopsy revealed linear deposition of gamma 4 heavy chain, C1Q, and C4D along dermic elastic fibers.